CD4 and neoplasm: Increased % of peripheral IL-10+ CD19+ CD24hiCD38hi Bregs in GC patients compared to healthy cohort, which correlated with tumour stage. TIL-Breg frequency was enriched compared to peripheral blood in GC. Bregs inhibited secretion of IFN-γ and TNF- α by CD4+ T cells, and induced CD4+ FoxP3+ Treg differentiation