Wells' syndrome: A pathogenic role for circulating CD4(+)CD7(-) T cells expressing interleukin-5 mRNA

Wells' syndrome, or eosinophilic cellulitis, is a rare dermatosis characterized histologically by a dermal infiltrate of eosinophils, lymphocytes and histiocytes between collagen bundles and amorphous or granular eosinophilic deposits on collagen, constituting name figures, We report a 54-year-old woman with eosinophilic cellulitis whose peripheral blood showed a marked eosinophilia and a high proportion of CD4(+)CD7(-) cells before treatment. Reverse transcriptase-polymerase chain reaction revealed that CD4(+)CD7(-) cells, but neither CD4(+)CD7(+) nor CD4(-)CD8(+) cells, in the circulating mononuclear cells expressed mRNA for interleukin (IL)-5, the major cytokine involved in eosinophilia. The proportion of CD4(+)CD7(-) cells decreased, and expression of mRNA for IL-5 disappeared in the peripheral blood, when the disease was treated by the administration of intravenous recombinant interferon-gamma. These findings suggest that circulating CD4(+)CD7(-) T cells play a pivotal role in the pathogenesis of eosinophilic cellulitis by producing IL-5.