Immunological aspects of biopsy-proven lupus nephritis in Bahraini patients with systemic lupus erythematosus.

Lupus nephritis (LN) is a frequent and potentially serious complication of systemic lupus erythematosus (SLE) that may influence morbidity and mortality. Immunological investigations are aiding tools to the kidney biopsy findings in early diagnosis, in addition to monitoring the effect of therapy. The aim of the present study is to highlight the role of these investigations in a group of Bahraini patients and to determine whether there is any positive association between these findings and the outcome of LN. The current study is a retrospective case-control study of randomly selected 88 SLE patients, 44 with biopsy-proven LN and 44 without, acting as controls. All renal biopsies performed during the period from 1996 to 2012 were classified according to the World Health Organization classification. Immunological investigations analyzed are: Antinuclear antibodies (ANA), anti-ds DNA, anti-ENA, anti-cardiolipin antibodies (abs) and complement components C3, C4. Human leukocyte antigen (HLA) typing class II was performed on selected cases. All patients had positive ANA (100%). A significantly high frequency of anti-Smith abs among the non-LN group (43.18%) compared with the LN group (18.18%) was found (P <0.001). On the other hand, the anti-Ro/SSA abs in the non-LN group was also found at a statistically higher frequency (20.45%) compared with that in the LN group (4.54%) (P <0.01). Anti-ds-DNA abs were found to be higher in the LN group (84.09%) compared with the non-LN group (70.45%), but the difference was not statistically significant (P = 0.082). There was a positive association of ANA positivity and low C3 and or C4 in the studied group. In our study, 88.2% of the HLA typed patients had HLADR2, DR3 or both. In conclusion, in our Arabic Bahraini SLE patients, the presence of anti-Smith, anti-Ro/SSA and anti-RNP antibodies and the absence of anti-dsDNA antibodies are independent predictive markers for renal involvement. However, more prospective studies with a larger number of patients are essential to ascertain those findings.