As gastroenterites ainda são um importante problema de saúde pública nos países em desenvolvimento e as Escherichia colí são as principais causas de diarréias. Adultos brasileiros apresentam anticorpos reativos com E. colí enteropatogênica (EPEC), que apresenta muitas semelhanças com E. colí enterohemorágica (EHEC) e pode ser responsável por complicações como a síndrome hemolítica urêmica e a colite hemorrágica. Ambas as bactérias apresentam um mecanismo patogênico comum: a formação da lesão \"attaching and effacing\" nos microvilus dos enterócitos, mediadas por fatores de virulência, como Intimina, Tir e as Esps. Os lipopolissacarídeos (LPS) são componentes da membrana externa das bactérias gram-negativas, incluindo E. colí. A infecção por EHEC 0157 resulta na produção de anticorpos séricos antiLPS 0157, que geralmente são indicativos de infecção recente. Neste trabalho, nós investigamos a presença de anticorpos séricos IgG e IgM anti-EHEC 0157:H7, EHEC 0111:H- e EPEC 0111:H- em adultos brasileiros, da Grande São Paulo. Amostras de soro foram coletadas de 200 adultos saudáveis, doadores de sangue, e um pool foi formado com 100 amostras. Anticorpos foram determinados em 100 amostras individuais por ELlSA com bactérias íntegras e anti-LPS para a determinação de anticorpos específicos anti-LPS 0111 e 0157 com o \"pool\" de soro como controle, em relação às concentrações de IgG e IgM totais determinadas simultaneamente. Os resultados foram submetidos a análise estatística. O repertório de anticorpos IgG e IgM para as três bactérias foi investigado por \"immunoblotting\" (18). A presença de anticorpos anti-bacterianos e anti-LPS foi confirmada. Existe uma correlação positiva entre os anticorpos reativos com as três bactérias, e entre os anticorpos anti-bactéria e anti-LPS. As concentrações de IgM anti-LPSs foi mais alta que IgG, o que está de acordo com o mecanismo imune esperado para um antígeno timo-independente. As concentrações de anti-LPS 0157 foram altas, apesar da baixa freqüência da bactéria 0157 em nosso meio. Os ensaios de 18 mostraram anticorpos reativos com bandas antigênicas sugestivas de fatores de virulência. A origem destes em nossa população poderia ser o contato com bactérias da microbiota ou do ambiente, de animais ou alimentos. Alternativamente, nossa população pode estar exposta à EHEC mais freqüentemente do que imaginado até agora. / Gastroenteritis is still an important public health problem in developing countries and Escherichia coli are frequent agents of diarrhea. Brazilian adults present antibodies reactive with the principal virulence factors of enteropathogenic E. coli (EPEC), which have many genetic and antigenic similarities with enterohemorrhagic E. coli (EHEC), that may be responsible for complications following diarrhea, as haemolytic uremic syndrome (HUS) and hemorrhagic colitis (HC). Both bacteria present a common pathogenic mechanism, with the formation of “attaching and effacing” lesion in microvilis’ enterocytes, mediated by virulence factors codified by the patogenicity island LEE, as Intimin, Tir e Esps. Lipopolysaccharides (LPS) are components of outer membrane and important virulence factors of Gram-negative bacteria including E. coli. The infection with EHEC O157 results in the production of serum antibodies to the O157 LPS antigens, and usually they are indicators of recent infection. In this work we investigated IgG and IgM serum antibodies reactive with EHEC O157:H7, EHEC O111:H- and EPEC O111:H- antigens in healthy Brazilian adults, living in São Paulo. Serum samples were collected from 200 healthy adults (blood donors) and a pool was formed with 100 samples. The antibody levels were determined by ELISA for 100 individual serum samples by means of a whole cell ELISA with the three bacteria and an anti-LPS ELISA for the determination of the concentrations of specific antibodies anti-LPS O111 and O157, using the serum pool as control, in relation to the total IgG and IgM concentrations determined simultaneously. The results were submitted to statistical analysis. The repertoire of IgG and IgM antibodies to the three bacteria was investigated by immunoblotting (IB). The presence of anti-bacterial and anti-LPS seric antibodies was confirmed. There is a positive correlation between the titers of antibodies reactive with the three bacteria and between anti-bacteria and anti-LPS antibodies. The concentrations of IgM anti-LPSs were significantly higher than IgG, which is in accordance with the immune mechanism expected to a thymus-independent antigen. Surprisingly the concentrations of anti-LPS O157 were high taking into account the low frequency of O157 bacteria isolation in our country. The IB assays showed the presence of antibodies, mainly IgG, reactive with many antigenic bands suggestive of virulence factors. The origin of anti-EHEC antibodies in our population could be the contact with microbiota or environment bacteria, and animal or human E. coli strains, pathogenic or not. Alternatively, our people may be exposed to EHEC more frequently than previously thought.

