Significance of concordant fluctuation and loss of leukocyte sensitivity to two allergens during injection therapy with one nonspecific desensitization

Abstract

Concordant, nearly parallel fluctuations in leukocyte sensitivity to 2 unrelated allergens were repeatedly observed during injection therapy with one of the allergens. In one case, complete loss of sensitivity or unresponsiveness to 2 unrelated allergens occurred during injection therapy with one. This nonspecific desensitization is considered to result from exposure of the sensitized leukocytes to concentrations of one of the allergens below the concentration required for detectable histamine release. This explanation is supported by data obtained by exposure of leukocytes in vitro to subthreshold concentrations of allergen, which resulted in decreased response in histamine release by the allergen used for desensitization and an unrelated allergen. In addition, intravenous infusion of allergen in low concentration into children likewise induced nonspecific desensitization of circulating leukocytes to 2 unrelated allergens. Concordant fluctuations and occasional nonspecific loss of leukocyte sensitivity to unrelated allergens during customary subcutaneous injection therapy may result from uneven or inadequate absorption of free allergen from the subcutaneous tissues into the circulation, thereby reaching desensitizing concentrations intermittently. This phenomenon calls for caution in assuming that the fluctuations of peripheral leukocyte sensitivity during injection therapy are necessarily a reflection of sensitivity of cells in the tissues.