Diss. (sammanfattning) Linköping : Univ., 2001. / Härtill 4 uppsatser.

Thesis (Ph.D.)(Biochemistry))--University of Pretoria, 2008. / Includes bibliographical references.

Thesis (PhD)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The evaluation of the immune responses in peripheral blood and at the site of disease of people with differential outcomes following M.tb exposure will lead to the discovery of host biomarkers that will increase our understanding of the protective and non-protective immune responses against the bacterium. The main study consisted of a number of pilot studies and the objectives of the studies were: (1) To determine the background and stimulated whole blood cytokine profiles of children and adults of the community; (2) to establish biomarker profiles in whole blood of children with different M.tb infection phenotypes; (3) to investigate the anti-mycobacterial whole blood immune responses in HIV infected and uninfected children; (4) and to investigate the role of the innate immune system during human tuberculosis disease. The study designs were as follow: (1) Adults and children were enrolled in order to determine cytokine profiles in the community. Whole blood was stimulated with BCG and ESAT-6 or left unstimulated. Eighteen cytokines were measured in supernatants of each condition. Progression to active tuberculosis in the years after study participation was assessed by searching for patient entries in the tuberculosis register. (2) Children with known tuberculosis exposure in their households and with M.tb infection as assessed through interferon-ã release assays, children with exposure but no infection and a control group with no exposure and no infection were investigated. Whole blood was stimulated in QuantiFeron tubes overnight and 21 cytokines were measured in antigen stimulated and unstimulated supernatants by multiplex cytokine arrays. (3) HIV infected and uninfected children were enrolled in a hospital based study. Whole blood interferon-ã responses against specific mycobacterial antigens were investigated in a diluted 7 day whole blood assay and compared to QuantiFeron supernatants from the same participants. (4) Tuberculosis diseased adults were enrolled before the onset of treatment and innate and adaptive cell populations were investigated upon start of treatment and at treatment end. In addition, pleural effusion fluid was collected from tuberculosis and cancer patients and innate cell populations further investigated. The studies were performed in Cape Town, South Africa and included Tygerberg Academic Hospital and the surrounding neighbourhoods of Ravensmead, Uitsig and Elsies River. The main findings of the studies included: (1) We showed age related cytokine differences in our study community. Tuberculosis progressors had significantly higher levels of IL-10 in the unstimulated sample several years before the onset of tuberculosis disease. (2) Cytokines that distinguished best between children with tuberculosis infection and no infections were all cytokines that correlated with interferon-ã (interferon-ã was used to make the classification of M.tb infected and uninfected). Higher IL-1â and lower IL-17 levels in children with tuberculosis exposure without subsequent M.tb infection compared to children with no exposure were shown. (3) HIV infected children showed better responses after 7 day whole blood antigen stimulation compared to the overnight stimulation in QuantiFeron tubes. TB10.4 stimulation in HIV infected TST positive children gave higher interferon-ã responses than ESAT-6 and CFP-10. (4) The presence of myeloid derived suppressor cells is shown during tuberculosis disease circulating in peripheral blood. Upon treatment a decrease in the population is observed. No differences were seen in the myeloid derived suppressor cell frequencies between tuberculosis and cancer patients, however significantly lower frequencies were seen in healthy controls. The immune response against M.tb is complex and interactions between the different cell types are essential to control and fight infection and disease. In this thesis we presented new biomarkers that play important roles during different stages of M.tb pathogenesis from exposure to infection and even during disease. These may shed light on mechanisms of protection against M.tb, relevant to development of tuberculosis diagnostics and vaccine strategies. Combinations of multiple biomarkers including