Lymphocyte sub-population counts after a single 40 mg administration of piroxicam in 20 patients with rheumatoid arthritis. A placebo-controlled study.

Abstract

Patients with active rheumatoid arthritis are characterized by a decrease in the number of circulating T-suppressor lymphocytes (identified by OKT8), resulting in an imbalance between helper (identified by OKT4) and suppressor cells. Piroxicam is a non-steroidal anti-inflammatory agent which modulates lymphocytic functions, especially by reducing the concentration of the rheumatoid factor in vitro and in vivo. A double-blind placebo-controlled study was performed in 20 patients suffering from active RA to investigate the acute effect of a single administration of piroxicam 40 mg on the number of circulating OKT3, T4, T8 and IA1 positive cells. Blood samples were obtained 16 hours before and 0, 2, 6, 8, 24, 48, and 72 h after administration of piroxicam or placebo. There was a significant decrease (P less than 0.05) in T4/T8 cell ratio 48 and 72 h after piroxicam, whereas placebo had no effect. There were no significant changes in absolute numbers of total T-lymphocyte (OKT3 positive cells), T-helper-inducer (OKT4 positive cells) and T-suppressor cytotoxic lymphocytes (OKT8 positive cells). The number of IA1 positive cells (B-cells and activated T-lymphocytes) was significantly higher in the afternoon samples (at 14.00 and 16.00 hours) than in the morning samples (at 08.00 and 10.00 hours) after both placebo and piroxicam administration (P less than 0.05). These data show that piroxicam decreases the T4/T8 cell ratio in active RA, but only 48 h after the first administration.(ABSTRACT TRUNCATED AT 250 WORDS)