Podocitopatía lúpica / Lupus podocytopathy

El lupus eritematoso sistémico (LES) es una enfermedad sistémica autoinmune que puede afectar a múltiples órganos. Aproximadamente el 50% de los pacientes con LES desarrollan enfermedad renal clínicamente evidente, la cual es una causa importante de morbimortalidad. El síndrome nefrótico (SN) es frecuente en los pacientes con nefritis lúpica (NL) y usualmente se asocia a depósitos de complejos inmunes en las paredes capilares, acompañados de proliferación endocapilar y necrosis. No obstante, existe un número creciente de casos reportados de pacientes con LES y SN cuyas biopsias se caracterizan por injuria podocitaria, consistente en fusión pedicelar en la microscopía electrónica y un patrón morfológico idéntico a la enfermedad por cambios mínimos (ECM), a la esclerosis focal y segmentaria primaria o a una glomerulonefritis proliferativa mesangial, en ausencia de depósitos inmunes en las paredes capilares. Este hallazgo podría deberse a la coexistencia de NL y ECM, sin embargo, la mayoría de las investigaciones consideran que esto no es una mera coincidencia. De allí surge una nueva entidad, la "podocitopatía lúpica", patología posiblemente mediada por la activación de células T y la presencia de un factor de permeación glomerular. Esto permite diferenciar al grupo de pacientes con LES y SN, que en la biopsia carecen de depósitos inmunes en las paredes capilares o de signos de actividad lúpica renal, se evidencia fusión pedicelar difusa en la ME y presentan además una alta sensibilidad al tratamiento con corticoides. El diagnóstico de esta nueva entidad, requiere de la interpretación de los hallazgos histopatológicos con la correcta integración de los datos de la inmunofluorescencia y la microscopía electrónica

Lupus Erythematosus (SLE) is a systemic autoimmune disease which may affect several organs. Approximately 50% of SLE patients develop clinically overt renal disease, an important cause of morbidity and mortality. Nephrotic syndrome (NS) is frequent in patients suffering from lupus nephritis (LN) and it is usually associated with immune complex deposition on capillary walls accompanied by endocapillary proliferation and necrosis. However, a growing number of reported cases of SLE and NS patients show biopsies which reveal podocyte injury, consisting of pedicel fusion upon electron microscopy and a morphological pattern identical to minimal change disease (MCD), primary focal segmental glomerulosclerosis or mesangial proliferative glomerulonephritis, in absence of immune complex deposition on capillary walls. Although this finding could be explained by the coexistence of LN and MCD, most researchers consider that this fact is not pure coincidence. A new term, lupus podocytopathy, therefore appears to define a distinct entity characterized by T cell activation and the presence of a glomerular permeability factor. This allows to distinguish the group of SLE and NS patients whose biopsies do not show immune complex deposition on capillary walls or signs of renal lupus activity; electron microscopy reveals diffuse pedicel fusion and patients show high responsiveness to corticosteroid treatment. In order to diagnose this new entity, it is necessary to interpret histopathological findings together with data gathered from immunofluorescence and electron microscopy

Associação entre anticorpos antifosfolípides e fator reumatóide empacientes com nefrite lúpica: um estudo de 187 casos / Associatiom between antiphospholipid antibodies and rheumatoid factor in patients with Lupus Nephrits: a study of 187 cases

Introdução: Nefrite é uma manifestação freqüente no lúpus eritematoso sistêmico (LES), tendo uma prevalência de 40 a 75%. Embora esteja associada com a ocorrência de anticorpo anti-DNA, outros autoanticorpos podem estar ligados ao seu aparecimento taiscomo o fator reumatóide (FR) e os anticorpos antifospholípides (aPl).Objetivos: verificar a prevalência de nefrite lúpica local e sua associação com o a presença do FR e aPls. Métodos: Revisaram-se 187 prontuários depacientes com LES para presença de nefrite, FR e aPl . Resultados: Encontrou-se uma prevalência de 35,3% de glomerulonefrite. Houve correlação negativa entre nefrite e FR (p=0.001). Não se encontrou associação entre aparecimento de aPl e nefrite, já queo número de pacientes com glomerulonefrite que apresentaram esses testes positivos foram de 8 (32%)em 59; 5 (27,7%) em 58 e 6 (46,1%) em 29, respectivamente. Conclusão: Existe uma prevalência de 35% denefrite na população local de LES a qual tem uma associação negativa com aparecimento do FR. Presença de aPls não influíram no aparecimento da nefrite lúpica.

Summary: Nephritis is a frequent manifestation of systemic lupus erythematosus (SLE), with an averageof 40 to 75%. It’s associated with the presence of anti-DNA antibodies;other antibodies may also be involved,such as rheumatoid factor (RF), and antiphospholipid antibodies (aPl).Objectives: to verify the prevalence of lupus nephritis and its association with RF and aPl antibodies. Methods: The charts of 187 patients with SLE werereviewed for the presence of nephritis, RF and aPl. Results: A prevalence of 35.3% of nephritis was found. There was a negative correlation betweennephritis and presence of rheumatoid factor (p=0,001). No association between the presence of aPl and nephritis was found, since the number of patients with glomerulonephritis that were positive for these tests wasof 8 (32%) in 59, 5 (27,77%) in 58 and 6 (46,1%) in 29, respectively.Conclusion: There is a prevalence ofglomerulonephritis of 35% in the local SLE population, which has a negative association with rheumatoid factorpresence. Antiphospholipid antibodies aren’t associated to the occurrence of lupus nephritis.