Frequencies of PB B cell subsets in healthy and HCV-infected cohorts. (a) Mann-Whitney U tests were employed to examine differences in percentages of total B cells of immature transitional (IT), naïve, marginal zone-like (MZ-like), tissue-like memory, IgG memory, and IgM memory B cells in 37 healthy and 38 HCV-infected donors. (b) Summary of mean percentages and standard deviations of B cell subsets. HCV+, HCV positive.