Interleukin (IL)-20 And Interleukin (IL)-22 In Pleural Effusion

Objective The aim of the present study was to investigate the concentrations and clinical significance of interleukin(IL)-20 and interleukin (IL)-22 in pleural effusions(PE)with various etiologies.Methods Pleural effusion samples were obtained from 110 patients who presented to the respiratory institute(36 with malignant pleural effusion,34 with tuberculous pleural effusion,18 with bacterial pleural effusion,and 22 with transudative pleural effusion).The pleural effusion and serum levels of IL-20 and IL-22 were determined by sandwich enzyme-linked immunosorbent assays (ELISA).Results(1)There was no difference in neither pleural nor serum concentrations of IL-20 among all four groups(all p＞0.05);but the pleural IL-20 levels(35.9±6.0 pg/ml)were significantly higher than those in serum (27.6±6.2)(p＜0.05).The pleural concentrations of IL-22 in both tuberculosis (146.1(397.5)pg/ml)and bacterial(59.6(484.3)pg/ml)groups were significantly higher than those in malignant(14.5(6.9)pg/ml)and transudative(22.3±8.9 pg/ml)groups,and it is the lowest in malignant group(p＜0.05);but there was no statistical significance in serum concentrations of IL-22 among all four groups(p＞0.05);the pleural concentrations of IL-22 in both tuberculosis(146.1 (397.5)pg/ml)and bacterial(59.6(484.3)pg/ml)groups were significantly higher than those in responding serum(18.7(9.8)pg/ml,15.7(17.2)pg/ml)(p＜ 0.001).Besides,the IL-22 concentrations were significantly higher in benign PE (111.5(394.9)pg/ml)than those in malignant PE(14.5(6.9)pg/ml)(p＜0.001), while the difference of IL-22 concentrations did not reach statistical significance between benign serum and malignant serum(p＞0.05).(2)The pleural levels of IL-22 was positive correlated with the respongding serum levels(p＜0.05),but not correlated with pleural IL-20 levels(p＞0.05).Besides,there was no correlation between the concentrations of IL-20 in pleural effusion and serum(p＞0.05).(3)The cut-off value of pleural IL-22 for the diagnosis of infectious PE was 30.112 pg/ml with the corresponding sensitivity and specificity 0.829 and 0.872,respectively.Meanwhile,the cut-off value of pleural IL-22 for the differential diagnosis of benign and malignat PE was 19.721 pg/ml with the corresponding sensitivity and specificity 0.829 and 0.872,respectively.Conclusions Compared to non-infectious PE,IL-22 appeared to be increased in bacterial and tuberculosis PE.It indicated that IL-22 was likely to participate in the inflammatory response of pleurisy and the detection of pleural IL-22 could be a new tool to differential infectious and non-infectious PE. Besides,pleural IL-22 may also be helpful for the diagnosis of benign and malignant PE.