In contrast to normal B lymphocytes, CLL cells express CD5 antigen believed to be a T cell marker. We have assessed normal and malignant B cell compartments in CLL patients with the aid of two-colour immunofluorescence techniques (CDS-TRITC, DR-FITC). No clear correlation was found between progression of disease and parameters studied. However, there was a tendency for a diminution of normal B cells in advanced stages of disease.
KEY WORDS Chronic lymphatic leukemia B. lymphocytes Double immunofluorescence TNTRODUCTTON Recent data obtained with the use of two-colour immunofluorescence techniques have revealed the existence of two populations of B lymphocytes (LB) in the peripheral blood of patients with chronic lymphatic leukemia (CLL). The predominant population representing an expanded malignant LB clone is CD20+/CD5+, while the residual normal LB population is CD20+/CD5- (Murphy et al., 1987). However, the membrane expression of CD20 is usually quite weak (similarly to SmIg) (Terstappen et al., 1988; Vuiller et a/., 1988), and in some patients undetectable (Moller et al., 1987). While DP and DQ expression on CLL LB may also be abnormal, in the majority of cases DR is preserved (Fermand et al., 1985;Guy et al., 1986; Pluta et al., 1989). In the present work we have assessed normal and malignant LB populations in CLL using the DR/CDS techniques.
Methods
The CLL group comprised 20 patients (age 39-70 years, 18 males and two females). The diagnosis was established on the basis of peripheral lymphocytosis (> 5 x 109/1), histopathology of lymph nodes, cytological examination as well as surface membrane phenotyping of mononuclear cells isolated from peripheral blood. Staging according to Rai et al. (1975) and Binet et a1 (1981) and other data are shown in Table 1. Eight patients had not received any treatment prior to the testing. Ten patients were receiving cytostatic treatment (CVP, CHOP, CHLVP, MOPP), one was on chlorambucil, and one underwent plasmapheresis. Patients receiving treatment were off cytotoxic drugs for at least 3 weeks prior to the phenotyping. For indirect immunofluorescence, mononuclear cells (isolated from peripheral blood by standard Ficoll-Isopaque gradient centrifugation) were incubated at 4°C for 30 min with appropriately diluted anti-CD20) (BI) and anti-CD2 (9.6),