Objective: To study the specificity of antibodies reactive with renal antigens in mixed cryoglobulinemia.
Methods: Sera from mixed cryoglobulinemia (MC) patients were tested on human kidney extracts by immunoblot. A partially purified renal antigen was subjected to N-terminal sequencing.
Results: Antibodies reactive with a renal antigen of 48 kD were detected in 7 out of 11 patients with MC and renal involvement. N-terminal sequencing of this antigen showed that it was identical with alpha-enolase. This result was confirmed by the reactivity of the renal antigen with a rabbit anti-serum specific for alpha-enolase.
Conclusions: The results indicate that antibodies specific for alpha-enolase are frequently produced by mixed cryoglobulinemia patients with renal involvement.