Lan is a high prevalence red blood cell antigen present in the majority of the populations that belong to the Lan (Langereis) blood group system. Anti-Lan antibody is an immunoglobulin G (IgG) antibody that is known to cause delayed hemolytic transfusion reactions in adults as well as hemolytic disease in fetuses and newborns, however with variable clinical significance ranging from mild to severe. We present a 58-year-old woman with diffuse abdominal pain and a large gastric ulcer causing gastric outlet obstruction. She underwent antrectomy and Billroth I reconstruction surgery without complications. The patient's hemoglobin upon presentation was 10g/dL and dropped acutely post-operatively to 6.4 g/dL requiring blood transfusion. The patient developed acute respiratory distress within minutes of starting a packed red blood cell (pRBC) transfusion, requiring discontinuation. Laboratory testing demonstrated pan-reactivity with additional reference testing demonstrating an anti-Lan antibody. The rarity of Lan negative pRBC units is a challenge in managing such patients requiring blood transfusions. Autologous blood donation or donation by a compatible family member is another option to consider in these rare cases.

<p>Cytomegalovirus (CMV) is a widespread infection affecting 50-90% of the human population. A typical silent primary infection is followed by life-long persistence in the host under control by virus-specific CD8 (“killer”) and CD4 (“helper”) T cells. Although harmless in most people, CMV may cause disease and sequelae in patients with deficient cellular immunity, such as AIDS patients, recipients of organ transplants and children who have acquired the virus before birth. In this thesis we have characterized the cellular immunity to CMV in immunocompetent subjects, in patients receiving transplants and in infants.</p><p>In healthy individuals with latent CMV, the frequencies of CMV-specific CD8 T cells varied considerably between the donors. Within the same individual, the changes over time were usually small. In patients with primary, symptomatic CMV infection, the frequencies of CMV-specific CD8 T cells peaked within the first month after the appearance of symptoms. The frequencies then declined to levels similar to those in latently infected CMV carriers. The CD4 T-cell function followed the same pattern, but with lower peak values.</p><p>Immunosuppressed renal transplant patients with latent CMV had CMV-specific CD4 cell function similar to healthy controls. The frequencies of CMV-specific CD8 T cells were also comparable, but their function was impaired. When renal transplant recipients were investigated longitudinally, we found that their CMV-specific T cells decreased rapidly after transplantation. Whereas the frequencies and function of CD8 T cells rebounded within 3 months, CD4 T-cell recovery was impaired during the entire first year after transplantation.</p><p>Finally, the frequencies and function of CMV-specific T-cells were investigated in children with congenital and postnatal CMV. CMV-specific CD8 T cells could be detected in even the youngest children, suggesting that these cells can develop early in life. In contrast, CMV specific CD4 T cells were low or absent in the youngest children but increased slowly with age.</p>

The present thesis focuses on Czech allergology and clinical immunology by studying this branch of health care in a geographic variation framework while using methods of spatial econometrics. This has been the first work with such focus. District-level data on care provision and utilization in 2012 are used. It is found that there exist geographical differences between provision and utilization and that the geographical distribution of allergists and clinical immunologists does not correspond to population's needs. Care utilization is modeled using a spatial autoregressive model specification. Based on this model, it is concluded that a shortage of physicians in the majority of districts actually limits care utilization. Also based on the utilization model, there is a discussion about the potential need for policy coordination. Care provision cannot be modeled using explanatory variables that are available, therefore, future data collection is necessary. However, it was found that variables influencing the need for care by patients do not influence care provision per physician. JEL Classification I11, I14, I19 Keywords geographic variation, Czech, allergology, clinical immunology, ACI, spatial model Author's e-mail 18702440@fsv.cuni.cz Supervisor's e-mail michal.paulus@fsv.cuni.cz

