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

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.