Eosinophilia associated with proliferation of CD3(+)4(-)8(-) alpha beta(+) T cells with chromosome 16 anomalies

We describe a patient with eosinophilia and an abnormal CD3(+)4(-)8(-)alpha beta(+) T-cell population. Chromosomal analysis of sorted CD3(+)4(-)8(-) cells revealed abnormal karyotypes on chromosome 16. In the presence of IL-2 the production of IL-5 from CD3(+)4(-)8(-) cells was higher than that from CD3(+)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 CD3(+)4(-)8(-) cells might cause eosinophilia.