A diarréia é um importante problema de saúde pública no mundo inteiro e a Escherichia coli é um dos mais freqüentes microorganismos causadores desta doença. A Escherichia coli enteropatogênica (EPEC), um dos principais agentes etiológicos das diarréias infantis no nosso país, é genética e fenotipicamente relacionada com a E. coli enterohemorrágica (EHEC) que além de provocar diarréia é responsável por complicações como síndrome hemolítica urêmica (HUS) e colite hemorrágica (HC). Embora a EHEC seja considerada emergente pela OMS, no Brasil poucos casos de complicações como HUS e HC foram reportados. O mecanismo de patogenicidade comum entre EPEC e EHEC é conhecido como a lesão \"attaching and effacing\" nos microvilos do enterócito. Esta lesão é mediada por um conjunto de fatores de virulência, dentre eles a intimina. A intimina é uma proteína de membrana externa, responsável pelo íntimo contato da bactéria com o enterócito, possui uma região N-terminal que é altamente conservada e uma região C-terminal que é variável. De acordo com a região variável, existem vários subtipos de intimina, dentre eles as intiminas &#945; &#946; e &#947;. Uma infecção por EPE-C ou EHE-C induz a uma resposta de anticorpos anti-intimina no soro e no colostro. No presente trabalho, foram determinados os anticorpos contra as regiões variáveis &#945; &#946; e &#947; e a região conservada em 100 amostras de soro e em 54 colostros de adultos saudáveis da Grande São Paulo. As concentrações de IgG sérico e de IgA secretora foram determinadas por ELISA utilizando como antígeno proteínas purificadas obtidas de bactérias recombinantes de cada intimina e os resultados foram submetidos a análise estatística. Foram também realizadas absorções com as bactérias recombirrantes e ensaios de inibição de adesão. Primeiramente observamos que nossa população apresenta anticorpos séricos e secretores reativos com a região conservada e as regiões variáveis das intiminas &#945; &#946; e &#947;, e que existe uma correlação positiva entre os, diferentes grupos de dados, mostrando assim uma reatividade cruzada parcial entre os anticorpos anti-intiminas, este fato foi confirmado com as absorções e com os ensaios de adesão. A concentração de anticorpos IgA no colostro é mais alta que IgG no soro e a concentração de anticorpos anti-região conservada da intimina no soro se encontra elevada quando comparada com as outras três determinações. Em ensaio de adesão em células HEp-2, foi verificado que anticorpos anti-região variável inibem a adesão de EPEC 0127:H6 numa porcentagem maior que os anticorpos anti-região conservada. Apresença de anticorpos anti-região variável da intimina &#947; sugere mais uma vez a possível proteção contra a EHEC. Em conjunto, nossos resultados corroboram com a idéia de que nossa população desenvolve uma imunidade natural resultante da exposição a linhagens de E. Coli ou outras bactérias presentes no ambiente, que confere uma proteção contra. EHEC, mesmo não sendo esta bactéria tão freqüente no nosso meio. / Enteropathogenic Escherichia coli (EPEC) is a leading cause of infantile diarrhea in developing countries, and has many genetic and antigenic similarittes with enterohaemorrhagic Escherichia coli (EHEC). EHEC can cause a variety of uman illnesses ranging from uncomplicated diarrhea to haemorrhagic colitis and haemolytic uremic syndrome. EHEC strains share with EPEC the ability to induce the attaching and effacing lesion (A/E) onto the human enterocyte membrane mediated by virulence factors codified by the patogenicity island LEE, as the type III secretion system, Esps, intimin and Tir. The infection with EPEC and EHEC induces the production of antibodies reactive with these virulence factors. Intimin is an outer membrane protein that mediates intimate