Evidence for a Gm ^ab Allele in the Gm System of American Negroes

Abstract

RHESUS-POSITIVE [Rh(+)] red blood cells coated with selected incomplete anti-D sera may be caused to agglutinate by serum from selected patients with rheumatoid arthritis¹. The agglutinating activity of the rheumatoid arthritis serum may be inhibited by sera from some normal individuals¹. Inhibiting normal sera are called Gm(+), non-inhibiting normal sera are called Gm(−). Four Gm factors detected by different pairs of rheumatoid arthritis and anti-D sera have been reported. They are Gm^{a 1}, Gm^{b 2}, Gm^{x 3}and Gm-like⁴.