These findings, together with increased LRG1 levels in serum in response to microbial or viral infections and other inflammatory stimuli, as well as the high binding affinity of LRG1 for cytochrome c (Cyt c) following its release upon apoptotic signals, have led to the proposal that LRG1 functions as an acute phase protein involved in the innate immune response (19, 20). This evidence concerns the gene LRG1 and viral infectious disease.