CD19 and infection: Interestingly, the frequencies of CXCR5 expressing precursor (CD19+CD27+IgMhiCD21loCD1c+CD10+) and mature MZ-like (CD19+CD27+IgMhiCD21hiCD1c+CD10-) populations remained unaltered during the course of infection in all HIV-1-infected individuals (Fig 2E and 2F).