To assess the prevalence of cryoglobulinemia in three groups of patients: HCV-positive/HIV-negative, HCV/HIV co-infected and HIV mono-infected.

From September 2002 to December 2003, 58 patients with documented HCV infection, 70 subjects with HIV/HCV co-infection, and 48 subjects with HIV infection alone were enrolled. Serum samples were tested for detectable cryoglobulins, liver enzymes, HCV viral load and HCV genotypes. Plasma HIV-RNA levels and CD4⁺ cell count were also evaluated in HIV-positive subjects.

Cryoglobulinemia was detected in 24.1% HCV mono-infected, 14.2% HCV/HIV co-infected and 6% HIV mono-infected patients. A significant statistical correlation was found between the presence of cryoglobulins and HCV infection (P=0.03), while cryoglobulins were unrelated to HIV mono-infection (P=0.16) and HCV/HIV co-infection (P=0.7). No significant correlation was observed between the presence of cryoglobulinemia and alanine transaminase (ALT) levels, HCV viremia and duration of HCV infection. Circulating cryoglobulins in HIV patients were not correlated with plasma HIV viral load, CD4⁺ cell count or duration of HIV infection. Only two HCV mono-infected patients complained of arthralgia.

A similar rate of cryoglobulinemia prevalence was detected in the patient groups with an HCV-related infection. HIV infection does not appear to play a significant role in cryoglobulin production.