Clonal evolution of T-cell chronic lymphocytic leukaemia in a patient with ataxia telangiectasia.

Ataxia telangiectasia (A-T) is an autosomal recessive disorder in which patients show an unusual predisposition to malignant disease, including T-cell chronic lymphocytic leukaemia. We report here the steady growth over 5 years of a complex, cytogenetically abnormal clone of T lymphocytes in an A-T patient who was subsequently found to have an OKT3/OKT8 chronic lymphocytic leukaemia. The tumour cells at diagnosis had clearly evolved from a pre-existing, cytogenetically abnormal T-cell clone which contained an inv(14) chromosomal inversion alone.