attachment in the host cells, upon interaction with its- translocated receptor Tir. This protein shows high conservationin the N-terminal region and variability in the last C-terminal 280 amino acids. Many subtypes of intimins, like &#945;, &#946; and &#947;, were described according to the variable region. In this work we determined the concentration of IgG antibodies in 100 serum samples and IgA antibodies in 54 colostrum samples reactive with the variable regions &#945;, &#946; and &#947; intimins and the conserved region in healthy Brazilian adutts, living in São Paulo. The concentrations of seric IgG and secretor IgA anti-intimin antibodies were determined by ELISA with purified proteins obtained from recombinant bacteria expressing the conserved and the variable regions, and then the results were submitted to statistical analysis. Some absorptions and adhesion assays were performed with the aim of investigate cross reactions among the various antibodies. Firstly we observed that our poputation has seric and secretory antibodies reactive with conserved and variable regions of &#945;, &#946; and &#947; intimins, and there are a positive correlation among these antibodies in serum and colostrum, showing a partial cross reactivity among anti-intimins antibodies. This was confirmed by the absorptions and adhesion assays. IgA antibodies in colostrum were higher than IgG in serum, what could be related with the profective effect of breastfeeding against EPEC infection in infants. The seric antibodies anti-conserved region were higher compared to the other three determinations. The results obtained in the adhesion assays showed that the percentage of inhibition adhesion to EPEC 0127:H6 serotype with anti-variable regions antibodies was higher than anti-conserved regions. The presence of anti-&#947; variable region suggests the possible protection against EHEC. Taken together, our results suggest that our population develop a natural immunity as a result of the direct contact with E. coli strains or other bacteria present in the environment, which confers protection against EHEC, although it is not frequent in our population.

Cytomegalovirus (CMV) is a widespread infection affecting 50-90% of the human population. A typical silent primary infection is followed by life-long persistence in the host under control by virus-specific CD8 (“killer”) and CD4 (“helper”) T cells. Although harmless in most people, CMV may cause disease and sequelae in patients with deficient cellular immunity, such as AIDS patients, recipients of organ transplants and children who have acquired the virus before birth. In this thesis we have characterized the cellular immunity to CMV in immunocompetent subjects, in patients receiving transplants and in infants. In healthy individuals with latent CMV, the frequencies of CMV-specific CD8 T cells varied considerably between the donors. Within the same individual, the changes over time were usually small. In patients with primary, symptomatic CMV infection, the frequencies of CMV-specific CD8 T cells peaked within the first month after the appearance of symptoms. The frequencies then declined to levels similar to those in latently infected CMV carriers. The CD4 T-cell function followed the same pattern, but with lower peak values. Immunosuppressed renal transplant patients with latent CMV had CMV-specific CD4 cell function similar to healthy controls. The frequencies of CMV-specific CD8 T cells were also comparable, but their function was impaired. When renal transplant recipients were investigated longitudinally, we found that their CMV-specific T cells decreased rapidly after transplantation. Whereas the frequencies and function of CD8 T cells rebounded within 3 months, CD4 T-cell recovery was impaired during the entire first year after transplantation. Finally, the frequencies and function of CMV-specific T-cells were investigated in children with congenital and postnatal CMV. CMV-specific CD8 T cells could be detected in even the youngest children, suggesting that these cells can develop early in life. In contrast, CMV specific CD4 T cells were low or absent in the youngest children but increased slowly with age.

