Immunophenotypic and idiotypic characterisation of the leukaemic B-cells from patients with prolymphocytic leukaemia: Evidence for a selective expression of immunoglobulin variable region (IGV) gene products

Abstract

B-cell prolymphocytic leukaemia (B-PLL) is a rare chronic lymphoproliferative disease characterised by a massive splenomegaly associated with a mild or no lymphadenopathy and a high leukocyte count, mostly representing prolymphocytic features. We have studied membrane expression of certain Ig V K and V II gene products in five patients with B-PLL using a panel of monoclonal anti-subgroup and anti-cross-reactive idiotype (CRI) antibodies. Membrane expression of leukocyte-associated markers has also been investigated. The leukaemic cells from four patients expressed V KIII and V KIIIb subgroup and sub-subgroup kappa light chains. The V KIIIb and V HI-associated CRI identified by the monoclonal antibodies (MoAb) 17–109 and G8 were co-expressed in one patient. No B-cells from the patients expressed the V HIII-associated CRI. The same pattern of CRI expression was observed in a serum paraprotein collected from one of the patients. These results suggest a biased selection for the IG V KIII and V KIIIb light chains in B-PLL.