Table 3.

Proposed criteria for the classification of mixed cryoglobulinemia (MC) patients.

Criteria	Serological	Pathological	Clinical
major	mixed cryoglobulins low C4	leukocytoclastic vasculitis	purpura
minor	rheumatoid factor + HCV + HBV +	clonal B-cell infiltrates (liver and/or bone marrow)	chronic hepatitis MPGN peripheral neuropathy skin ulcers
definite mixed cryoglobulinemia syndrome:
a) serum mixed cryoglobulins (± low C4) + purpura + leukocytoclastic vasculitis
b) serum mixed cryoglobulins (± low C4)+ 2 minor clinical symptoms + 2 minor serological/pathological findings
essential or secondary mixed cryoglobulinemia:
absence or presence of well-known disorders (infectious, immunological or neoplastic)

HCV+ or HBV+: markers of hepatitis C virus or hepatitis B virus infection (anti-HCV ± HCV RNA; HBV DNA or HBsAg); MPGN: membranoproliferative glomerulonephritis.