<p>Patients with systemic lupus erythematosus (SLE) have an activated type I interferon (IFN) system with an ongoing IFN-α synthesis. This may be caused by circulating immune complexes, consisting of anti-DNA antibodies (Abs) and DNA, with IFN-α inducing capacity. Produced IFN-α may be crucial in the pathogenesis, because this cytokine can break tolerance and promote autoimmunity.</p><p>In the present thesis, possible mechanisms of the IFN-α production in SLE were studied. To investigate whether IFN-α inducing material could be derived from apoptotic cells, IgG from SLE patients (SLE-IgG) were combined with apoptotic cells. This combination induced high IFN-α production in normal peripheral blood mononuclear cells (PBMC). The IFN-α induction was associated to presence of anti-RNP Abs, but not to anti-dsDNA Abs, indicating that two inducers could be active in SLE, one containing DNA and the other RNA.</p><p>Apoptotic cells and SLE-IgG exclusively activated the natural interferon producing cells (NIPC) and the IFN-α response was enhanced by type I IFN and inhibited by IL-10 and TNF-α. The IFN-α induction was dependent on FcγRII, because blocking this receptor reduced IFN-α production and NIPC were found to express FcγRIIa.</p><p>To further elucidate the role of different autoantibodies in the IFN-α induction, sera from patients with Sjögren´s syndrome (SS), containing autoantibodies to RNA binding proteins (SSA, SSB, RNP and/or Sm) were investigated. The combination of SS or SLE sera and apoptotic or necrotic cell material induced high IFN-α production in PBMC. RNA, but not DNA, was required for IFN-α induction, indicating that RNA and Abs to RNA-binding proteins form potent IFN-α inducing complexes.</p><p>The findings in this thesis can explain central mechanisms for the activation of NIPC in SLE, and perhaps also other autoimmune diseases. This activation is mediated by interferogenic immune complexes, and modulating the NIPC activation may be a novel therapeutic approach in SLE.</p>

In sera remitted for anti-nuclear antibody (ANA) analysis, the supplement of a sensitive anti-SSA/Ro ELISA to the conventional ANA screening by immunofluorescence (IF) revealed that one fourth of the individuals with IF-ANA negative, but SSA/Ro ELISA positive sera, had systemic lupus erythematosus (SLE) or cutaneous LE. Consequently, adding a sensitive anti-SSA/Ro ELISA to the ANA screening is valuable for the serological detection of ANA negative SLE/LE patients. SLE patients often have measurable interferon-alpha (IFN-α) levels in serum, and IFN-α treatment of patients with non-autoimmune diseases can induce SLE. Thus, the type I IFN system seems to be important in SLE and was therefore investigated. Initially, a decreased IFN-α producing capacity, due to a 70-fold reduction in the number of circulating natural IFN-α producing cells (NIPC), was noted in peripheral blood mononuclear cells (PBMC) from SLE patients. SLE-sera contained an endogenous IFN-α inducing factor (SLE-IIF), consisting of IgG and DNA in the form of small immune complexes (300-1000 kD). The SLE-IIF selectively activated NIPC and was more common in sera from patients with active disease compared to individuals with inactive disease. IFN-α producing cells could be detected by immunohistochemistry in both lesional and unaffected skin from SLE patients, and IFN-α gene transcription could be verified by in situ hybridisation in some of the skin biopsies. A reduced number of NIPC, detected by expression of the blood dendritic cell antigen (BDCA)-2, was noted among SLE-PBMC. The IFN-α production triggered by SLE-IIF in SLE-PBMC was inhibited by monoclonal antibodies (mAbs) to BDCA-2 and markedly decreased by anti-BDCA-4 mAbs. The observations in the present thesis may explain the ongoing IFN-α production in SLE patients, indicate an important role for the activated type I IFN system in the pathogenesis, and suggest that direct targeting of SLE-NIPC may constitute a new therapeutic principle in SLE.

