This Christmas, learn how your body wages its own 'War on Christmas' against invading pathogens. In this immunological carol, we cover the immediate 'Home Alone' traps of the innate system (Neutrophils, NK cells) versus the elite 'snipers' and 'forgers' of the adaptive system (T-Cells, B-Cells). Master the fundamental differences and prepare for a complex clinical question on how clever viruses try to evade both.