IMMUNOPHENOTYPIC AND DNA GENOTYPIC ANALYSIS OF T-CELL AND NK-CELL SUBPOPULATIONS IN PATIENTS WITH B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA (B-CLL)

Absolute numbers and distributions of peripheral blood T-cells and NK cells were immunophenotypically determined in 21 patients with B-CLL and compared with those obtained from a series of 13 elderly normal controls with an age range of 60-87 years. For absolute CD3(+), CD4(+) and CD8(+) T-cell, and CD16(+) NK subpopulation numbers, there were no consistent differences between the normal and B-CLL groups although some individual patient variation was seen. Immunophenotypic analyses did however reveal that CD3(+) T-cells in almost half (10/21) of the B-CLL patients were Ia(+) (defined as >20% positive cells), compared to 0/13 of the elderly control group (p < 0.001), and that the proportions of CD4(+) and CD8(+) cells expressing membrane CD45RO were significantly increased compared to the control group. Subdivision of the B-CLL cases into those with low (<20%) and high (>20%) proportions of CD3(+) T-cells co-expressing Ia further showed that CD45RO expression by CD4(+) fractions was particularly prominent in the Ia(+) subgroup, and that the relative increase of CD4(+)CD45RO(+) cells was primarily a consequence of decreased absolute numbers of CD4(+)CD45RA(+) lymphocytes. This study also examined extracted DNA from enriched CD3(+) T-cell fractions (obtained by immunomagnetic bead selection in 9 of the B-CLL cases) by PCR analysis with two primers for the T-cell gamma gene locus. With the V gamma C (consensus) primer, 8/9 cases were polyclonal and the remaining case was oligoclonal. For comparison, 7/9 CD3(+) fractions were oligoclonal with the V gamma C primer with the other two cases being polyclonal. No monoclonal CD3(+) components were found. It is suggested that the observed increased Ia expression by CD3(+) cells and the predominance of CD4(+) cells expressing membrane CD45RO in patients with B-CLL may be of potential relevance to understanding the pathogenesis and patterns of disease progression.