Association of Anti-SS-A Antibodies with Lupus Nephritis in Patients with Glomerulonephritis

Anti-SS-A antibodies (anti-SS-A) are the most prevalent anti-extractable nuclear antibody (ENA). Glomerulonephritis (GN), characterized by intraglomerular inflammation and cellular proliferation, is the leading cause of end-stage renal failure. The association of anti-SS-A in various types of GN is not well established in the literature. The documented role of anti-SS-A in lupus nephritis (LN) is controversial; some studies did not mention any significant association, whereas others recognized them as potentially pathogenic. This study aimed to determine the association of anti-SS-A in patients suffering from various GN and its significance in LN patients.

This cross-sectional study evaluated 200 GN patients for the presence of anti-dsDNA and anti-ENA antibodies via indirect immunofluorescence (IFA) and Immunoblot assays, respectively. All patients had anti-cell antibodies in their sera, which were evaluated with the help of IFA using the HEp-2 cell line as substrate. Data was analyzed using SPSS software version 20. P-value ≤ 0.05 was considered statistically significant.

Anti-dsDNA were found in 56(28%) whereas anti-ENA in 94(47%) patients. Anti-SS-A was the most common anti-ENA, which was isolated in 58(29%) patients. In the anti-ENA positive group, single antigen specificity was present in 55 (58.5%) patients, whereas more than one antigen specificity was seen in 39 (41.5%) patients. Out of 58 patients with anti-SS-A antibodies majority presented with nephrotic syndrome 44 (76%), and most of them 51 (88%) had a clinical diagnosis of Lupus Nephritis (LN). Majority patients 31 (53%) also had another anti-ENA along with anti-SS-A (P = 0.05). 24 (41.4%) patients also had anti-dsDNA along with anti-SS-A. In the enrolled GN patients, anti-SS-A antibodies were found to be significantly associated with anti-SS-B and anti-Ribosomal P protein antibodies.

Although anti-SS-A are most prevailing anti-ENA, however their presence in GN patients needs special consideration to rule out an underlying autoimmune disorder. Previous studies have highlighted the pathogenic potential of anti-SS-A in GN patients. The results of this study are in agreement with these studies, as most of the GN patients with anti-SS-A were later on diagnosed as LN. These findings suggest that anti-SS-A may contribute to the disease pathogenesis. However, larger studies in various ethnic populations are needed to confirm these results for adequate patient management.

The study results predict pathogenic potential of anti-SS-A in GN patients. As the majority of patients were diagnosed as LN, GN patients with anti-SS-A antibodies need special consideration to rule out LN for adequate management