Significance of anti-La/SSB antibodies in primary Sjögren's syndrome patients with combined positivity for anti-Ro/SSA and salivary gland biopsy

OBJECTIVES: Immunological parameters exert a relevant diagnostic and prognostic role in primary Sjögren's syndrome (pSS) and may identify specific disease phenotypes. Among disease-associated immunological features, anti-La/SSB are rarely found without concomitant anti-Ro/SSA and their clinical significance in patients with pSS has been poorly investigated. Thus, we aimed to characterise the value of anti-La/SSB analysing clinical and serologic features of a wide cohort of pSS patients with both circulating anti-Ro/SSA and positive salivary gland biopsy (SGB). METHODS: Clinical and serological data of 600 pSS patients with both anti-Ro/SSA and SGB positivity and categorised according to anti-La/SSB status were retrospectively analysed. Comparisons between patients with and without circulating anti-La/SSB were performed. RESULTS: Among the whole cohort, 319 (53%) of patients were anti-La/SSB negative and 281 (47%) were anti-La/SSB positive. Anti-La/SSB positive patients were younger at disease diagnosis and had a longer disease duration. Moreover, anti-La/SSB positive patients had a higher prevalence of hypergammaglobulinaemia and circulating rheumatoid factor and of lymphoproliferative disorders in comparison to seronegative group. At multivariate analysis, hypergammaglobulinaemia (OR=1,7; 95% CI 1.17, 2.43), rheumatoid factor (OR=2.3; 95% CI 1.6, 3.3) and lymphoma (OR=2.6; 95% CI 1.12, 5.96) were identified as independent variables significantly associated with anti-La/SSB positivity. CONCLUSIONS: In patients with pSS and concomitant anti-Ro/SSA and SGB positivity, the presence of anti-La/SSB may help in identifying a disease subset with distinct prognostic features, especially in terms of higher risk of lymphoproliferative complications