Elevated in vitro IL-4 production in a patient with elevated serum IgE.
BACKGROUND: We have cared for an unusual patient with serum IgE concentrations of up to 150,000 IU/mL who did not have the hyper-IgE syndrome. OBJECTIVE: Our objective in this study was to compare the regulation of in vitro IgE synthesis in this patient with results reported for in vitro IgE production by patients with the hyper-IgE syndrome. METHODS: We utilized an enzyme-linked immunosorbent assay to measure in vitro IgE production under varying conditions. In vitro cytokine production including IL-2, IL-4, IL-6, and interferon-gamma also was evaluated as was expression of the IgE receptor molecule CD23. RESULTS: B cells from this patient produced high concentrations of IgE. The patient was found to produce very high levels of interleukin-4 (IL-4) in vitro, to have high levels of soluble CD23 in his serum, and to have cells that were inconsistently responsive to the effect of IL-4 on IgE synthesis. CONCLUSIONS: Patients with elevated production of IL-4 may have increased serum IgE concentrations without having the hyper-IgE syndrome syndrome.