Generation of suppressor cells in atopic patients during immunotherapy that modulate IgE synthesis

We prospectively studied the effect of ragweed immunotherapy on the generation of suppressor T cells that modulate total and antiragweed IgE production in five patients with seasonal allergic rhinitis. Suppressor T cell depletion was accomplished by treating mononuclear cells (MNCs) with the monoclonal antibody Leu 2b followed by the addition of complement. Treated and untreated MNCs were obtained before and during (6 to 24 months) immunotherapy and were cultured at 1 X 10(6) cells per milliliter for 7 days in RPM1-1640 containing 10% fetal calf serum. In order to determine the effect of ragweed antigen on IgE production, untreated or Leu 2b-depleted MNCs were incubated with short ragweed extract (SRW) (1.0 to 10 micrograms/ml) for 20 hours, washed three times, and incubated for a further 6 days. The cell-free supernatants from each were harvested and assayed for total IgE by use of a modified PRIST assay. To determine specific IgE, a modified RAST procedure was used. Total or antiragweed IgE production was calculated by subtracting preformed IgE from the total or specific IgE content in the supernatant. Depletion of Leu 2-positive cells did not affect total IgE production before immunotherapy. In contrast, a statistically significant increase was observed in total IgE 6 months (p less than 0.05) and 13 months (p = 0.005) after immunotherapy. Specific antiragweed IgE production at these times was also enhanced, but this increase did not reach statistical significance. Before immunotherapy was begun, preincubation of MNCs with SRW did not change the amount of total IgE produced.(ABSTRACT TRUNCATED AT 250 WORDS)