Functional diversity within the suppressor phenotype as defined by monoclonal antibody in T‐cell prolymphocytic leukemia

Abstract

A patient with T-cell prolymphocytic leukemia (T-PLL) is described. The malignant T-cells from the patient were predominantly Leu-2-positive, indicating a suppressor phenotype. The cells were then tested to determine their functional capabilities. The patient's Leu-2-positive cells initially suppressed B-cell proliferation, as predicted by their phenotype but later functioned as T helper cells in the pokeweed mitogen system without a change in phenotype. The cells also responded inadequately to alloantigen and mitogen despite addition of exogenous T-cell growth factor (TCGF). Leu-2-positive prolymphocytes from the spleen of the patient were constitutive producers of TCGF. Surface phenotype using monoclonal antibody was inadequate to predict T-cell function of the cells from this patient with T-PLL. In addition, these data suggest there may be functional subpopulations within the OKT8+ phenotype. Constitutive TCGF production by malignant post-thymic T-cells may represent a mechanism by which these cells sustain their own growth.

T-cell Prolymphocytic Leukemia

“…In the 1980s, several single case reports were described either as T-PLL or as other designations such as T-cell chronic lymphocytic leukemia (T-CLL). [2][3][4][5][6] The morphologic variation and cytogenetic characteristics in a series of patients with T-PLL were also documented, 7,8 and in the early 1990s, the clinical and laboratory features in 78 patients with T-PLL were reported. 9 T-PLL currently is recognized as a distinct T-cell malignancy that is included in the French-American-British (FAB) classification.…”

T-cell prolymphocytic leukemia with an unusual phenotype CD4+ CD8+

“…The concurrence of conspicuous red pulp involvement without white pulp infiltration has been described in other T-cell malignancies as well .54 In vitro studies showed that the T-PLL cells of our patient exhibited normal reactivity with PHA and Con-A and duely expressed HLA-DR and IL2 receptor after stimulation. In five of 11 cases tested, the neoplas- 19,22,27,29 cells of our case proliferated after stimulation with candida and tetanus toxoid. We cannot explain this remarkable finding.…”