Patients with systemic lupus erythematosus (SLE) have an activated type I interferon (IFN) system with an ongoing IFN-α synthesis. This may be caused by circulating immune complexes, consisting of anti-DNA antibodies (Abs) and DNA, with IFN-α inducing capacity. Produced IFN-α may be crucial in the pathogenesis, because this cytokine can break tolerance and promote autoimmunity. In the present thesis, possible mechanisms of the IFN-α production in SLE were studied. To investigate whether IFN-α inducing material could be derived from apoptotic cells, IgG from SLE patients (SLE-IgG) were combined with apoptotic cells. This combination induced high IFN-α production in normal peripheral blood mononuclear cells (PBMC). The IFN-α induction was associated to presence of anti-RNP Abs, but not to anti-dsDNA Abs, indicating that two inducers could be active in SLE, one containing DNA and the other RNA. Apoptotic cells and SLE-IgG exclusively activated the natural interferon producing cells (NIPC) and the IFN-α response was enhanced by type I IFN and inhibited by IL-10 and TNF-α. The IFN-α induction was dependent on FcγRII, because blocking this receptor reduced IFN-α production and NIPC were found to express FcγRIIa. To further elucidate the role of different autoantibodies in the IFN-α induction, sera from patients with Sjögren´s syndrome (SS), containing autoantibodies to RNA binding proteins (SSA, SSB, RNP and/or Sm) were investigated. The combination of SS or SLE sera and apoptotic or necrotic cell material induced high IFN-α production in PBMC. RNA, but not DNA, was required for IFN-α induction, indicating that RNA and Abs to RNA-binding proteins form potent IFN-α inducing complexes. The findings in this thesis can explain central mechanisms for the activation of NIPC in SLE, and perhaps also other autoimmune diseases. This activation is mediated by interferogenic immune complexes, and modulating the NIPC activation may be a novel therapeutic approach in SLE.

Systemic lupus erythematosus (SLE) is the prototypic systemic autoimmune disease, whereas autoimmune polyendocrine syndrome type 1 (APS1) is a rare autosomal disorder characterized by combinations of organ-specific autoimmune manifestations including hypoparathyroidism and intestinal dysfunction, and may serve as a model for organ-specific autoimmunity. Autoantibodies directed against proteins expressed in the affected tissues are found in both diseases. From a chondrocyte cDNA expression library, we identified the protein AHNAK as an autoantigen in SLE. Anti-AHNAK antibodies were found in 29.5% (18/61) of patients with SLE, 4.6% (5/109) of patients with rheumatoid arthritis, and 1.2% (2/172) of blood donors. Using a candidate approach, we analyzed the prevalence in APS1 and other organ-specific autoimmune diseases, of autoantibodies against the pyridoxal phosphate-dependent enzymes histidine decarboxylase (HDC) and cysteine sulfinic acid decarboxylase (CSAD), which are structurally closely related to known autoantigens. Anti-HDC and anti-CSAD reactivity was detected exclusively in APS1 patient sera. Anti-HDC antibodies were detected in 37.1% (36/97) of the APS1 sera, did not cross-react with aromatic L-amino acid decarboxylase, and were associated with intestinal dysfunction and loss of histamine-producing gastric enterochromaffin-like cells. In contrast, anti-CSAD reactivity was detected in 3.6% (3/83) of APS1 sera and cross-reacted with recombinant glutamic acid decarboxylase. From a parathyroid cDNA expression library, novel spliced transcripts of the CLLD4 gene on human chromosome 13q14, encoding 26 and 31 kDa isoforms recognized by autoantibodies in 3.4% (3/87) of APS1 patients, were identified and found to be preferentially expressed in lung and ovary. Both isoforms contain an N-terminal BTB/POZ domain, similarly to the TNF-alpha-regulated protein B12, localize both to the cytoplasm and nucleus in transfected COS cells, and form oligomers in vitro. The CLLD4 gene is located in a region frequently deleted in several forms of cancer, including lung and ovarian tumors. In conclusion, we have identified and partially characterized AHNAK and HDC as two common targets of autoantibodies in SLE and APS1, respectively. We have also identified CSAD and CLLD4 as two minor autoantigens in APS1, one of which is a novel protein with unknown function.

