Prolymphocytic leukaemia.

A review of the main features of prolymphocytic leukaemia, based on 80 cases studied by the author since 1974, is presented. Prolymphocytes have a B-cell membrane phenotype with strong expression of surface Ig in 81% of cases (B-PLL) whilst the rest have T-cell markers (T-PLL). Both forms of the disease have distinct laboratory and clinical findings. T-PLL has a more aggressive course with a median survival of 7 months (24 months in B-PLL). Ultrastructural analysis demonstrates larger lysosomal granules in T-PLL cells which results in a higher content of acid hydrolases. The intriguing relationship of B-PLL with B-CLL is discussed in the light of new data with immunological markers.