Zaimoku Y, Patel BA, Kajigaya S, et al. - Researchers undertook this inquiry among 104 untreated patients suffering from severe and very severe aplastic anaemia (AA), aged ≥ 18 years, to determine circulating B‐cell subpopulations, including CD24^hiCD38^hi regulatory B cells (Bregs), as well as total B cells, CD4⁺ T cells, CD8⁺ T cells and natural killer cells in this sample. Standard immunosuppressive therapy (IST) plus eltrombopag were used to treat all patients. Patients with AA vs healthy people were found to have markedly decreased CD24^hiCD38^hi Bregs, this was particularly true in very severe AA but residual Bregs continued to be functional, capable of generating interleukin 10; similar total B‐cell counts as well as the other B‐cell subpopulations were detected on comparing with healthy individuals. No correlation of CD24^hiCD38^hi Bregs with responses to IST was evident. Overall, a likely contribution of Breg deficits to the pathophysiology of immune AA was suggested by markedly decreased CD24^hiCD38^hi Bregs, specifically noted in very severe AA, with recovery following IST.