Les anticorps anti-phospholipides (aPL), tels que les anticoagulants lupiques (LAC), sont associés au développement récurrent de thromboses chez les patients atteints du lupus érythémateux disséminé (LED). Il a été observé que des titres élevés d’auto-anticorps antilamine B1 (anti-LB1), chez des patients porteurs de LAC, diminuent le risque de ces manifestations thrombotiques. Toutefois, la relation existant entre la lamine B1 (LB1), les anti-LB1 et la thromboprotection n’est toujours pas expliquée. Dans cette étude, nous avons donc cherché à comprendre comment la LB1 et les anti-LB1 induisent cette thromboprotection. Nous avons testé les effets d'anti-LB1 purifiés et de LB1 recombinante sur l'activation des cellules endothéliales et des plaquettes. Nous avons été en mesure de déterminer que la LB1, contrairement aux anti-LB1, possède une activité anti-plaquettaire. En effet, la LB1 réduit l’activation et l’agrégation plaquettaires in vitro et in vivo. Cette activité est due à une liaison directe de la LB1 aux plaquettes, suivie par une internalisation rapide dans des vésicules de clathrine. Par co-immunoprécipitation, nous avons découvert que la LB1 interagit avec le récepteur de l’insuline situé sur la membrane plaquettaire. La liaison de la LB1 à ce récepteur entraîne vraisemblablement son internalisation et l'inhibition d'une des cascades de signalisation normalement induite par le récepteur de l’insuline, menant éventuellement à l’inhibition des fonctions plaquettaires. L’ajout d’anti-LB1 purifiés dans nos expériences a permis d'augmenter de façon significative la persistance de la LB1 dans les plaquettes, une observation confirmée par la détection de LB1 uniquement dans les lysats de plaquettes prélevées chez des patients anti-LB1 positifs. iv Nos résultats suggèrent que la LB1 prend part aux mécanismes régulateurs des processus d’hémostase chez des sujets sains et que la présence d’anti-LB1, chez les patients lupiques, prolonge la persistance de cet auto-antigène dans les plaquettes, les empêchant ainsi de s’activer. Ce mécanisme expliquerait la diminution du risque de thrombose chez les patients LAC positifs porteurs d’anti-LB1 circulants. / Anti-phospholipid antibodies such as lupus anticoagulant antibodies (LAC) are associated with recurrent thrombotic events in systemic lupus erythematosus (SLE) patients. However, the risk of thrombosis in LAC positive patients is markedly reduced in the presence of high titers of autoantibodies to lamin B1 (anti-LB1). To date, the implication of lamin B1 (LB1) and anti-LB1 in thromboprotection remains unclear. Our objective was to examine the mechanism whereby LB1 and anti-LB1 induced thromboprotection. Functional platelet and endothelial cell activation assays were used to determine the effects of recombinant LB1 and affinity purified anti-LB1 on these two cell types. LB1, contrarily to anti-LB1, was found to possess an intrinsic anti-platelet activity. This protein reduced the activation and aggregation of platelets in vitro and in vivo. This activity was likely due to the direct binding of LB1 to platelets, followed by its rapid internalization within clathrin coated-pits. Coimmunoprecipitation revealed that LB1 interacted with the insulin receptor located within the platelet membrane. The binding of LB1 to this receptor induced its internalization and inhibited at least one of the phosphorylation cascade stimulated by the receptor, which in turn inhibited platelet functions. The addition of affinity-purified anti-LB1 in our model markedly increased the persistence of LB1 within platelets, a finding supported by the detection of LB1 only in platelets from anti-LB1 positive SLE patients. Our results suggest that LB1 regulates haemostasis in normal subjects. The presence of anti-LB1 in SLE patients prolongs the persistence of LB1 within platelets, thus possibly vi preventing further platelet activation. This mechanism likely explains the reduced risk of thrombotic events in LAC positive SLE patients with circulating anti-LB1 autoantibodies.

Diss. (sammanfattning) Uppsala : Univ., 2009. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2009. / Härtill 4 uppsatser.

