Diagnostic accuracy of blood B-cell subset profiling and autoimmunity markers in Sjögren’s syndrome

Abstract

IntroductionThe aims of this study were to evaluate the diagnostic accuracy of blood B-cell subset profiling and immune-system activation marker assays in primary Sjögren’s syndrome (pSS) and to assess whether adding these tools to the current laboratory item would improve the American-European Consensus Group (AECG) criteria.MethodsIn a single-center cohort of patients with suspected pSS, we tested the diagnostic performance of anti-SSA, antinuclear antibody (ANA), rheumatoid factor (RF), gammaglobulins, IgG titers, and B-cell ratio defined as (Bm2 + Bm2′)/(eBm5 + Bm5), determined using flow cytometry. The reference standard was a clinical diagnosis of pSS established by a panel of experts.ResultsOf 181 patients included in the study, 77 had pSS. By logistic regression analysis, only ANA ≥1:640 (sensitivity, 70.4%; specificity 83.2%) and B-cell ratio ≥5 (sensitivity, 52.1%; specificity, 83.2%) showed independent associations with pSS of similar strength. In anti-SSA-negative patients, presence of either of these two criteria had 71.0% sensitivity but only 67.3% specificity for pSS; whereas combining both criteria had 96.2% specificity but only 12.9% sensitivity. Adding either of these two criteria to the AECG criteria set increased sensitivity from 83.1% to 90.9% but decreased specificity from 97.1% to 85.6%, whereas adding both criteria in combination did not substantially modify the diagnostic performance of the criteria set. The adjunction of RF + ANA ≥1:320, as proposed in the new American College of Rheumatology (ACR) criteria, did not improve the diagnostic value of anti-SSA.ConclusionsBlood B-cell subset profiling is a simple test that has good diagnostic properties for pSS. However, adding this test, with or without ANA positivity, does not improve current classification criteria.

Cytokine-induced STAT1 activation is increased in patients with primary Sjögren's syndrome

“…The immune cells from patients with pSS are activated in vivo, as demonstrated by increased expression of activation markers in T and B cells and secretion of autoantibodies by B cells [1,[23][24][25]. This activated phenotype might increase sensitivity to cytokine signaling.…”

Clinical features and potential relevant factors of renal involvement in primary Sjögren’s syndrome

“…Antinuclear antibodies positivity was defined in our cohort as a 1:320 titer or higher to exclude low titer ANA positivity as it’s not so specific especially in older people or those with other chronic diseases. Further, it is suggested that ANA 1:320 positivity and RF (especially IgA type of RF) are both related to the presence of anti‐SSA antibodies, and ANA 1:640 positivity and blood B‐cell subset profiling have good diagnostic properties for pSS . Therefore, high titer ANA positivity is much more significant in pSS.…”

What is the best salivary gland ultrasonography scoring methods for the diagnosis of primary or secondary Sjögren's syndromes?

“…Biologically, anti-SSA/SSB antibodies are the most specific markers, but are present in only 50% to 75% of pSS diagnostics. The anti-nuclear antibodies present in 80% of pSS and the rheumatoid factors in 40% to 75% of pSS, are non specific and can be found in other systemic autoimmune diseases [3][4][5]. The Sjögren's Syndrome is considered secondary (sSS) when associated with other connective tissue disease.…”