A diarréia é um importante problema de saúde pública no mundo inteiro e a Escherichia coli é um dos mais freqüentes microorganismos causadores desta doença. A Escherichia coli enteropatogênica (EPEC), um dos principais agentes etiológicos das diarréias infantis no nosso país, é genética e fenotipicamente relacionada com a E. coli enterohemorrágica (EHEC) que além de provocar diarréia é responsável por complicações como síndrome hemolítica urêmica (HUS) e colite hemorrágica (HC). Embora a EHEC seja considerada emergente pela OMS, no Brasil poucos casos de complicações como HUS e HC foram reportados. O mecanismo de patogenicidade comum entre EPEC e EHEC é conhecido como a lesão \"attaching and effacing\" nos microvilos do enterócito. Esta lesão é mediada por um conjunto de fatores de virulência, dentre eles a intimina. A intimina é uma proteína de membrana externa, responsável pelo íntimo contato da bactéria com o enterócito, possui uma região N-terminal que é altamente conservada e uma região C-terminal que é variável. De acordo com a região variável, existem vários subtipos de intimina, dentre eles as intiminas &#945; &#946; e &#947;. Uma infecção por EPE-C ou EHE-C induz a uma resposta de anticorpos anti-intimina no soro e no colostro. No presente trabalho, foram determinados os anticorpos contra as regiões variáveis &#945; &#946; e &#947; e a região conservada em 100 amostras de soro e em 54 colostros de adultos saudáveis da Grande São Paulo. As concentrações de IgG sérico e de IgA secretora foram determinadas por ELISA utilizando como antígeno proteínas purificadas obtidas de bactérias recombinantes de cada intimina e os resultados foram submetidos a análise estatística. Foram também realizadas absorções com as bactérias recombirrantes e ensaios de inibição de adesão. Primeiramente observamos que nossa população apresenta anticorpos séricos e secretores reativos com a região conservada e as regiões variáveis das intiminas &#945; &#946; e &#947;, e que existe uma correlação positiva entre os, diferentes grupos de dados, mostrando assim uma reatividade cruzada parcial entre os anticorpos anti-intiminas, este fato foi confirmado com as absorções e com os ensaios de adesão. A concentração de anticorpos IgA no colostro é mais alta que IgG no soro e a concentração de anticorpos anti-região conservada da intimina no soro se encontra elevada quando comparada com as outras três determinações. Em ensaio de adesão em células HEp-2, foi verificado que anticorpos anti-região variável inibem a adesão de EPEC 0127:H6 numa porcentagem maior que os anticorpos anti-região conservada. Apresença de anticorpos anti-região variável da intimina &#947; sugere mais uma vez a possível proteção contra a EHEC. Em conjunto, nossos resultados corroboram com a idéia de que nossa população desenvolve uma imunidade natural resultante da exposição a linhagens de E. Coli ou outras bactérias presentes no ambiente, que confere uma proteção contra. EHEC, mesmo não sendo esta bactéria tão freqüente no nosso meio. / Enteropathogenic Escherichia coli (EPEC) is a leading cause of infantile diarrhea in developing countries, and has many genetic and antigenic similarittes with enterohaemorrhagic Escherichia coli (EHEC). EHEC can cause a variety of uman illnesses ranging from uncomplicated diarrhea to haemorrhagic colitis and haemolytic uremic syndrome. EHEC strains share with EPEC the ability to induce the attaching and effacing lesion (A/E) onto the human enterocyte membrane mediated by virulence factors codified by the patogenicity island LEE, as the type III secretion system, Esps, intimin and Tir. The infection with EPEC and EHEC induces the production of antibodies reactive with these virulence factors. Intimin is an outer membrane protein that mediates intimate attachment in the host cells, upon interaction with its- translocated receptor Tir. This protein shows high conservationin the N-terminal region and variability in the last C-terminal 280 amino acids. Many