Cytokines and chemokines in dermatomyositis

Abstract

Dermatomyositis (DM) is a chronic immune disorder that primarily affects the muscle, skin, or even lungs and heart. The exact causes and workings of DM, as well as methods for monitoring disease activity in a patient and predicting how it will respond to treatment, are being researched. Irregularities in cells called cytokines and chemokines are commonly found in inflammatory disorders and are likely to play a role in DM. This study aimed to find out the association between blood levels of cytokines and chemokines, and the severity of symptoms, especially skin lesions (affected patches) and interstitial lung disease (ILD – a term used for a range of lung diseases), in people with DM or a subtype of the disease called clinically amyopathic dermatomyositis (CADM). They enrolled 40 DM/CADM patients, collecting blood samples, evaluating the scale of skin lesions and taking other information at their first visit to hospital. The researchers found that higher levels in the blood of the cytokine IFN-β and the chemokine CXCL-10 were linked to more severe symptoms (higher disease activity). Blood levels of the cytokines IL-6, IL-10, IL-18, IFN-β were significantly higher in the DM/CADM patients with a type of ILD called acute/subacute interstitial pneumonia (A/SIP) than the subset without. Higher blood levels of IL-6 and IL-18 were correlated with higher levels of an antibody called anti-MDA5 antibody (antibodies are produced by the immune system to fight off disease and infection). In conclusion, blood levels of IFN-β and CXCL-10 may be useful for assessing skin disease activity in DM/CADM. The cytokines IL-6, IL-10, IL-18 and IFN-β were highly correlated with the occurrence of A/SIP. In addition, IL-6 and IL-18 may play a role in the development of anti-MDA5 antibody associated ILD. These results may contribute to the better understanding of DM/CADM.