Comparison of microheterogeneity of alpha-1-acid-glycoprotein in serum and synovial fluid from rheumatoid arthritis patients.

Microheterogeneity of alpha-1-acid glycoprotein was studied using affinity immunoelectrophoresis with concanavalin A as a ligand in the samples of serum and synovial fluid obtained at the same time from 22 patients with rheumatoid arthritis. Individuals with intercurrent infection or other illnesses were excluded from the study. The results were expressed as reactivity coefficient (RC). Disease activity was evaluated by Mallya-Mace Activity Score, Lansbury Joint Index and laboratory tests. In most of the studied samples the glycosylation pattern was similar, composed of a nonreactive variant and 2 reactive (the first and the second) with Con A variants. In seven samples of synovial fluid an extra third peak representative of the strongly reactive one with Con A fraction was observed. It was the cause of the remarkable elevation of AGP-RC. Moreover, the level of IgM and IgA RF was higher in the synovial fluid derived from these patients--with the presence of the third peak in AFF-EP with Con A--than in those without the considered fraction.