IGHA1 and meningitis: Given the high abundance of IgA in the gastrointestinal and respiratory tract mucosa, several IgA1 proteases from pathogenic bacteria associated with meningitis have been shown to generate Fab fragments from specific IgA antibodies produced in vivo, facilitating bacterial adherence to mucosal surfaces and promoting cellular invasion (Kilian et al, 2022; Weiser et al, 2003).