Clinical studies on human tuberculosis, sepsis, viral infection, peritonitis, and pneumonia, whose incidence rise in the elderly [83], document that, after vitamin D supplementation, serum cathelicidin—human cathelicidin LL-37 or human cationic AMP 18 (hCAP-18)—increases, and correlates with improved clinical outcomes [84,85,86]. Here, CAMP is linked to susceptibility to pneumonia measurement.