STUDIES ON THE ANTI-INFLAMMATORY ACTION OF 6-MERCAPTOPURINE

Abstract

The mechanism of action of 6-mercaptopurine (6-MP) on an egg albumin-induced inflammatory lesion in the skin has been studied in rabbits treated with 6-MP in a daily dosage of 18 mg/kg. Relative to control animals, significant decreases in the numbers of large lymphocytes and monocytes in the blood were observed in the 6-MP-treated animals by the 9th day of treatment, without significant decrease in the numbers of polymorphonuclear leukocytes and small and medium lymphocytes. Concurrently, a significant decrease was also seen in the percentage of tissue mononuclear cells in the inflammatory skin lesion. There was a highly significant correlation between the numbers of monocytes in the blood and the per cent of mononuclear cells in the lesion. A mean of 52% of the mononuclear cells in the tissue lesion phagocytosed carbon offering further evidence that the major cell involved was the blood monocyte.