cytokines and chemokines and cell subsets are required to characterize biosignatures relevant to the diagnosis of tuberculosis infection and disease. / AFRIKAANSE OPSOMMING: Deur die immuunreaksie te ondersoek, in heelbloed en in die setel van infeksie, in mense met verskillende uitkomste van M.tb blootstelling sal lei tot die ontdekking van biologiese merkers en sal bydra tot ons begrip van die beskermde en nie-beskermde immuunreaksies teen die bakterium. Die hoofstudie het bestaan uit ‘n aantal loodsstudies en die doel van die studies was: (1) Om die sitokienprofiele in gestimuleerde heelbloed, asook agtergrond waardes, van kinders en volwassenes te bepaal, in die gemeenskap; (2) om die profiele van biologiese merkers in heelbloed van kinders met verskillende M.tb infeksie fenotipes te bepaal; (3) om die anti-mykobakteriële immuunreaksies in heelbloed by MIV geïnfekteerde en nie-geïnfekteerde kinders te bepaal; (4) om ondersoek in te stel na die doel van die aangebore immuunsisteem tydens tuberkulose siekte. Die studie ontwerpe was soos volg: (1) Volwassenes en kinders het deelgeneem aan die ondersoek van sitokienprofiele in die gemeenskap. Heelbloed is gestimuleer met BCG en ESAT-6 of is ongestimuleerd gelaat. Agtien sitokiene is gemeet in die bo-stand verkry van elke kondisie. Mense wat aktiewe tuberkulose siekte in die jare na die studie ontwikkel het, is geïdentifiseer deur die pastiëntinligting in die tuberkulose-register. (2) Kinders met gedokumenteerde huishoudelike tuberkulose blootstelling en met M.tb infeksie, soos bepaal deur vrygelate interferon-ã toetse, kinders met blootstelling maar geen infeksie en ‘n kontrole groep met geen blootstelling en geen infeksie, is ondersoek. Heelbloed is gestimuleer in die QuantiFeron buise oornag en 21 sitokiene is gemeet in die antigeen gestimuleerde en ongestimuleerde bostande deur die multiplex sitokienpaneel. (3) MIV geïnfekteerde en nie-geïnfekteerde kinders het deelgeneem aan ‘n hospitaal baseerde studie. Heelbloed interferon-ã reaksies teen spesifieke mykobakteriële antigene is bestudeer in ‘n verdunde 7 dag heelbloed toets en vergelyk met die QuantiFeron bostande van dieselfde deelnemers. (4) Siek tuberkulose volwassenes wat nie op behandeling is nie, het deelgeneem. Die aangebore en verworwe selpopulasies is bepaal aan die begin van behandeling asook voor die einde van behandeling. Verder is pluralevog van tuberkulose en kanker pastiënte bestudeer vir aangebore selpopulasies. Die studies is uitgevoer in Kaapstad, Suid-Afrika en sluit in Tygerberg Akademiese Hospitaal en die gemeenskappe van Ravensmead, Uitsig en Elsiesrivier. Die hoofbevindinge van die studies sluit in: (1) Ons het gewys dat daar ouderdomsverwante sitokien verskille in die studie gemeenskap is. Mense wat tuberkulose siekte ontwikkel het, het beduidende hoër vlakke van IL-10 in die ongestimuleerde monsters getoon ‘n paar jaar voor die begin van die siekte. (2) Sitokiene wat die beste onderskeiding gewys het tussen infeksie en geen infeksie was sitokiene wat ook korrelasie getoon het met interferon-ã (interferon-ã is gebruik om die klassifikasie te maak van M.tb infeksie of geen infeksie). Hoër IL-1â en laer IL-17 vlakke in kinders met tuberkulose blootstelling en sonder M.tb infeksie, is gewys wanneer dit vergelyk is met kinders sonder blootsteling. (3) MIV geïfekteerde kinders het beter reaksies getoon na 7 dag heelbloed antigeen stimulasie as met die oornag stimulasie in QuantiFeron buise. TB10.4 stimulasie in MIV geïnfekteerde TST positiewe kinders het hoër interferon-ã reaksies getoon as na stimulasie met ESAT-6 en CFP-10. (4) Die teenwoordigheid van miloïed afgeleide onderdrukkende selle in heelbloed, is getoon tydens tuberkulose siekte. Na behandeling is ‘n afname in die populasie gesien. Geen verskille is gesien in die aantal miloïed afgeleide onderdrukkende selle tussen tuberkulose en kanker pastiënte nie, alhoewel beduidende laer getalle is waargeneem in gesonde kontrole deelnemers. Die immuunreaksie teen M.tb is kompleks en interaksies tussen die verskillende seltipes is belangrik om infeksie en siekte te kontroleer en te beveg. In die tesis het ons nuwe biologiese merkers geïdentifiseer wat belangrike funksies het, tydens die verskillende stadiums van M.tb patogenesiteit, van blootstelling tot infeksie asook tydens siekte. Dit kan gebruik word as biologiese merkers betrokke by die immuunreaksie teen M.tb en sal bydra tot die diagnose van tuberkulose infeksie en siekte.

