Hepatitis C virus chronic infection as a common cause of mixed cryoglobulinaemia and autoimmune liver disease

Objectives. Mixed cryoglobulinaemia (MC) and autoimmune chronic hepatitis (AI-CH) are frequently associated with hepatitis C virus (HCV) chronic infection. Because HCV represents a possible common aetiological factor, the aim of the present study is to investigate the clinico-serological alterations of both MC and AI-CH and to verify a possible overlap between these disorders. Setting. Patients from three tertiary referral centres. Subjects. Two Italian series of 88 MC patients and 30 AI-CH type 1 were studied. Results. MC and AI-CH share several clinico-sero-logical features. The patients' mean age (MC vs. AI-CH: 60 ± 9 vs. 57 ± 13 years), disease duration (10.5 ± 5 vs. 9.6 ± 6 years), and female/male ratio (3.4 vs. 3.3) were very similar in the two series. Typical hallmarks of MC, i.e. purpura, arthralgias, and weakness, circulating mixed cryoglobulins with rheumatoid factor activity, and hypocomplement-emia were also recorded in a significant number of AI-CH patients. Similarly, chronic active hepatitis was found in 68% of MC patients and its histological and serological alterations were comparable with those of AI-CH; moreover, amongst various auto-antibodies, antinuclear antibodies and/or anti-smooth-muscle antibodies were detected in half of the cases of MC. Anti-HCV antibodies, detected by second-generation Chiron elisa and riba, were present in a high percentage of both MC and AI-CH (94 vs. 80%), and frequently associated with HCV viraemia (86 vs. 77%). Finally, anti-GOR, the HCV-related autoantibodies, were found in half cases of MC and AI-CH. Conclusions. On the whole, these data suggest that HCV in combination with other infectious and environmental and genetic factors can trigger a complex immunological disorder with different clinical patterns.