CD8 expression in a case of chronic lymphocytic leukemia with trisomy 12

We report a case of B-cell chronic lymphocytic leukemia (B-CLL) with aberra nt expression of the T-cell-associated antigen CD8, as revealed by two-colo r flow-cytometric analysis. DNA studies showed immunoglobulin heavy-chain g ene rearrangement, bur not of gamma-chain T-cell receptor, confirming the B -cell origin of the neoplastic cells. Ploidy analysis showed a tetraploid p opulation and high S-phase fraction. B-CLL cells also carried trisomy 12, d etected by fluorescence in situ hybridization. The identification of more c ases with the same features would be necessary to establish the prognosis o f this subtype of B-CLL. Copyright (C) 2000 S. Karger AG, Basel.