Role of cell-mediated immunity in Hymenoptera allergy.

Currently there is little information regarding the immunologic mechanisms responsible for large local reaction (LLR) after Hymenoptera stings. To investigate this question, we measured in vitro lymphocyte proliferation and delayed skin reactivity to venom antigens in 10 subjects with LLR (six with LLR only and four with LLR and systemic reactions), seven subjects with systemic reactions, and eight nonallergic controls. The lymphocyte response to venoms in the LLR group was greater than that in either the systemic reactor group (p less than 0.05) or the control group (p less than 0.001). In contrast, lymphoproliferative responses to Candida albicans, streptokinase-streptodornase, and phytohemagglutinin were comparable in the three groups. Forty percent of the LLR group had positive delayed skin tests to venom antigens, and none of the patients in the systemic reactor group had such responses. These findings suggest that cellular immune mechanisms play a role in the pathogenesis of LLR after Hymenoptera stings.