Seasonal variation of in vitro lymphocyte proliferative response to ragweed antigen E

Seasonal variation of symptoms and IgE response to short ragweed (SRW) allergens is well documented. Clinical symptoms generally parallel the rise and fall of the SRW-pollen count, whereas total and specific-IgE levels peak after the SRW-pollen season with a more gradual return to preseason levels. Because IgE synthesis is under T-lymphocyte control, we tested for seasonal variation in T cell-proliferative response to SRW antigen E (AgE) in vitro. Nine untreated SRW-sensitive and five nonallergic individuals were studied on 15 occasions from June 1981 through May 1982. In vitro proliferative index (SI) to AgE, serum total and specific IgE and SRW-pollen counts were measured; all persons studied kept daily symptom diaries. The mean SI was higher for the atopic group on all 15 sampling dates. The cumulative SI and the daily SI were statistically different between groups before, during, and after pollination. The peak SI for the atopic patients occurred almost 1 2/5 wk after the pollination peak, and the peak IgE antibody levels to SRW occurred at 5 2/5 wk after the pollination peak. We conclude that in vitro responsiveness to AgE is a specific response of allergic individuals and that this response demonstrates a significant seasonal component.