Impaired function subsequently leads to (1) a reduced number of IgM memory B cells and defective activity of opsonizing molecules, which facilitates infections by encapsulated bacteria, such as Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae, and (2) a decreased number of marginal zone B cells, which predisposes to the development of autoimmunity due to regulatory T cell depletion and subsequent increase in autoreactive T cell clones [64]. Here, CD40LG is linked to infection.