Objectives: To determine the prevalence and nature of cryoglobulins in a large series of patients with primary Sjögren's syndrome (SS) and identify the clinical and immunologic features related to their presence.
Methods: In a cross-sectional study, we investigated 115 consecutive patients (107 women and eight men) with primary SS. All patients fulfilled four or more of the preliminary diagnostic criteria for SS proposed by the European Community Study Group in 1993. Serum cryoglobulinemia was measured in all patients. Serum samples were obtained at 37 degrees C, and cryoglobulinemia was estimated by centrifugation after incubation at 4 degrees C for 7 days. The type of cryoglobulinemia was identified by agarose gel electrophoresis and immunofixation.
Results: Cryoglobulins were detected in the sera of 18 (16%) of our patients with primary SS; most were IgMkappa monoclonal/IgG polyclonal. When compared with patients without cryoglobulins, those with cryoglobulins presented a higher prevalence of leukocytoclastic cutaneous vasculitis (56% v8%, P < .001), hypocomplementemia (75% v 2%; P < 0.001) and antibodies to hepatitis C virus (HCV) (47% v8%, P < .001). Liver involvement (clinical signs, biochemical features, or ultrasound/histological data of liver disease) was present in all patients (100%) with cryoglobulins and HCV infection but in only 11% of patients with cryoglobulins without HCV infection (P < .001).
Conclusions: Leukocytoclastic cutaneous vasculitis, hypocomplementemia, and HCV infection are associated with the presence of cryoglobulins in the sera of patients with primary SS. Testing for HCV infection is recommended for patients with SS and cryoglobulinemia because of its high prevalence and its strong association with liver disease.