Studies of the cellular infiltrate of chronic idiopathic urticaria: prominence of T-lymphocytes, monocytes, and mast cells.

We have used a panel of monoclonal antibodies and enzyme histochemistry in order to characterize further the perivascular mononuclear cell infiltrate found in chronic idiopathic urticaria. Biotinylated anti-mouse immunoglobulin was exposed to avidin-biotin-peroxidase-labeled complex followed by peroxidase development in order to detect binding of monoclonal antibodies. The mean percent staining obtained for 12 patients with chronic urticaria was 47% T-lymphocytes, 22% monocytes (14% by alpha-naphthyl acid esterase), and 11% mast cells. B-lymphocytes were not detectable, and approximately 20% of cells could not be identified. Although patients varied greatly in the ratio of Leu 3a positive helper-inducer T cells to T8 positive cytotoxic-suppressor cells, the average of all patients was not significantly different from the T4/T8 ratio in plasma. Our results suggest that the infiltrate resembles that observed in cellular immune reactions (although no antigen has been identified) and that interaction of T-lymphocytes and/or monocytes with mast cells to cause mediator release appears likely.