IL33 and cryohydrocytosis: As for serum IL-33 levels, we found that 60 patients with CHC had significantly higher IL-33 concentration than 65 healthy controls (362 ± 66 vs. 68 ±28 ng/ml, P < 0.001; mean difference -294, Confidence Interval (C.I.)95% 311.7-276.3) (Figure 1).