Subsets of circulating blood IgA plasmablasts express CCR10 and CCR9. Peripheral blood lymphocytes were isolated, depleted of T cells, and stained for surface IgA (sIgA) or surface IgG (sIgG), CD19, a dump cocktail (CD14, CD3, IgD, and CD94), and CCR10, CCR9, or CCR6. (a) Of small memory lymphocytes expressing sIgA (CD19⁺sIgA⁺; 4% ± 2% of total CD19⁺ cells), few expressed CCR10 (3% ± 2%), while a small population expressed CCR9 (16% ± 5%), and virtually all expressed CCR6 (98% ± 1%). (b) Two discernable populations of dump cocktail–negative lymphocytes in the large lymphocyte gate could be identified by expression of sIgA and CD19. Large lymphocytes with an IgA memory phenotype (sIgA⁺CD19⁺) expressed CCR10 (4% ± 1%), CCR9 (28% ± 3%), and CCR6 (90% ± 2%) in a pattern similar to small sIgA⁺ memory lymphocytes. A large fraction of lymphocytes with an IgA plasmablast phenotype (sIgA^intCD19^int; roughly 0.1% of total CD19⁺ cells) expressed CCR10 (72% ± 8%), and a smaller fraction expressed CCR9 (17% ± 13%), while few expressed CCR6 (13% ± 3%). (c) The majority (>90%) of sIgA^-CD19^+/int lymphocytes (shown in b by box) are sIgG⁺. IgG⁺ memory lymphocytes (sIgG⁺CD19⁺) did not express CCR10 (3% ± 2%), while some expressed CCR9 (14% ± 3%), and almost all expressed CCR6 (84% ± 6%). Plasmablasts expressing sIgG (sIgG⁺CD19^int) contained some CCR10⁺ (13% ± 6%) and CCR9⁺ (16% ± 7%) lymphocytes and few CCR6⁺ (18% ± 4%) cells. Data are representative of four experiments from separate blood donors with data averaged across donors (mean ± SD).