No description available.

A tuberculose é uma doença crônica granulomatosa caracterizada por um déficit de imunidade antígeno específica do hospedeiro, cuja resposta imune é ativamente regulada por citocinas. No Brasil há mais de 50 milhões de habitantes infectados pelo Mycobacterium tuberculosis. O objetivo foi avaliar a linfoproliferação e a produção de citocinas por células mononucleares do sangue periférico (PBMC) estimuladas por quatro diferentes antígenos do M. tuberculosis, um complexo, o antígeno sonicado, e três purificados, ESAT-6, antígeno 85B e antígeno HBHA, eventuais candidatos à vacina anti-tuberculose. Para avaliação da produção de IFN-g e IL-10 foram utilizados dois métodos: Elispot e Elisa à partir de sobrenadante de cultura de PBMC. Para essas avaliações, os pacientes com tuberculose ativa (TB-A) foram comparados a dois subgrupos de indivíduos controles. O primeiro subgrupo foi constituído por indivíduos saudáveis PPD+ e o segundo por indivíduos curados de um episódio de tuberculose (TB-C). Nossos resultados de linfoproliferação e de Elisa revelaram diminuição da resposta linfoproliferativa e da produção de IFN-g dos pacientes em comparação com os indivíduos PPD+, enquanto os indivíduos TB-C apresentaram em geral resultados intermediários. Observou-se também que as respostas à PHA não diferiam significativamente entre os grupos, ressaltando a natureza antígeno específica da hiporreatividade na tuberculose. Adicionalmente, verificamos maior reatividade ao antígeno complexo, sonicado, que aos antígenos purificados, e entre estes, a reatividade foi maior para ESAT-6 e 85B que para HBHA, A resposta ao HBHA pode ter sido eventualmente subestimada por razões técnicas, como utilização de dose sub-ótima ou perda da atividade biológica. Em relação ao Elispot para IFN-g, não pudemos observar diferenças entre os grupos, tanto quando se considerou o número total de spots, como quando se contou apenas spots com diâmetro > 65 mm, apresentando portanto uma sensibilidade aparentemente menor comparado aos outros 2 métodos. A comparação entre os métodos revelou pouca correlação entre seus resultados, que pode ser eventualmente explicado pela diferente contribuição das populações celulares (T CD4+ e T CD8+) para cada uma das provas munológicas. Finalmente, a análise da produção de IL-10 medida por Elisa no sobrenadante de cultura e por spots de IL10, também não revelou diferenças entre os grupos. Convém notar que o Elisa detectou baixas concentrações de IL-10 nos sobrenadantes, porém o Elispot demonstrou número elevado de spots e boa correlação entre as resposta aos antígenos. Em conclusão, nossos resultados sugerem que métodos \'clássicos\', e já estabelecidos, como linfoproliferação e Elisa, persistem válidos para se avaliar a imunidade celular, e que em nossas condições laboratoriais, a técnica de Elispot não representou, até o momento, uma melhora na qualidade da avaliação imunológica. / Tuberculosis is a chronic granulomatous disease characterized by a deficit of the antigen-specific immunity of the host, whose immune response is actively regulated by cytokines. In Brazil there are 50 million people infected with Mycobacterium tuberculosis. The objective of the present work was to evaluate the lymphoproliferative response e the IFN-g response by peripheral blood mononuclear cells (PBMC) indiced with 4 different antigens isolated from Mycobacterium tuberculosis: a complex, crude, the sonicate antigen, and 3 other, purified ones, Esat-6, 85B, and HBHA, the last 3 eventual candidates to the design of a vaccine against tuberculosis. We used 2 methods to evaluate the IFN-g and IL-10 productions, namely Elispot and Elisa of supernatant of PBMC cultures. We studied a group of active tuberculosis patients (TB-A), and compared them with controls individuals comprising 2 groups, one made of healthy PPD+ individuals and the second one of individuals who have been cured from an episode of tuberculosis in the past (TB-C). Our results of lymphoproliferation and Elisa revealed decrease in the lymphoproliferative and IFN-g responses by patients\' PBMC as compared to the PPD+ group, with the TB-C group in general presenting intermediate results. We also observed that the responses to the mitogen PHA were not statisically different among the groups, denoting the antigen-specific nature of the immune deficit in tuberculosis. In addition, we verified that stronger reactivity to the complex antigen than with the purified antigens, and, among