Fc γ R IIB gene polymorphisms in Indian systemic lupus erythematosus (SLE) patients.

Background & objectives: Receptors for the Fc fragment of immunoglobulin G (Fc γ Rs) represent the link between humoral and cellular immune responses. Polymorphisms in Fc γ Rs have been identified as genetic factors influencing susceptibility to various autoimmune diseases. This study was aimed to identify Fc γ R IIB genotypes in Indian systemic lupus erythematosus (SLE) patients and to correlate these with clinical presentation and autoantibody profile. Methods: Eighty consecutive clinically diagnosed SLE patients were included. SLE patients were classified according to the American College of Rheumatology (ACR) criteria. Disease activity was assessed by Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). PCR-RFLP method was used to detect Fc γ R IIB polymorphism. Results: Of the 80 SLE patients, 53 were LN and 27 were SLE without nephritis. The mean SLEDAI score at evaluation was 6.5 ± 5.8. Among SLE patients Fc γ R IIB genotype frequency was 61.2 per cent for Ile/Thr, 20.0 per cent for Thr/Thr and 18.8 per cent for Ile/Ile as compared to 65, 12.5 and 22.5 per cent respectively among normal population. There was no significant difference for Fc γ R IIB genotypes between SLE and normals. The allele frequency for Thr allele in SLE patients was slightly higher (0.51) than in normals (0.45). Thr allele frequency in LN patients was slightly higher (0.53) than in SLE patients without nephritis (0.49). Though a higher percentages of symptoms like renal manifestations (81.3%), arthritis (62.5%) and oral ulcer (56.3%) were noted in patients with Thr/Thr genotypes, no significant difference was noted when these patients were compared with Ile/Ile and Ile/Thr genotypes. Interpretation & conclusions: The findings of this study indicate towards an involvement of Thr allele with SLE disease severity and clinical presentation in Indian SLE patients. Future study on a large sample is needed to support this finding to understand the association of Fc γ R IIB 232Thr/Thr genotype as a susceptibility factor in SLE.

Anti-nucleosome antibodies as a disease marker in systemic lupus erythematosus and its correlation with disease activity and other autoantibodies.

Background: Detection of anti-nucleosome antibodies (anti-nuc) in patients with systemic lupus erythematosus (SLE) has been well established and it is claimed that their presence is associated with disease activity. Aims: The aim of this study is to evaluate the incidence of anti-nuc antibodies and to correlate them with disease activity and its association with other autoantibodies like anti-nuclear antibodies (ANA), anti-double stranded DNA (anti-dsDNA), anti-histone antibodies (AHA), as well as autoantibodies to histone subfractions like H1, (H2A-H4) complex, H2B, and H3. Methods: This cross-sectional study included 100 SLE patients referred from the Rheumatology, Dermatology, and Nephrology Departments. SLE disease activity was evaluated by using SLE-Disease Activity Index (SLEDAI) score. A patient was defined as having active SLE when the SLEDAI score was more than 5.0. Fifty normal controls were also tested as a healthy control group. Anti-nuc antibodies, anti-dsDNA, and AHA were tested by Enzyme-Linked Immunosorbent Assay (ELISA) and ANA was detected by an indirect immunofluorescence test. Results: All patients studied were in an active stage of disease and were untreated, of which 44 patients had renal biopsy-proven kidney involvement, which was categorized as lupus nephritis (LN) and 56 patients did not show any renal manifestations (SLE without LN). Anti-nuc antibodies were positive in 88%, anti-dsDNA in 80%, and AHA in 38% of the cases. ANA was positive in all SLE patients studied. None of the normal controls was found to be positive for these antibodies. Although a slightly higher incidence of autoantibodies were noted in LN, there was no statistical difference noted between LN and SLE without LN groups for anti-nuc and anti-dsDNA antibodies (p > 0.05). A higher incidence of autoantibodies to ANA specificities were noted in anti-nuc positive cases, but there was no statistical difference between anti-nuc positive and anti-nuc negative cases for ANA specificities among LN and SLE without nephritis groups (p > 0.05). Conclusions: Anti-nuc antibody detection could be a better tool for the diagnosis of SLE. Although there was no significant difference in LN and SLE without LN groups, this study suggests that anti-nuc detection can be useful as an additional disease activity marker to other laboratory tests.