[Decrease of the functional affinity of rheumatoid factors under the effect of tiopronin]. / Réduction de l'affinité fonctionnelle des facteurs rhumatoïdes sous l'effet de la tiopronine.

Sixteen rheumatoid arthritis patients were serologically examined, before and after a 2-month treatment with tiopronine (TP). The titer of agglutinating rheumatoid factor (RF) as well as the level of non-agglutinating RF were significantly reduced in serum and synovial fluid (SF). The functional affinity of the remaining RF was attenuated in serum (p less than 0.01) and SF (p less than 0.05). Conversely, the proportion of asialylated IgG was enhanced in serum (p less than 0.05) and SF (p less than 0.05). These findings would suggest that TP might restore the efficacity of sialyl transferase at the B lymphocyte level.