Mixed cryoglobulinemia associated with chronic HCV infection: problems of diagnosis and treatment

Mixed cryoglobulinemia is the most common extrahepatic manifestation of chronic HCV infection. Objective of the study . To investigate the frequency and diagnostic criteria of mixed cryoglobulinemia (MCG) associated with chronic HCV infection. Material and methods . The study included 83 patients with chronic HCV infection, aged 50.5 ± 12.6 years, of which 37 (44.6%) were men. The presence of cryoglobulins (CG) was examined, the cryocrit value was calculated, and rheumatoid factor (RF), complement component C4, and individual parameters of cellular immunity were determined. The frequency of MCG, its manifest forms, and immunological disorders were assessed, as well as the impact of antiviral therapy. Results . MCG was found in 61.4% of patients. Manifest forms of the disease were more frequently observed in the group of patients with a cryocrit of 1% or higher compared to those with a cryocrit of 0.5–0.99% (p < 0.017). In a multifactorial model, at a threshold cryocrit value of 0.5%, the detection of CG correlated with the duration of HCV infection (p = 0.001), and at a cryocrit value of 1%, it also correlated with a decrease in complement component C4 (p < 0.025). A sustained virological response (SVR) 12 weeks after the completion of therapy with direct-acting antiviral agents (DAAs) was achieved in 100% of patients. Despite the elimination of the virus, 29.4% of patients continued to have cryoglobulinemia. In 80% of patients with cryoglobulinemic vasculitis, immunological disorders persisted after the disappearance of CG. Conclusion . MCG develops in more than half of patients with chronic HCV infection and can be diagnosed with cryocrit values exceeding 0.5%. Early initiation of DAA therapy is a key factor in the prevention of MCG. The development of SVR does not exclude the persistence of MCG and immunological disorders in the early period after antiviral therapy, which necessitates mandatory long-term monitoring of these parameters.