Of further note, infants dying of sudden infant death syndrome (SIDS) were found to have overstimulated tonsillar germinal centers reflected by an increased number of IgG+ and IgA+ PCs (97), probably caused by airway infection; and such activated B cells were apparently distributed in excessive numbers to regional secretory effector sites, including the parotid glands (98), thereby giving rise to increased levels of salivary IgA and IgM in SIDS (99). The gene discussed is CD40LG; the disease is sudden infant death syndrome.