Antibodies to ribosomal P proteins: A potential serologic marker for lupus membranous glomerulonephritis

Abstract

Objective. To evaluate the relevance of antibodies to ribosomal P proteins (anti-P antibodies) in discriminating histopathologic patterns of lupus nephritis.Methods. The study group comprised 81 consecutive patients with systemic lupus erythematosus who underwent renal biopsy and for whom frozen serum was available at the time of biopsy. All biopsy specimens were reviewed in a blinded manner, according to the 2004 criteria of the International Society of Nephrology and the Renal Pathology Society. Anti-P antibodies were detected by enzyme-linked immunosorbent assay (ELISA)/immunoblot analysis, and anti-doublestranded DNA (anti-dsDNA) was detected by indirect immunofluorescence/ELISA.Results. Anti-P antibodies were detected in 18 patients (22%). The demographic and clinical features of patients with and those without anti-P antibodies were similar. Remarkably, analyses of biopsy specimens revealed that the frequency of anti-P antibodies in patients with class V lupus nephritis was higher than the frequency among patients with other classes of renal disease (72% versus 28%; P ‫؍‬ 0.005). Accordingly, anti-P antibody-positive patients had a higher mean (؎SD) proteinuria level compared with anti-P antibodynegative patients (6.4 ؎ 4.8 versus 4.7 ؎ 3.9 gm/dl; P ‫؍‬ 0.046). Renal function was preserved in 6 of 7 patients who had both isolated anti-P antibodies and class V lupus nephritis. In contrast, anti-dsDNA was associated with proliferative-class lupus nephritis (P ‫؍‬ 0.050) and higher creatinine levels (P ‫؍‬ 0.014). Furthermore, 7 of 9 patients with isolated anti-P antibodies had class V lupus nephritis, and, more importantly, 5 of these 7 patients (71%) displayed a pure membranous pattern. Conversely, a tendency toward the predominance of class V lupus nephritis (67%) with concomitant proliferative lesions was observed when anti-P antibody was associated with anti-dsDNA.Conclusion. Our data introduce anti-P antibody as a novel serologic marker for membranous lupus nephritis and support the notion that the presence of isolated anti-P antibodies may discriminate patients with pure class V lupus nephritis, whereas the simultaneous presence of anti-dsDNA antibodies suggests class V disease with concomitant proliferative lesions.Renal disease remains a major cause of morbidity in patients with systemic lupus erythematosus (SLE), and end-stage renal disease will develop in ϳ10-30% of patients with SLE. Anti-double-stranded DNA (antidsDNA) is strongly associated with active nephritis; however, the presence of these antibodies is not mandatory for renal tissue damage.Therefore, it is of great interest to study other antibodies that may be associated with lupus nephritis. A retrospective case-control study correlated antibodies to P ribosomal proteins (anti-P antibodies) with renal disease (1), and this observation was further supported by the finding of an association of anti-P antibodies with

Estudo longitudinal do anticorpo antilipoproteína lipase e sua relação com atividade de doença nos indivíduos com lúpus eritematoso sistêmico sem anticorpos anti-dsDNA

“…Our group has demonstrated in previous work, the association of anti-ribosomal P and lupus nephritis, more specifically with the histological features of membranous glomerulonephritis. 3 Anti-LPL antibodies were also described in systemic sclerosis, in fact, 35% of these patients can present such antibodies. In this disease, antibodies were also correlated to hypertriglyceridemia, but also to disease's activity measured by a longer extension of cutaneous fibrosis and a higher frequency of pulmonary fibrosis.…”

“…O anticorpo antidsDNA, presente em cerca de 40% dos casos, correlaciona-se com a atividade renal, e o anti-P ribossomal, presente em 10-20% dos pacientes, está associado a manifestações neuropsiquiátricas e renais. [1][2][3] Pela paucidade desses marcadores, a busca de novos anticorpos que se correlacionem com atividade do LES seria de grande auxílio para a clínica.…”

“…Antibody anti-dsDNA, present in 40% of the patients and related to renal involvement, and anti-ribosomal P protein antibodies, present in 10-20% of patients, associated with neuropsychiatryc and renal manifestations. [1][2][3] Due to the low frequency of such markers, searching for new antibodies that correlate with SLE activity should be helpful for clinical pratice.…”

Lack of association of antibodies to ribosomal P proteins with lupus membranous glomerulonephritis: Comment on the article by Do Nascimento et al

“…We read with interest the recent article by do Nascimento et al (1), in which they introduced antibodies to ribosomal P proteins as a novel marker for membranous lupus glomerulonephritis. Those investigators suggested that the presence of isolated anti-ribosomal P antibodies may discriminate patients with pure class V lupus nephritis, and that testing for these antibodies may be of clinical aid.…”

Anticorpo antiproteína P ribossomal em pacientes com hepatite autoimune

“…A maior frequência de cirrose no grupo anti-P positivo reforça o potencial papel patogênico desse anticorpo no fígado, assim como nas manifestações psiquiátricas no LES 29 , na nefrite lúpica 30,31 e na hepatite associada ao LES 12,16,32 . Estudos prévios demonstraram a presença da proteína ribossomal P0 em células de hepatoma 33 e a habilidade do anti-P penetrar nestas células e causar disfunção celular 14 .…”