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Deficit of circulating CD19⁺ CD24^hi CD38^hi regulatory B cells in severe aplastic anaemia.

ABSTRACT: Immune aplastic anaemia (AA) is caused by cytotoxic T lymphocytes (CTLs) that destroy haematopoietic stem and progenitor cells. Enhanced type 1 T helper (Th1) responses and reduced regulatory T cells (Tregs) are involved in the immune pathophysiology. CD24^hi CD38^hi regulatory B cells (Bregs) suppress CTLs and Th1 responses, and induce Tregs via interleukin 10 (IL-10). We investigated circulating B-cell subpopulations, including CD24^hi CD38^hi Bregs, as well as total B cells, CD4⁺ T cells, CD8⁺ T cells and natural killer cells in 104 untreated patients with severe and very severe AA, aged ≥18 years. All patients were treated with standard immunosuppressive therapy (IST) plus eltrombopag. CD24^hi CD38^hi Bregs were markedly reduced in patients with AA compared to healthy individuals, especially in very severe AA, but residual Bregs remained functional, capable of producing IL-10; total B-cell counts and the other B-cell subpopulations were similar to those of healthy individuals. CD24^hi CD38^hi Bregs did not correlate with responses to IST, and they recovered to levels present in healthy individuals after therapy. Mature naïve B-cell counts were unexpectedly associated with IST response. Markedly reduced CD24^hi CD38^hi Bregs, especially in very severe AA, with recovery after IST suggest Breg deficits may contribute to the pathophysiology of immune AA.

SUBMITTER: Zaimoku Y

PROVIDER: S-EPMC7496711 | biostudies-literature |

REPOSITORIES: biostudies-literature

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