Serum anti-immunoglobulins in multiple myeloma and benign monoclonal gammopathy

Abstract

Sera from 111 patients with IgG myeloma (MM) and 76 patients with IgG benign monoclonal gammopathy (BMG) were examined for the presence of anti-IgG antibodies. Forty-nine and five-tenths percent of MM patients were positive as compared to 26.3% of patients with BMG and 28% of age-matched controls ( P < 0.005). Anti-IgG antibodies were most easily detected using Rh-positive cells coated with various human incomplete antibodies. Anti-IgG antibodies showed specificity for determinants present on whole IgG and, in some instances, Fc. No clear evidence for anti-idiotypic reactivity with autologous M components could be obtained. In most sera, anti-IgG factors appeared to be present in low-molecular-weight fractions (3.5–5.0S). The apparent increase in anti-Ig factors in MM as opposed to BMG may reflect a basic difference in control mechanisms.