However, there was a greater reduction in the number of CD19+CD27+ memory B cells in HLA-B*15 individuals than that in other individuals after BA.5.2 infection, this phenomenon might be responsible for the lower level of anti-prototype, anti-BA.5.2 and anti-XBB.1.16 Nab release after BA.5.2 infection. This evidence concerns the gene CD19 and infection.