Brief report: clonal proliferation of type 2 helper T cells in a man with the hypereosinophilic syndrome

An increase in the dose of methylprednisolone to 48 mg per day controlled this flare, but the symptoms recurred when the dose was tapered (Figure 1). Since interferon alfa therapy has been successful in the hypereosinophilic syndrome,14-16 a therapeutic trial of subcutaneous interferon alfa-2b (Schering-Plough, Innishannon, Ireland) was started at a dose of 5 million IU per day. Results Analysis of Rearrangements of the β Chain of the T-Cell-Receptor Gene Southern blot analysis of the DNA extracted from the patient's PBMC demonstrated the presence of a monoclonal-cell population in which the two alleles of the β chain of the T-cell-receptor gene were rearranged. The analysis of whole PBMC was repeated with three different restriction enzymes; all analyses demonstrated a clear pattern of clonal rearrangement, whereas no clonality was observed in a control patient with the hypereosinophilic syndrome who had a normal T-cell phenotype (data not shown). A pattern of cytokine secretion resembling that of type 2 helper T cells has recently been demonstrated in Sezary syndrome, a CD4+ lymphoproliferative disorder associated with hypereosinophilia and excessive serum levels of IgE25. Since serum levels of interleukin-5 dropped dramatically with steroid treatment, the initial response was probably mediated by the inhibition of interleukin-5 production by type 2 helper T cells as well as by a direct effect on the eosinophils26.