What is the role of cytokines in the etiology of aplastic anemia?

Updated: Jan 29, 2021
  • Author: Sameer Bakhshi, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Answer

Suppression of hematopoiesis is likely mediated by an expanded population of CD8+ HLA-DR+, cytotoxic T lymphocytes (CTLs) that are frequently detectable in the blood and bone marrow of patients with aplastic anemia. These cells produce inhibitory cytokines, such as gamma-interferon and tumor necrosis factor, which can suppress progenitor cell growth. Polymorphisms in these cytokine genes that are associated with an increased immune response are more prevalent in patients with aplastic anemia. These cytokines suppress hematopoiesis by affecting the mitotic cycle and cell killing by inducing Fas-mediated apoptosis.

In addition, such cytokines induce nitric oxide synthase and nitric oxide production by marrow cells, which contributes to immune-mediated cytotoxicity and the elimination of hematopoietic cells. Hirano et al reported that CD8+ cytotoxic T cells raised against kinectin-derived peptides suppress colony-forming units (CFUs) in an HLA class I–restricted fashion, findings that suggest kinectin may be a candidate autoantigen in the pathophysiology of aplastic anemia. [24]


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