, Volume 90, Issue 4, pp 479-481,
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Date: 13 Jul 2010

T-cell prolymphocytic leukaemia: spontaneous immunophenotypical switch from CD4 to CD8 expression

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Dear Editor,

A 48-year-old man was incidentally found to have a lymphocytosis, with haemoglobin: 14.1 g/dL, white cell count: 16.6 × 109/L (77% abnormal lymphocytes), and platelet count: 160 × 109/L. The abnormal lymphocytes were small, with scanty basophilic cytoplasm showing frequent blebs (Fig. 1a). The nuclei contained condensed chromatin and inconspicuous nucleoli. They were predominantly positive for CD4 (Fig. 1b), and expressed CD2, CD5, CD7 and T cell receptor (TCR) αβ. Karyotyping showed inv(14)(q11q32) with multiple karyotypic aberrations (Fig. 1c). Serologic test for human T-lymphotropic virus 1 was negative. The diagnosis was consistent with T-prolymphocytic leukaemia (T-PLL) [1]. The patient elected not to receive treatment. Eight months afterwards, he presented with erythematous rashes, generalised lymphadenopathy and splenomegaly. A full blood count showed haemoglobin: 10.9 g/dL, white cell count: 132 × 109/L (95% abnormal lymphocytes), and platelet count: 139 × 109/L. In