subtypes of intimins, like &#945;, &#946; and &#947;, were described according to the variable region. In this work we determined the concentration of IgG antibodies in 100 serum samples and IgA antibodies in 54 colostrum samples reactive with the variable regions &#945;, &#946; and &#947; intimins and the conserved region in healthy Brazilian adutts, living in São Paulo. The concentrations of seric IgG and secretor IgA anti-intimin antibodies were determined by ELISA with purified proteins obtained from recombinant bacteria expressing the conserved and the variable regions, and then the results were submitted to statistical analysis. Some absorptions and adhesion assays were performed with the aim of investigate cross reactions among the various antibodies. Firstly we observed that our poputation has seric and secretory antibodies reactive with conserved and variable regions of &#945;, &#946; and &#947; intimins, and there are a positive correlation among these antibodies in serum and colostrum, showing a partial cross reactivity among anti-intimins antibodies. This was confirmed by the absorptions and adhesion assays. IgA antibodies in colostrum were higher than IgG in serum, what could be related with the profective effect of breastfeeding against EPEC infection in infants. The seric antibodies anti-conserved region were higher compared to the other three determinations. The results obtained in the adhesion assays showed that the percentage of inhibition adhesion to EPEC 0127:H6 serotype with anti-variable regions antibodies was higher than anti-conserved regions. The presence of anti-&#947; variable region suggests the possible protection against EHEC. Taken together, our results suggest that our population develop a natural immunity as a result of the direct contact with E. coli strains or other bacteria present in the environment, which confers protection against EHEC, although it is not frequent in our population.

A Imunodeficiência de Variável Comum (ICV) é caracterizada por baixos níveis de imunoglobulinas com susceptibilidade a. Analisamos a distribuição de linfócitos, apoptose espontânea e a expressão gênica de receptores de morte, ligantes, adaptadores, moléculas reguladoras, inibidoras e anti-apotóticas em células CD4+ e CD8+ de 19 pacientes ICV e 19 controles. Pacientes com ICV apresentam diminuição na frequência de linfócitos TCD4+ e CD4+CD45RA+ e menor relação CD4/CD8 que indivíduos saudáveis. O grupo de pacientes mostrou maior frequência de apoptose espontânea em linfócitos totais e CD4+. Células CD4+ dos indivíduos afetados apresentaram menor expressão gênica de TRAIL-R, BCL-2, FLIPL e FADD; células CD8+ apresentaram diminuição da expressão gênica de TRAIL, FADD, BCL-2, BCL -xL e um aumento de FLIPs. Os resultados sugerem um desequilíbrio nos mecanismos que controlam a apoptose de linfócitos nestes pacientes, o que pode ajudar a elucidar as alterações observadas no compartimento de células T dos pacientes com ICV. / Common Variable Immunodeficiency (CVID) is is characterized by low immunoglobulins levels with susceptibility to infections. We have analyzed T cell distribution and spontaneous apoptosis in peripheral blood of CVID, as well as gene expression of several molecules involved in apoptosis, including death receptors, ligands, adapters, regulatory and anti-apototic molecules in CD4+ and CD8+ cells of 19 CVID patients and 19 healthy subjects. CVID subjects present decreased frequency of TCD4+ and CD4+ CD45RA+ cells and lower CD4/CD8 ratio than healthy controls. CVID group also presented higher frequency of spontaneous apoptosis in lymphocytes and CD4+ cells. CD4+ showed lower expression of TRAIL-R, BCL-2, FLIPL and FADD; CD8+ cells presented lower expression of TRAIL, FADD, BCL-2, BCL-xL and a augment of FLIP. Results suggest an imbalance in mechanisms controlling cell death of those patients lymphocytes, which might help to elucidate the changes observed in T cell compartment of CVID patients.