the latter, the reactivity was stronger with Esat-6 and 85B as compared to HBHA, Reactivity to HBHA may have been understimated due to technical reasons, such as loss of .the biological activity of the molecule or use of a sub-optimal dose. By using the Elispot for IFN-g we were not able to detect differences among the groups, even when we counted all spots formed or spots with more than > 65 mm in diameter. Thus our Elispot for IFN-g apparently showed lower sensitivity than the other 2 methods. Furthermore, comparisons between the methods revealed low correlation between their results, a finding that may be explained by the differning contribution of different subpopulations (T CD4+ and T CD8+) to each of the results. Finally, analysis of the production of IL-10 as measured by Elisa in the culture supernatants as well as by Elispot revealed no differences among the groups. It is noteworthy that the levels of IL-10 detected by Elisa were low, but the Elispot revealed high number of spots and a good correlation between the antigen responses. In conclusion, we may say that our well standardized \'classical\' methods Elisa and lymphoproliferation persist useful to evaluate cellular immunity responses, and that the Elispot technique, up to now and in our laboratorial conditions, did not represent an improvement in the quality of the immunological evaluation.

A tuberculose é uma doença crônica granulomatosa caracterizada por um déficit de imunidade antígeno específica do hospedeiro, cuja resposta imune é ativamente regulada por citocinas. No Brasil há mais de 50 milhões de habitantes infectados pelo Mycobacterium tuberculosis. O objetivo foi avaliar a linfoproliferação e a produção de citocinas por células mononucleares do sangue periférico (PBMC) estimuladas por quatro diferentes antígenos do M. tuberculosis, um complexo, o antígeno sonicado, e três purificados, ESAT-6, antígeno 85B e antígeno HBHA, eventuais candidatos à vacina anti-tuberculose. Para avaliação da produção de IFN-g e IL-10 foram utilizados dois métodos: Elispot e Elisa à partir de sobrenadante de cultura de PBMC. Para essas avaliações, os pacientes com tuberculose ativa (TB-A) foram comparados a dois subgrupos de indivíduos controles. O primeiro subgrupo foi constituído por indivíduos saudáveis PPD+ e o segundo por indivíduos curados de um episódio de tuberculose (TB-C). Nossos resultados de linfoproliferação e de Elisa revelaram diminuição da resposta linfoproliferativa e da produção de IFN-g dos pacientes em comparação com os indivíduos PPD+, enquanto os indivíduos TB-C apresentaram em geral resultados intermediários. Observou-se também que as respostas à PHA não diferiam significativamente entre os grupos, ressaltando a natureza antígeno específica da hiporreatividade na tuberculose. Adicionalmente, verificamos maior reatividade ao antígeno complexo, sonicado, que aos antígenos purificados, e entre estes, a reatividade foi maior para ESAT-6 e 85B que para HBHA, A resposta ao HBHA pode ter sido eventualmente subestimada por razões técnicas, como utilização de dose sub-ótima ou perda da atividade biológica. Em relação ao Elispot para IFN-g, não pudemos observar diferenças entre os grupos, tanto quando se considerou o número total de spots, como quando se contou apenas spots com diâmetro > 65 mm, apresentando portanto uma sensibilidade aparentemente menor comparado aos outros 2 métodos. A comparação entre os métodos revelou pouca correlação entre seus resultados, que pode ser eventualmente explicado pela diferente contribuição das populações celulares (T CD4+ e T CD8+) para cada uma das provas munológicas. Finalmente, a análise da produção de IL-10 medida por Elisa no sobrenadante de cultura e por spots de IL10, também não revelou diferenças entre os grupos. Convém notar que o Elisa detectou baixas concentrações de IL-10 nos sobrenadantes, porém o Elispot demonstrou número elevado de spots e boa correlação entre as resposta aos antígenos. Em conclusão, nossos resultados sugerem que métodos \'clássicos\', e já estabelecidos, como linfoproliferação e Elisa, persistem válidos para se avaliar a imunidade celular, e que em nossas condições laboratoriais, a técnica de Elispot não representou, até o momento, uma melhora na qualidade da avaliação imunológica. / Tuberculosis is a chronic granulomatous disease characterized by a deficit of the antigen-specific immunity of the host, whose immune response is actively regulated by cytokines. In Brazil there are 50 million