Eosinophilia associated with proliferation of CD(3+)4-(8-) alpha beta+ T cells with chromosome 16 anomalies.

We describe a patient with eosinophilia and an abnormal CD(3+)4-(8-) alpha beta+ T-cell population. Chromosomal analysis of sorted CD(3+)4-(8-) cells revealed abnormal karyotypes on chromosome 16. In the presence of IL-2 the production of IL-5 from CD(3+)4-(8-) cells was higher than that from CD(3+)4-(8-) cells. Eosinophil survival-enhancing activity in the patient serum was inhibited by a combination of anti-IL-5 and anti-GM-CSF monoclonal antibodies. These data suggest that increased production of IL-5 and GM-CSF from the abnormal CD(3+)4-(8-) cells might cause eosinophilia.