Macrophage-derived chemokine in malignant and tuberculous pleural effusions

Background and objectives: Macrophage-derived chemokine (MDC/CCL22) is recognized as a T-helper (Th) 2-type chemokine. Both malignant and tuberculous pleural effusions are typically lymphocytic pleural effusions. Tuberculous pleural effusions have a more polarized Th1 reaction than malignant effusions, which are predominantly Th2 in nature. The aim of this study was to compare the levels of MDC in malignant pleural effusions with those in tuberculous pleural effusions to help delineate the role of MDC in Th2 versus Th1 effusions. Methods: Forty-three patients with pleural effusions (32 malignant, 11 tuberculous) were studied. The concentration of MDC in the pleural effusion was measured by ELISA. Results: The median concentration of MDC was lower in malignant pleural effusions than in tuberculous pleural effusions (P < 0.005). Conclusions: MDC has been reported to both promote and suppress antitumour immunity. The low concentration of MDC in malignant effusions is likely to minimise its antitumour activity but the precise role of MDC in malignant and tuberculous effusions needs to be investigated further.