The distribution of circulating CD4 lymphocyte subpopulations determined by reactivity with monoclonal antibodies anti-2H4 (CD45RA), anti-UCHL1 (CD45RO), anti-4B4 (CD29) and anti-Leu8, and analysed by dual colour immunofluorescence flow cytometry is described in a series of patients with B-CLL and in age-matched control subjects. The percentages and absolute numbers of CD4 cells reactive with anti-CD45RA, anti-CD45RO and anti-CD29 reagents were similar in the patient and control groups. In contrast, CD4+ Leu8+ cells (percentages and absolute numbers) were significantly reduced in B-CLL patients resulting in an inversion of the normal CD4+ Leu8+ :CD4+Leu8- ratio. The patients' clinical or therapeutic status did not appear to influence the levels of the respective CD4 subpopulations; nor was evidence of hypogammaglobulinaemia associated with specific numerical alterations in any of the CD4 subpopulations studied. It is proposed that, in B-CLL, the alterations in the CD4Leu8 subpopulations are associated with the disease process, whereas the distributions of CD4+CD45RA+, CD4+ CD45RO+ and CD4+ CD29+ cells reflect the normal physiological levels of these subpopulations in elderly subjects.
Keywords: B-Cell chronic lymphocytic leukaemia; CD4 cell subpopulations; flow cytometry; regulatory T lymphocytes.