Introdução: O aumento da sobrevida dos pacientes com lúpus eritematoso sistêmico (LES) foi acompanhado por um aumento da frequência de comorbidades, tais como osteoporose e fraturas. Há descrições de associação de polimorfismos dos genes receptor ativador do fator nuclear kappa B (RANK), seu ligante (RANKL) e da osteoprotegerina (OPG) com alterações de densidade e fragilidade óssea, entretanto, não há estudos que avaliam estes polimorfismos em pacientes com LES. Objetivos: Avaliar polimorfismos de nucleotídeo único (SNP) dos genes RANKL, OPG e RANK em pacientes pré-menopausadas com LES e sua associação com densidade mineral óssea (DMO), fraturas vertebrais e concentrações séricas de sRANKL e OPG. Métodos: 211 mulheres com LES na pré-menopausa e 154 controles saudáveis foram avaliadas. Os seguintes SNPs foram avaliados por PCR em tempo real: RANKL [290 A > G (rs2277438)], OPG [1181 G > C (rs2073618), 245 T > G (rs3134069), 163 A>G (rs3102735)] e RANK [A > G (rs3018362)]. Concentrações séricas de OPG e sRANKL foram determinadas por ELISA, DMO e fraturas vertebrais por DXA (densitometria de dupla emissão com fonte de raios-X). Resultados: Pacientes e controles apresentaram frequência semelhante do alelo G do gene RANKL 290 A > G (41,2 vs. 40,3%, p=0,91), do alelo C do gene OPG 1181 G >C (62,6 vs. 61,0%, p=0,83), do alelo G da OPG 245 T>G (21,3 vs. 22,7%, p=0,80) do alelo G da OPG 163 A > G (96,2 vs. 87,0%, p=1,00) e do alelo G do RANK A > G (88,2 vs. 96,8%, p=0,75). Quando analisados os pacientes com LES, a frequência dos genótipos associados AG/GG do gene RANKL 290 A>G foi menos frequente em pacientes com fraturas vertebrais que em pacientes sem fraturas (28,1 vs. 46,9%, p=0,01). Com relação à densidade mineral óssea, a frequência dos genótipos associados TG/GG do polimorfismo 245 T > G da OPG foi maior em pacientes com baixa densidade mineral óssea do que em pacientes com densidade mineral óssea normal (31,4 vs. 18,1%, p=0,04). Não houve associação da DMO/fraturas com polimorfismos da OPG 1181 G > C, OPG 163 A > G e RANK A > G. Também não houve associação dos polimorfismos com as concentrações séricas de sRANKL e OPG. Conclusões: O presente trabalho demonstra pela primeira vez que variações genéticas no sistema OPG/RANKL podem desempenhar um papel importante na remodelação óssea e fratura em paciente pré-menopausadas com LES / Introduction: Survival rate improvement in systemic lupus erythematosus was accompanied by an increase in the incidence of long-term bone disorders such as osteoporosis, fractures and osteonecrosis. Polymorphisms of receptor activator of nuclear factor (NF)-kB ligand (RANKL) and osteoprotegerin (OPG) genes are known to influence bone mineral density and structure. However, there are no studies assessing these polymorphisms in SLE patients. Objective: To evaluate receptor activator of nuclear factor-kB (RANK) it ligand (RANKL) and osteoprotegerin (OPG) genes single nucleotide polymorphisms (SNP) in premenopausal SLE patients and their association with sRANKL and OPG serum levels, vertebral fractures and bone mineral density (BMD). Methods: 211 premenopausal SLE patients (ACR criteria) and 154 healthy controls were enrolled. SNPs of RANKL [290 A > G (rs2277438)], OPG [1181G > C (rs2073618), 245T>G (rs3134069), 163 A>G (rs3102735)] and RANK [A > G (rs3018362)] were obtained by real-time PCR. sRANKL/OPG serum levels were determined by ELISA. BMD and vertebral fractures were evaluated by dual energy X-ray absorptiometry. Results: SLE patients and controls had similar frequency of RANKL 290 G allele (41.2 vs. 40.3%, p=0.91), OPG 1181 C allele (62.6 vs. 61.0%, p=0.83), OPG 245 G allele (21.3 vs. 22.7%, p=0.80), OPG 163 G allele (96.2 vs. 87.0%, p=1.00) and RANK G allele (88.2 vs. 96.8%, p=0.75). Further analysis of SLE patients revealed that the frequency of RANKL 290 G allele was lower in patients with fractures than in patients without fractures (28.1 vs. 46.9%, p=0.01). In addition, the frequency of OPG 245 G allele was higher in patients with low BMD than in patients with normal BMD (31.4 vs. 18.1%, p=0.04). No association of OPG 1181 G > C, OPG 163 A > G and RANK A > G SNPs with BMD/fractures were found. Also, no association was observed between RANKL/OPG/RANK SNPs and sRANKL/OPG serum levels. Conclusions. Our study provides novel data demonstrating that RANKL/OPG genetic variations seem to play a role in bone remodeling and particularly in its main complication, fracture, in premenopausal patients with SLE

