MICROHETEROGENEITY OF ALPHA(1)-ACID GLYCOPROTEIN IN EARLY AND ESTABLISHED RHEUMATOID-ARTHRITIS

Objective. To determine whether factors related to disease activity de termine changes in the glycosylation of alpha(1)-acid glycoprotein (AG P) observed at the early stage of rheumatoid arthritis (RA). Methods. Using affinoimmunoelectrophoresis with the lectin concanavalin A (Con- A), the microheterogeneity of serum AGP was studied in patients with e arly (n=54) and established (n=46) RA and the results were expressed a s reactivity coefficients (AGP-RC). Results. When compared with contro ls (n=44), AGP-RC values were increased in the patients with very rece nt RA of no more than 3 months duration (p<0.05), whereas normal or lo w AGP-Con-A reactivity was found in the patients with early RA with di sease duration exceeding 3 months. In the entire group with early RA, the multiplicative model of regression described the relationship betw een AGP-Con-A reactivity and disease duration (p<0.005). AGP variant w ith low binding affinity to Con-A predominated in the sera of patients with established RA and no relationship between the glycosylation pro file of AGP and disease duration was observed in this group. When AGP- RC values were compared in the subgroups of patients with early and es tablished RA with similar disease activity as measured by the Mallya-M ace score or erythrocyte sedimentation rate, there was a significant d ecrease in AGP-RC with increasing disease activity (p<0.05). Conclusio n. In view of our findings, early RA begins as an acute inflammation w ith increase of AGP-Con-A reactivity and becomes chronic during the fi rst year of the disease. Factors related to disease activity appear im portant in determining the rate at which RA enters a chronic phase.