ANTI-SA COLD AGGLUTININ OF IGA CLASS REQUIRING PLASMA-EXCHANGE THERAPY AS EARLY MANIFESTATION OF MULTIPLE-MYELOMA

The case of a patient (Col) with multiple myeloma presenting as chroni c cold agglutinin (CA) syndrome is reported. The CA (Col) was a monocl onal IgA/k paraprotein which recognizes an antigen fully expressed in adult and newborn erythrocytes, sialidase sensitive and partially resi stant to proteases. Hemagglutination-inhibition studies showed that im munodominant N-acetylneuraminic acid bound alpha2 --> 3 to O-glycans o f glycophorins represents the CA(Col) epitope. These serological and b iochemical findings fit with the anti-Sa specificity, of which only tw o previous examples are known. The clinical manifestations of CA (Col) were characterized by marked acrocyanosis, generalized livedo reticul aris, and incapacitating dyspnea, but only mild hemolysis. Plasma-exch ange therapy was effective in quickly removing the CA and relieving th e associated clinical manifestations, but such benefit was only tempor ary. This is the first reported example of anti-Sa CA of IgA isotype a nd the first case of IgA CA syndrome treated by plasma exchange.