Cryoglobulinemia in Sjögren Syndrome: A Disease Subset that Links Higher Systemic Disease Activity, Autoimmunity, and Local B Cell Proliferation in Mucosa-associated Lymphoid Tissue

Objective: To compare systemic disease activity by validated tools, i.e., the European League Against Rheumatism Sjögren Syndrome Disease Activity Index (ESSDAI) and the Clinical ESSDAI (ClinESSDAI) scores, between primary Sjögren syndrome (pSS) with positive serum cryoglobulins and pSS without serum cryoglobulins. Methods: There were 825 consecutive patients with pSS who were retrospectively evaluated. Results: The ESSDAI and the ClinESSDAI scores were significantly higher in cryoglobulin-positive patients (p < 0.0001, for both scores). Cryoglobulinemia was significantly associated with these domains: constitutional (p = 0.003), lymphadenopathy (p = 0.007), glandular (p = 0.0002), cutaneous (p < 0.0001), peripheral nervous system (p < 0.0001), hematological (p = 0.004), and biological (p < 0.0001). Conclusion: Cryoglobulin-positive patients show the highest systemic activity in pSS.