We found that Bam32-/- mice have impaired germinal centre B cell response starting from day 28 post-infection, a time that correlated with onset of uncontrolled parasitemia, hepatomegaly, splenomegaly and lower serum levels of IgG, IgG1 and IgG2a in infected Bam32-/- mice. The gene discussed is DAPP1; the disease is parasitic infectious disease.