Made available in DSpace on 2014-07-29T15:29:19Z (GMT). No. of bitstreams: 1 dissertacao Dejan.pdf: 1549821 bytes, checksum: 1b164cc5ae65155bd615835e3ab66f19 (MD5) Previous issue date: 2009-09-17 / BACKGROUND: The Systemic Lupus Erythematosus (SLE) is an autoimmune disease that affects mainly women, and studies have shown that the use of immunosuppressants (IS) during SLE treatment may affect ovarian function. OBJECTIVES: This study aimed at the determination of possible associations in various IS therapeutic schemes and disturb in the ovarian function, through evaluation of menstrual cycle disturb and detection of premature ovarian failure in women with SLE. METHODS: A cross sectional study was conducted in 87 women, aged less than 40 years old that use IS in therapeutic scheme, as follows: prednisone, azathioprine, cyclophosphamide or methrotrexate, either alone or in a combination regime. The ovarian dysfunction was evaluated by the occurrence of menstrual disturbances such as hypermenorrhea, polymenorrhea, menorrhagia, oligomenorrhea, hypomenorrhea and amenorrhea and those diagnosed with premature ovarian failure. RESULTS: The values obtained by the study are expressed in years, mean and standard deviation. The age of the patients varied from 14 to 38 years old, with a mean age of 28.01 ± 5.81 years. The patients reached menarche between 10 and 19 years of age, with a mean age of 13.12 ± 1.77 years. The SLE diagnosis was established when the patients had between 10 and 35 years of age, with a mean age of 21.40 ± 5.75 years. When treatment is considered, 63.2% of the patients were being treated with of prednisone at the time of the study. The mean estradiol dosages used by eumenorrheic patients, patients that presented menstrual disturbances or in women with amenorrhea, was of 90.90 ± 120.78; 91.90 ± 64.77 and 115.97 ± 63.60; respectively, and the mean FSH dosages used by these same groups of patients was of 25.73 ± 34.46; 39.44 ± 59.82 and 54.40 ± 56.07; respectively. Menstrual disturbances were observed in 37.9% of the women evaluated, 11.5% of them had amenorrhea and 5.75% presented premature ovarian failure. There were no significant associations between the alterations in the menstrual cycle of the patients and the use of various dosages of IS and different therapeutic schemes. DISCUSSION: The data revealed that menstrual disturbances and premature ovarian failure were found in a higher frequency that found in the general population by other studies. However, they were similar to those found in previous studies conducted in women with SLE under IS therapy. The corticoids were the most administered drug and were used for the longest period of time, when compared to the other IS. Interestingly, the patients that were in use of corticoids had the highest frequency of menstrual alterations, when compared to the other patients, finding that disagrees with most of the studies from the literature. Among the multiple effects of corticoids in the human organism, are the hypothalamic and pituitary retro inhibitions, which may interfere with the ovaries functions. When treatment with the other IS is considered, it became evident that the lowest frequency of menstrual disturbances occurred in those patients treated with cyclophosphamide. Cumulative dose, age and appropriate duration of treatment could explain this finding. The use of anti-malaria drugs in more than half of the patients could have influenced the results. Additionally, variables in the pharmacological effects of the various drugs, the progression of the disease and multiple drug use could also explain our findings. CONCLUSION: Our data analysis is not sufficient to disregard the possible of risk factors associated with the development of ovarian dysfunction in the SLE women treated with immunossuppressants, when compared with the general population. In our understanding, treatment for SLE should be reevaluated, and future studies with focus on the understanding of the relationships between the SLE and ovarian function in the affected women, as well as on novel mechanisms that will contribute to preserve the ovarian function in these patients are of great importance. / INTRODUÇÃO: O lupus eritematoso sistêmico (LES) é uma doença autoimune que incide mais em mulheres, sendo que a doença e seu tratamento podem afetar a função ovariana. OBJETIVO: O estudo pretendeu buscar associação entre o tratamento com imunossupressores (IS) em pacientes com LES e alterações da função ovariana, medidas por meio das alterações no ciclo menstrual e da detecção de falência ovariana prematura (FOP). MÉTODOS: Corte transversal, incluindo 87 mulheres, com idades inferiores a 40 anos, submetidas ao tratamento com imunossupressores: prednisona, azatioprina, ciclofosfamida, ou metotrexato, em formulação única ou em associação. A disfunção ovariana foi determinada pela presença de alterações menstruais do tipo hipermenorréia, polimenorréia, menorragia, oligomenorréia, hipomenorréia, amenorréia e