Increased risks of lymphoma and death among patients with non-hepatitis C virus-related mixed cryoglobulinemia.

BACKGROUND

Data on essential mixed cryoglobulinemia (MC) are scarce, and most date back to studies before 1989 (ie, before the discovery of hepatitis C virus [HCV] infection). Our objective was to describe the spectrum of MC in the era of HCV infection.

METHODS

Retrospective study from a single university hospital's database of 1434 patients who tested positive for MC between January 1989 and December 2003.

RESULTS

One hundred thirty-three patients (9%) with persistent MC without HCV were included in the study. Sixty-five of 133 patients who fulfilled the criteria for MC vasculitis were compared with 118 patients with HCV-related MC vasculitis. The patients without HCV had increased frequencies of renal involvement and B-cell non-Hodgkin lymphoma (NHL), lower gammaglobulin levels, and higher death rates. Twenty-three of the patients had B-cell NHL (primarily of the lymphoplasmocytic and marginal zone types), and 8 patients had Sjögren syndrome. In multivariate analysis, a cryoglobulin level higher than 0.6 g/L (odds ratio [OR], 1.44) and the presence of MC vasculitis (OR, 4.3) and hypogammaglobulinemia (OR, 6.7) were independently associated with B-cell NHL. After a mean follow-up of 49.4 months, 18 (14%) of 133 patients had died, primarily of sepsis. In multivariate analysis, age at diagnosis older than 60 years (OR, 1.06) and renal involvement (OR, 5.20) were independently associated with death.

CONCLUSION

Patients with non-HCV-related MC vasculitis have a poor outcome and have a 4-fold increased risk of developing B-cell NHL.