IMMUNOPHENOTYPIC AND IDIOTYPIC CHARACTERIZATION OF THE LEUKEMIC B-CELLS FROM PATIENTS WITH PROLYMPHOCYTIC LEUKEMIA - EVIDENCE FOR A SELECTIVE EXPRESSION OF IMMUNOGLOBULIN VARIABLE REGION (IGV) GENE-PRODUCTS

B-cell prolymphocytic leukaemia (B-PLL) is a rare chronic lymphoprolif erative disease characterised by a massive splenomegaly associated wit h a mild or no lymphadenopathy and a high leukocyte count, mostly repr esenting prolymphocytic features. We have studied membrane expression of certain Ig V(K) and V(H) gene products in five patients with B-PLL using a panel of monoclonal anti-subgroup and anti-cross-reactive idio type (CRI) antibodies. Membrane expression of leukocyte-associated mar kers has also been investigated. The leukaemic cells from four patient s expressed V(K)III and V(K)IIIb subgroup and sub-subgroup kappa light chains. The V(K)IIIb and V(H)I-associated CRI identified by the monoc lonal antibodies (MoAb) 17-109 and G8 were co-expressed in one patient . No B-cells from the patients expressed the V(H)III-associated CRI. T he same pattern of CRI expression was observed in a serum paraprotein collected from one of the patients. These results suggest a biased sel ection for the IG V(K)III and V(K)IIIb light chains in B-PLL.