Is minor salivary gland biopsy more than a diagnostic tool in primary Sjögren׳s syndrome? Association between clinical, histopathological, and molecular features: a retrospective study

Objectives: Several histological scoring systems, including the focus score, performed in minor salivary glands (MSGs) by hematoxylin-eosin (H&E) staining, have been employed in clinical practice to assess the inflammatory infiltrate and provide the diagnosis of primary Sjo¨gren׳s syndrome (pSS). Aims of this study were to integrate different scoring systems and identify potential differences in the molecular profile of lymphoid cytokines related to germinal center (GC) formation and clinical subsets in pSS.

Methods: Overall, 104 pSS patients and 40 subjects with sicca non-pSS were retrospectively evaluated. MSG biopsies were evaluated by H&E and immunofluorescence to assess histological pattern, Chisholm and Mason grading system, Tarpley score, a grading for the severity of inflammatory infiltrate, T-/B-cell segregation, and the presence of GC. MSGs from 50 pSS patients and 30 sicca non-pSS patients were processed by real-time PCR to assess LTα, LTβ, BAFF, CXCR4, CXCL12, CXCR5, CXCL13, CCR7, CCL19, and CCL21.

Results: GCs presence was associated with anti-Ro/SSA and anti-La/SSB antibodies, hypergammaglobulinemia, salivary gland swelling, higher Tarpley score and focus score, and extraglandular involvement but, at multivariate analysis, only extraglandular involvement was independently associated to GC. pSS patients displayed higher level of all cytokines compared to those with sicca symptoms. GC(+) pSS patients displayed higher level of all cytokines compared to those GC(-).

Conclusions: Our study demonstrates that different histopathological patterns, including GC presence, reflect different cytokine expression and different clinical subsets. We believe that the combined immunofluorescence/molecular approach in MSGs would help to tailor diagnostic and therapeutic approach for different subsets of pSS patients.