MAL and bacterial infectious disease: Indeed, Mal is the most polymorphic of the TLR signaling adaptors, and several studies have indicated that single nucleotide polymorphisms in the gene for Mal (TIRAP) are associated with increased susceptibility to bacterial infections, including those (e.g. Haemophilus influenzae) related to lung disease [53], [54] Accordingly, it is conceivable that increased apoptosis caused by Mal deficiency in the lungs may predispose to emphysematous changes upon exposure to an additional pathological insult, such as bacterial infection with lung pathogens, which is worthy of future investigation.