title: Differential expression of CD3 and CD7 in T-cell malignancies: a quantitative study by flow cytometry.
abstract: Most T-cell antigens are expressed on normal and neoplastic T lymphocytes and for this reason it is not easy to distinguish between the immunophenotype of normal and malignant T cells. We have addressed this problem by comparing the levels of expression of CD3 and CD7 on T lymphocytes from 18 healthy donors with those of 61 cases of T-cell leukaemia using quantitative flow cytometry with a method that converts fluorescence intensity into number of antigen molecules per cell. Normal T lymphocytes expressed 124 +/- 25 CD3 and 20 +/- 3 x 10(3) CD7 molecules per cell. The mean CD3 values were significantly lower in all types of T-cell leukaemia than in normal T cells (P < 0.05), with the exception of Sezary syndrome. The lowest CD3 values were found in T-lymphoblastic leukaemia (T-ALL), 30 +/- 21 x 10(3), and adult T-cell leukaemia/lymphoma (ATLL), 38 +/- 31 x 10(3), followed by T-prolymphocytic leukaemia (T-PLL), 92 +/- 47 x 10(3), and granular lymphocyte leukaemia (GLL), 95 +/- 21 x 10(3). In contrast, the number of CD7 molecules was significantly higher in T-All, 35 +/- 7 x 10(3) (P < 0.01), and T-PLL, 29 +/- 12 x 10(3), than the normal controls (P < 0.01), whereas ATLL and GLL showed a low CD7 expression, 13 +/- 3 and 12 +/- 3 x 10(3), respectively. Our results show that the quantitative analysis of CD3 and CD7 and their combined evaluation may enable a distinction between normal and leukaemic T cells and could facilitate the monitoring of minimal residual disease. This study has also defined the T prolymphocyte as a cell of intermediate maturity between thymic derived and peripheral T lymphocytes.
authors.affiliation: Academic Department of Haematology and Cytogenetics, Royal Marsden Hospital, London.
authors.forename: L
authors.initials: L
authors.lastname: Ginaldi
authors.forename: E
authors.initials: E
authors.lastname: Matutes
authors.forename: N
authors.initials: N
authors.lastname: Farahat
authors.forename: M
authors.initials: M
authors.lastname: De Martinis
authors.forename: R
authors.initials: R
authors.lastname: Morilla
authors.forename: D
authors.initials: D
authors.lastname: Catovsky
mesh_terms: D019011:Antigens, CD7 / Q000378:metabolism*; D017252:CD3 Complex / Q000378:metabolism*; D016516:CD4-CD8 Ratio; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D015458:Leukemia, T-Cell / Q000175:diagnosis*; D013601:T-Lymphocytes / Q000378:metabolism*
chemical_list: D019011:Antigens, CD7; D017252:CD3 Complex