CHI3L1 and infectious otitis media: ELISA quantification showed a step-wise increase in CHI3L1 levels in both serum and stool of the untreated WT mice to WT mice that had undergone 1 cycle of DSS and to AOM/DSS treated WT mice, indicating that CHI3L1 levels are positively associated with the progression of colitis and CAC (Figure 3A, 3B).