Considering the lower half-life of IL-6 and its early role in the inflammatory cascade compared to CRP, lower levels of leukocytes, CCL18 and YKL-40 on admission sketches a picture of a burst-like inflammatory response in atypical CAPs compared with bacterial CAPs, somewhat similar to viral CAPs as mentioned earlier. This evidence concerns the gene CHI3L1 and cryopyrin-associated periodic syndrome.