people infected with Mycobacterium tuberculosis. The objective of the present work was to evaluate the lymphoproliferative response e the IFN-g response by peripheral blood mononuclear cells (PBMC) indiced with 4 different antigens isolated from Mycobacterium tuberculosis: a complex, crude, the sonicate antigen, and 3 other, purified ones, Esat-6, 85B, and HBHA, the last 3 eventual candidates to the design of a vaccine against tuberculosis. We used 2 methods to evaluate the IFN-g and IL-10 productions, namely Elispot and Elisa of supernatant of PBMC cultures. We studied a group of active tuberculosis patients (TB-A), and compared them with controls individuals comprising 2 groups, one made of healthy PPD+ individuals and the second one of individuals who have been cured from an episode of tuberculosis in the past (TB-C). Our results of lymphoproliferation and Elisa revealed decrease in the lymphoproliferative and IFN-g responses by patients\' PBMC as compared to the PPD+ group, with the TB-C group in general presenting intermediate results. We also observed that the responses to the mitogen PHA were not statisically different among the groups, denoting the antigen-specific nature of the immune deficit in tuberculosis. In addition, we verified that stronger reactivity to the complex antigen than with the purified antigens, and, among the latter, the reactivity was stronger with Esat-6 and 85B as compared to HBHA, Reactivity to HBHA may have been understimated due to technical reasons, such as loss of .the biological activity of the molecule or use of a sub-optimal dose. By using the Elispot for IFN-g we were not able to detect differences among the groups, even when we counted all spots formed or spots with more than > 65 mm in diameter. Thus our Elispot for IFN-g apparently showed lower sensitivity than the other 2 methods. Furthermore, comparisons between the methods revealed low correlation between their results, a finding that may be explained by the differning contribution of different subpopulations (T CD4+ and T CD8+) to each of the results. Finally, analysis of the production of IL-10 as measured by Elisa in the culture supernatants as well as by Elispot revealed no differences among the groups. It is noteworthy that the levels of IL-10 detected by Elisa were low, but the Elispot revealed high number of spots and a good correlation between the antigen responses. In conclusion, we may say that our well standardized \'classical\' methods Elisa and lymphoproliferation persist useful to evaluate cellular immunity responses, and that the Elispot technique, up to now and in our laboratorial conditions, did not represent an improvement in the quality of the immunological evaluation.

Interferon regulatory factor-8 (Irf-8), a hematopoietic transcriptional regulator, controls myeloid-cell proliferation and coordinates innate and adaptive host immune responses. Mice from the BXH-2 recombinant inbred strain carry an endogenous R294C mutation in Irf-8. This loss-of-function mutation induces clonal infiltration of undifferentiated Mac-1+/Gr-1 + granulocytic precursors in BXH-2 mice, extramedullary hematopoiesis, and splenomegaly similar to those seen in human chronic myeloid leukemia. It also renders the host permissible to the otherwise avirulent Mycobacterium bovis (BCG), and negatively affects survival or recovery of these mice to other infectious pathogens. Here, we generated a polyc1onal anti-Irf-8 antibody to better characterize the effects of the R294C mutation on Irf-8 protein expression, stability, and inducibility in hematopoietic and non-hematopoietic tissues. We found that mutant Irf-8C294-expressing tissues consistently displayed reduced Irf-8 abundance compared to their wild-type counterparts in both primary splenocytes and following transfection into heterologous cells, presumably due to decreased stability or increased rate of degradation of the mutant isoform. Results also indicate that native Irf-8 is also expressed in the heart, and to a lesser extent, in the kidneys. Since neither of these organs is well-known to be associated with hematopoietic or immune functions, this finding strengthens the possibility that Irf-8 may exert additional regulatory functions in other cellular contexts. Taken together, our study provides a better understanding about the molecular features of the mutant Irf-8 C294 protein and contributes to a growing body of evidence in support of Irf-8 expression in non-hematopoietic tissues.

