IgE production by B-cells stimulated with interleukin-4 and Epstein-Barr virus in patients with elevated serum IgE levels.

Epstein-Barr virus (EBV) and recombinant interleukin-4 (rIL-4) induce IgE production by normal B-cells. We demonstrate here the difference in IgE synthesis in patients with elevated IgE levels and normal control subjects. EBV and rIL-4 induced the synthesis of IgE by surface IgE-negative B-cell precursors isolated by cell sorting. IgE synthesis in normal subjects became apparent in the second week with increasing rIL-4 concentrations, whereas in patients with elevated IgE levels, there was a marked elevation in IgE synthesis without rIL-4 stimulation. We did not observe the presence of DNA rearrangement occurring between IgM and IgE switch regions (S mu and S epsilon, respectively) during switching to IgE isotype in patients with elevated IgE levels. We found that with the limited sensitivity of Southern blotting, this method may not be useful for the study of B-cell populations in which only a small percentage of cells have undergone switching.