Several studies have shown that complement and thrombotic events co-exist. Platelets have been suspected to act as the bridge between the two cascade systems. To study the platelet-induced complement activation we developed a system in which platelets were activated by thrombin receptor activating peptide (TRAP) in platelet rich plasma (PRP) or whole blood anti-coagulated using the specific thrombin inhibitor, lepirudin. TRAP-activated platelets induced a fluid-phase complement activation measured as generation of C3a and sC5b-9, triggered by released chondroitin sulphate-A (CS-A) which interacted with C1q and activated the complement system through the classical pathway. Complement components C1q, C3, C4 and C9 were also shown to bind to TRAP-activated platelets but this binding did not seem to be due to a complement activation since blocking of complement activation at the C1q or C3 levels did not affect the binding of the complement proteins. The C3 which bound to activated platelets consisted of C3(H2O), indicating that bound C3 was not proteolytically activated. Binding of C1q was partially dependent on CS-A exposure on activated platelets. The abolished complement activation on the surface of activated platelets was suggested to be dependent on the involvement of several complement inhibitors. We confirmed the binding of C1INH and factor H to activated platelets. To this list we have added another potent complement inhibitor, C4BP. The binding of factor H and C4BP was shown to be dependent on exposure of CS-A on activated platelets. The physiological relevance of these reactions was reflected in an elevated expression of CD11b on leukocytes, and increased generation of platelet-leukocyte complexes. The platelets were involved in these events by at least two different mechanisms; generation of C5a which activated leukocytes and binding of C3(H2O)/iC3(H2O), a ligand to the intergrin CD11b/CD18 on their surface. These mechanisms add further to the understanding of how platelets interact with the complement system and will help us to understand the role of the complement system in cardiovascular disease and thrombotic conditions. / Platelet Mediated Complement Activation

A Imunodeficiência de Variável Comum (ICV) é caracterizada por baixos níveis de imunoglobulinas com susceptibilidade a. Analisamos a distribuição de linfócitos, apoptose espontânea e a expressão gênica de receptores de morte, ligantes, adaptadores, moléculas reguladoras, inibidoras e anti-apotóticas em células CD4+ e CD8+ de 19 pacientes ICV e 19 controles. Pacientes com ICV apresentam diminuição na frequência de linfócitos TCD4+ e CD4+CD45RA+ e menor relação CD4/CD8 que indivíduos saudáveis. O grupo de pacientes mostrou maior frequência de apoptose espontânea em linfócitos totais e CD4+. Células CD4+ dos indivíduos afetados apresentaram menor expressão gênica de TRAIL-R, BCL-2, FLIPL e FADD; células CD8+ apresentaram diminuição da expressão gênica de TRAIL, FADD, BCL-2, BCL -xL e um aumento de FLIPs. Os resultados sugerem um desequilíbrio nos mecanismos que controlam a apoptose de linfócitos nestes pacientes, o que pode ajudar a elucidar as alterações observadas no compartimento de células T dos pacientes com ICV. / Common Variable Immunodeficiency (CVID) is is characterized by low immunoglobulins levels with susceptibility to infections. We have analyzed T cell distribution and spontaneous apoptosis in peripheral blood of CVID, as well as gene expression of several molecules involved in apoptosis, including death receptors, ligands, adapters, regulatory and anti-apototic molecules in CD4+ and CD8+ cells of 19 CVID patients and 19 healthy subjects. CVID subjects present decreased frequency of TCD4+ and CD4+ CD45RA+ cells and lower CD4/CD8 ratio than healthy controls. CVID group also presented higher frequency of spontaneous apoptosis in lymphocytes and CD4+ cells. CD4+ showed lower expression of TRAIL-R, BCL-2, FLIPL and FADD; CD8+ cells presented lower expression of TRAIL, FADD, BCL-2, BCL-xL and a augment of FLIP. Results suggest an imbalance in mechanisms controlling cell death of those patients lymphocytes, which might help to elucidate the changes observed in T cell compartment of CVID patients.