No description available.

O Fator de Necrose Tumoral-alfa (TNF-alfa) possui um importante papel na imunopatogênese da psoríase e agentes biológicos, como os inibidores de TNF-alfa, têm apresentado bons resultados no tratamento desta. No entanto, estes agentes foram associados ao aumento de casos de reativação de tuberculose entre os pacientes que os utilizaram. Este estudo foi realizado com o intuito de avaliar a resposta imune de pacientes com psoríase grave, ativa, sem tratamento, frente a antígenos de Mycobacterium tuberculosis (Mtb), e o efeito dos inibidores de TNF-alfa nesta resposta. Estudamos 24 pacientes com psoríase grave divididos em 2 grupos: não reatores (n = 14) e reatores (n = 10) ao teste intradérmico com PPD. Como controle, utilizamos um total de 26 indivíduos sadios, também separados em 2 grupos segundo a reatividade ao PPD (PPD-, n = 13; PPD+, n = 13). Em uma segunda etapa estudamos 11 pacientes com psoríase leve a moderada, também sem tratamento, PPD (-) para avaliarmos a importância da gravidade da psoríase na resposta aos antígenos micobacterianos. Avaliamos a resposta imunológica in vitro através da linfoproliferação, quantificação da produção de IFN-gama (ELISA) e quantificação de células produtoras de IFN-gama (ELISPOT), na presença e ausência dos inibidores de TNF-alfa (infliximab e etanercepte), utilizando os antígenos purificados ESAT-6, Ag85B e o antígeno bruto sonicado da cepa H37Rv (AgSMtb), e o mitógeno fitohemaglutinina (PHA). Os pacientes com psoríase grave PPD (-) apresentaram reposta linfoproliferativa e níveis de IFN-gama menores que nos controles PPD (-). Os pacientes com psoríase leve a moderada apresentaram resposta imune intermediária entre controles e pacientes graves. Em relação aos inibidores de TNF- alfa, verificou-se que infliximab e etanercepte apresentaram diferença em suas capacidades de inibição, sendo que somente o infliximab ocasionou a inibição total de TNF-alfa. Em contrapartida o etanercept manteve a produção de TNF-alfa, e em alguns casos elevou sua produção. Estes diminuíram apenas parcialmente a reatividade in vitro dos pacientes com psoríase, uma vez que a secreção de IFN-gama e o número de células produtoras de IFN-gama não foram alterados na presença dos inibidores. A secreção de IL-10 foi diminuída tanto na presença do infliximab, quanto na presença do etanercepte. Os dados obtidos permitem concluir que (a) os pacientes com psoríase grave PPD (-) apresentam uma baixa reatividade in vitro, principalmente das respostas que avaliam linfócitos T de memória central, aos antígenos de Mtb, sendo que essa baixa reatividade não está totalmente relacionada com a gravidade da doença, uma vez que os pacientes com psoríase leve a moderada apresentaram resposta intermediária a dos controles e pacientes com psoríase grave; (b) e que apesar dos inibidores de TNF- alfa promoverem uma inibição parcial da resposta imune, a reativação da tuberculose estaria mais relacionada à própria ausência de TNF-alfa, não compensada pela atuação isolada, e provavelmente insuficiente, de IFN-gama na manutenção do granuloma, do que a outras substanciais modificações na resposta imunológica frente aos antígenos micobacterianos. / Tumor necrosis factor alpha (TNF-alpha) has a pivotal role in psoriasis pathogenesis and biologic agents, such as TNF-alpha inhibitors, have provided good results in its treatment. However, the use of these agents has been associated with an increase in the number of cases of tuberculosis reactivation. This study aimed to evaluate the immune response of severe psoriasis patients, with active, untreated disease to relevant Mycobcterium tuberculosis antigens, and the effect of the TNF-alpha inhibitors (infliximab and etanercept) in this response. Twenty four severe psoriasis patients were enrolled and divided in two groups according to their reactivity to the tuberculin skin test: TST (n= 14) and TST + (n=10). As controls, we studied 26 healthy donors, also divided in two groups to the TST