Vol 5, No 2 (2014)
Review paper
Published online: 2014-09-04

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Characteristics and prognostic significance of T regulatory lymphocytes in lymphoid malignancies

Magdalena Głowala-Kosińska, Sebastian Giebel
Hematologia 2014;5(2):145-153.

Abstract

Regulatory T lymphocytes (Treg) represent a small subpopulation of CD4+ cells responsible for inhibition of excessive immunologic response, contributing in this way to immune homeostasis. Treg cells are characterized by CD4+CD25highFOXP3+ immunophenotype. In many cases of solid tumors (e.g. colon cancer, lung cancer, ovarian cancer) the number of Treg cells is increased and its elevation is associated with unfavorable prognosis. Treg cells by their capacity to suppress other T lymphocytes present in tumor microenvironment impair immunologic response against tumor cells thus contributing to immune evasion by malignancies. The matter is more complicated in cases where the tumor originates from immune cells. Results from published studies evaluating Treg cells in B-cell malignancies are scarce and they show that the numbers of tissue or peripheral Treg cells can be either decreased or increased. Similarly, Treg number may be associated with either positive or negative prognosis. Thus, Treg function in lymphomas should not be considered by simple analogy to solid tumors. On the basis on in vitro studies it was postulated that Treg cells can control malignant B cells, preventing clonal proliferation of the latter. Therefore it is possiblethat Treg cells may play a new, so far poorly understood role in lymphoid malignancies. The aim of this paper is to review the original articles that analyzed Treg lymphocytes in lymphoid neoplasms and to discuss the controversies on associations of Tregs with prognosis in this setting.



Hematology in Clinical Practice