a falência ovariana prematura. RESULTADOS: Os valores são expressos em anos, média e desvio padrão. A idade das pacientes variou de 14 e 38 anos com a média de 28,01 ± 5,81 anos. As pacientes tiveram menarca registrada entre 10 e 19 anos, com média de idade 13,12 ± 1,77 anos, o diagnóstico de LES estabelecido entre 10 e 35, e a média de idade de 21,40 ± 5,75 anos. Quanto aos medicamentos, 63,2% dessas mulheres usavam a prednisona no momento do estudo. A dosagem de estradiol em pacientes eumenorreicas, com alterações menstruais e amenorreicas foi em média 90,90 ± 120,78; 91,90 ± 64,77 e 115,97 ± 63,60, respectivamente. A dosagem de FSH foi em média 25,73 ± 34,46; 39,44 ± 59,82 e 54,40 ± 56,07, respectivamente. As alterações menstruais foram observadas em 37,9% das mulheres examinadas, 11,5% tiveram amenorréia e 5,75% apresentaram falência ovariana prematura. As alterações do ciclo menstrual não tiveram associação significativa com o uso das diferentes formulações de imunossupressores. DISCUSSÃO: Alterações menstruais e falência ovariana prematura foram encontradas em frequência superior à população geral, mas semelhante a outras pesquisas com lúpicas usando imunossupressores. Os corticóides foram os medicamentos mais usados em número de pacientes e de tempo de uso, sendo que as que utilizaram esse imunossupressor apresentaram mais alterações menstruais, o que o diferencia da maioria das publicações. Pode-se aventar que além das múltiplas ações dos corticóides, destaca-se a retroinibição hipotalâmica e hipofisária com implicações para a função ovariana. Em relação aos outros IS ficou evidente a pouca frequência de alterações com a ciclofosfamida. Dose cumulativa, idade e tempo de uso adequado podem explicar esta verificação. O uso de antimaláricos em mais da metade das pacientes também pode ter influído nos resultados. Também variáveis de efeitos farmacológicos, evolução da doença e múltiplas drogas podem explicar diferentes resultados em relação a outras pesquisas. CONCLUSÃO: Os dados analisados não são suficientes para desconsiderarmos os fatores de risco associado com o desenvolvimento de alterações ovarianas em mulheres com lupus tratadas com IS quando comparadas com a população geral. É pertinente as pesquisas que orientem os processos terapêuticos ou a compreensão das relações entre o lupus eritematoso sistêmico e a função ovariana das mulheres afetadas com essa doença. Justifica-se, também, a busca de mecanismos que preservem a função ovariana.

O anticorpo anti-proteína P ribossomal é um dos marcadores sorológicos do lúpus eritematoso sistêmico, previamente associado a glomerulonefrite lúpica classe V (ISN-RPS). Neste trabalho foi avaliado o prognóstico renal em pacientes que possuem positividade para este anticorpo. Sessenta pacientes foram avaliados para parâmetros de sobrevida renal. Onze pacientes (18%) apresentaram positividade sorológica exclusiva para anticorpo anti-P ribossomal e vinte e oito pacientes (47%) para anti-dsDNA. Ao final do período de seguimento, foi observado que os pacientes anti-P positivos apresentaram uma maior sobrevida renal (11,0 ± 4,5 vs. 9,2 ± 4,5 anos, p=0,03) quando comparados aqueles anti-P negativos, assim como menor frequência de necessidade de terapia substitutiva renal (0 vs. 35% p = 0,025). Pacientes anti-P positivos apresentaram também maior frequência de classe V (91% vs. 31%, p < 0.001) e menor incidência de alterações proliferativas (45% vs. 82%, p = 0,021) na avaliação da biópsia renal quando comparados aos pacientes sem a positividade para este anticorpo. Os dados reforçam a hipótese de que o anticorpo anti-P é um marcador útil de um melhor prognóstico renal em pacientes portadores de lúpus eritematoso sistêmico / Antibodies to ribossomal P proteins are one of the serologic markers of systemic lupus erythematosus, previously described as associated to class V lupus glomerulonephritis (ISN-RPS). Our study assessed renal prognosis in patients with anti-P antibodies. Sixty consecutive SLE patients with biopsyproven nephritis (2004 ISN/RPS) were evaluated for renal survival parameters. Eleven patients (18%) had exclusive anti-P positivity and 28 (47%) patients anti-dsDNA. The post-biopsy follow-up analysis demonstrated that anti-P positive patients disclosed better renal survival (11.0 ± 4.5 vs. 9.2 ± 4.5 years, p = 0.03) as well as lower frequency of patients requiring dialysis (0 vs. 35% p = 0.025). The frequency of class V nephritis was higher in anti-P positive patients (91% vs. 31%, p < 0.001) and the occurrence of proliferative lesions at biopsy was lower in these patients (45% vs. 82%, p=0.021). Our data supports the notion that anti-P antibody is a valuable marker to predict a better long-term renal outcome in lupus patients