reactivity (TST -, n=13; TST+, n=13). Eleven mild to moderate psoriasis patients, untreated, TST (-) were studied to evaluated the role of psoriasis severity in the immune response to the mycobacterial antigens. Immune responses were evaluated in vitro by the lymphocyte proliferative response (LPR) assay, ELISA for IFN-? secretion by peripheral blood mononuclear cells and enumeration of IFN-? secreted cells (ELISPOT) induced in response to the purified antigens ESAT-6, Ag85B and a crude sonicated antigen preparation from H37Rv Mtb strain (AgSMtb), as well as to the mitogen phytohemagglutinin (PHA), in the presence or absenceinflimab/etanercept. The LPR and IFN-g secretion to Mtb antigens were lower in TST- severe psoriasis patients than TST- controls. Mild to moderate psoriasis patients had intermediate responses, between controls and severe psoriasis patients. The TNF-a inhibitors infliximab and etanercept showed differences in their inhibitiory activity, since only infliximab was capable to neutralize all TNF-a. On the other hand, etanercept kept TNF-alpha production, and in some cases even increased its production. The TNF-alpha inhibitors diminished partially the in vitro patients immune responses, since the IFN-? secretion and enumeration of IFN-? secreted cells were not affected. IL-10 secretion was diminished with both TNF-a inhibitors. In conclusion: (a) TST(-) severe psoriasis patients have decreased in vitro reactivity, mainly in those responses that evaluate central memory T-cell responses, to Mtb antigens, and this decrease could not be fully explained by disease severity, since mild psotiasis patients had intermediate responses; (b) and despite the fact that TNF-alpha inhibitors promote a partial immune response inhibition, tuberculosis reactivation could be related more with the lack of TNF-alpha, which was probably not compensated by the IFN-g activity alone, probably insufficient, to the support granuloma formation, than other defects of the immune response to Mtb antigens.

O Fator de Necrose Tumoral-alfa (TNF-alfa) possui um importante papel na imunopatogênese da psoríase e agentes biológicos, como os inibidores de TNF-alfa, têm apresentado bons resultados no tratamento desta. No entanto, estes agentes foram associados ao aumento de casos de reativação de tuberculose entre os pacientes que os utilizaram. Este estudo foi realizado com o intuito de avaliar a resposta imune de pacientes com psoríase grave, ativa, sem tratamento, frente a antígenos de Mycobacterium tuberculosis (Mtb), e o efeito dos inibidores de TNF-alfa nesta resposta. Estudamos 24 pacientes com psoríase grave divididos em 2 grupos: não reatores (n = 14) e reatores (n = 10) ao teste intradérmico com PPD. Como controle, utilizamos um total de 26 indivíduos sadios, também separados em 2 grupos segundo a reatividade ao PPD (PPD-, n = 13; PPD+, n = 13). Em uma segunda etapa estudamos 11 pacientes com psoríase leve a moderada, também sem tratamento, PPD (-) para avaliarmos a importância da gravidade da psoríase na resposta aos antígenos micobacterianos. Avaliamos a resposta imunológica in vitro através da linfoproliferação, quantificação da produção de IFN-gama (ELISA) e quantificação de células produtoras de IFN-gama (ELISPOT), na presença e ausência dos inibidores de TNF-alfa (infliximab e etanercepte), utilizando os antígenos purificados ESAT-6, Ag85B e o antígeno bruto sonicado da cepa H37Rv (AgSMtb), e o mitógeno fitohemaglutinina (PHA). Os pacientes com psoríase grave PPD (-) apresentaram reposta linfoproliferativa e níveis de IFN-gama menores que nos controles PPD (-). Os pacientes com psoríase leve a moderada apresentaram resposta imune intermediária entre controles e pacientes graves. Em relação aos inibidores de TNF- alfa, verificou-se que infliximab e etanercepte apresentaram diferença em suas capacidades de inibição, sendo que somente o infliximab ocasionou a inibição total de TNF-alfa. Em contrapartida o etanercept manteve a produção de TNF-alfa, e em alguns