C4A and cryoglobulinemia: In HCV-associated MC, this profile (a) correlates inexactly with the level of cryoglobulin and titer of RF, (b) may occasionally be found in the absence of a detectable cryoglobulin, (c) may occur in the absence of RF in the serum supernatant after cryoprecipitation, (d) correlates only poorly with symptomatology in serial studies, and (e) may persist with cryoglobulinemia after apparent clearance of the virus [8–10]; these observations suggest a complexity of pathways to C4 depletion extending beyond IC activation and HCV infection.