Spontaneous B-cell IgE production in a patient with remarkable eosinophilia and hyper IgE

Background: The pathophysiology of eosinophilia and hyper-IgE is not fully elucidated yet. Objective: To clarify the pathophysiology of a patient with remarkable eosinophilia and hyper IgE, we examined cytokine levels in serum, surface antigens of peripheral blood eosinophils and IgE production in vitro. Results: Concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin3 (IL-3), interleukin-4 (IL-4), interleukin-5 (IL-5), and granulocyte/macrophage-colony stimulating factor (GM-CSF) in the serum were 21 pg/mL, <15 pg/mL, <15 pg/mL, 8 pg/mL, and <5 pg/mL pg/mL, respectively. Newly expressed surface antigens CD4, CD25, CD69, and HLA-DR, but not CD54, were observed on peripheral blood eosinophils. Extremely high levels of IgE secretion was found in the patient's mononuclear cells without stimuli; this was not enhanced by IL-4 or IL-4 plus anti-CD40 monoclonal antibody stimulation. Furthermore, highly purified B cells spontaneously produced large amounts of IgE and the production was not enhanced in addition of his T cells. Conclusion: The eosinophils were activated, and the B cells spontaneously produced IgE independently of T cells or cytokines, suggesting that intrinsic abnormality of B cells leading to disregulated production of IgE in this disease.