casos elevou sua produção. Estes diminuíram apenas parcialmente a reatividade in vitro dos pacientes com psoríase, uma vez que a secreção de IFN-gama e o número de células produtoras de IFN-gama não foram alterados na presença dos inibidores. A secreção de IL-10 foi diminuída tanto na presença do infliximab, quanto na presença do etanercepte. Os dados obtidos permitem concluir que (a) os pacientes com psoríase grave PPD (-) apresentam uma baixa reatividade in vitro, principalmente das respostas que avaliam linfócitos T de memória central, aos antígenos de Mtb, sendo que essa baixa reatividade não está totalmente relacionada com a gravidade da doença, uma vez que os pacientes com psoríase leve a moderada apresentaram resposta intermediária a dos controles e pacientes com psoríase grave; (b) e que apesar dos inibidores de TNF- alfa promoverem uma inibição parcial da resposta imune, a reativação da tuberculose estaria mais relacionada à própria ausência de TNF-alfa, não compensada pela atuação isolada, e provavelmente insuficiente, de IFN-gama na manutenção do granuloma, do que a outras substanciais modificações na resposta imunológica frente aos antígenos micobacterianos. / Tumor necrosis factor alpha (TNF-alpha) has a pivotal role in psoriasis pathogenesis and biologic agents, such as TNF-alpha inhibitors, have provided good results in its treatment. However, the use of these agents has been associated with an increase in the number of cases of tuberculosis reactivation. This study aimed to evaluate the immune response of severe psoriasis patients, with active, untreated disease to relevant Mycobcterium tuberculosis antigens, and the effect of the TNF-alpha inhibitors (infliximab and etanercept) in this response. Twenty four severe psoriasis patients were enrolled and divided in two groups according to their reactivity to the tuberculin skin test: TST (n= 14) and TST + (n=10). As controls, we studied 26 healthy donors, also divided in two groups to the TST reactivity (TST -, n=13; TST+, n=13). Eleven mild to moderate psoriasis patients, untreated, TST (-) were studied to evaluated the role of psoriasis severity in the immune response to the mycobacterial antigens. Immune responses were evaluated in vitro by the lymphocyte proliferative response (LPR) assay, ELISA for IFN-? secretion by peripheral blood mononuclear cells and enumeration of IFN-? secreted cells (ELISPOT) induced in response to the purified antigens ESAT-6, Ag85B and a crude sonicated antigen preparation from H37Rv Mtb strain (AgSMtb), as well as to the mitogen phytohemagglutinin (PHA), in the presence or absenceinflimab/etanercept. The LPR and IFN-g secretion to Mtb antigens were lower in TST- severe psoriasis patients than TST- controls. Mild to moderate psoriasis patients had intermediate responses, between controls and severe psoriasis patients. The TNF-a inhibitors infliximab and etanercept showed differences in their inhibitiory activity, since only infliximab was capable to neutralize all TNF-a. On the other hand, etanercept kept TNF-alpha production, and in some cases even increased its production. The TNF-alpha inhibitors diminished partially the in vitro patients immune responses, since the IFN-? secretion and enumeration of IFN-? secreted cells were not affected. IL-10 secretion was diminished with both TNF-a inhibitors. In conclusion: (a) TST(-) severe psoriasis patients have decreased in vitro reactivity, mainly in those responses that evaluate central memory T-cell responses, to Mtb antigens, and this decrease could not be fully explained by disease severity, since mild psotiasis patients had intermediate responses; (b) and despite the fact that TNF-alpha inhibitors promote a partial immune response inhibition, tuberculosis reactivation could be related more with the lack of TNF-alpha, which was probably not compensated by the IFN-g activity alone, probably insufficient, to the support granuloma formation, than other defects of the immune response to Mtb antigens.