MS4A1 and isolated hemihyperplasia: IH with low CD8+/CD4+FOXP3+ ratio had significantly higher percentages of CD20+CXCR5− and CD20+CXCR5+ B cells (defined as the number of cells divided by the total count of 6 immune cell types in each IH) compared to IH with high CD8+/CD4+FOXP3+ ratio, regardless of their location (P < 0.05, Fig. 6A).