Human anti IL-22R antibody significantly inhibited rIL-22 induced FLS proliferation in PsA. FLS were pretreated with anti IL-22R antibody (1000 ng/ml) for 1 hr then incubated with rIL-22 (100 ng/ml) at 37°C for 5 days. MTT assay was done to evaluate the inhibitory effect of anti IL-22R antibody (IL-22R Ab). Each experiment was done in triplicate. Results were expressed as Mean ± SEM of OD. Non parametric test, Friedman's ANOVA with Dunn's multiple comparison test was done to determine statistical significance.