Analysis of Cytokine Levels in Meibum and Clinical Correlations with Meibomian Gland Dysfunction

Abstract

Objectives. This study is aimed at investigating the difference of meibum chemokines in MGD subjects with different degrees of MGD and the correlations of meibum chemokines with ocular surface parameters. Methods. Twenty MGD subjects (MQ $\text{score}>8$ ) and twenty MGD subjects (MQ $\text{score}\le 8$ ) were enrolled to examine ocular surface parameters, including meibomian gland function (MGE, MQ meibograde, and lid margin), tear stability (NIKBUT, FBUT, and LLT), tear secretion (SIT and TMH), OSDI questionnaire, and CFS. These subjects also obtained meibum samples, and then meibum chemokines (MIG, IFN-γ, IL-8, IP-10, and MCP-1) were examined and analyzed the correlations with ocular surface parameters. Results. MIG, IP-10, and MCP-1 were found clearly elevated in MGD subjects with higher MQ score than that in MGD subjects with low MQ score (MIG: $p=0.038$ , IP-10: $p=0.019$ , MCP-1: $p=0.040$ ). The meibomian function was found mostly positively correlated with level of MIG (MGE: $r=0.600$ , $p<0.001$ ; MQ: $r=0.579$ , $p<0.001$ ) and IP-10 (MGE: $r=0.719$ , $p<0.001$ ; MQ: $r=0.601$ , $p<0.001$ ). The tear stability was found negatively correlated with the level of MIG (NIKBUT: $r=-0.438$ , $p=0.005$ ; LLT: $r=-0.464$ , $p=0.003$ ) and MCP-1 (NIKBUT: $r=-0.425$ , $p=0.006$ ; LLT: $r=-0.761$ , $p<0.001$ ). The OSDI was positively correlated with IL-8, IFN-γ, and MIG. Conclusion. Chemokines in meibum were significantly evaluated in MGD subjects suffering from severe meibomian gland quality. These findings indicate that chemokines play roles in the pathogenesis of MGD, and molecules targeted by chemokines may develop as novel agents for MGD therapy, perhaps through inhibiting inflammation in meibomian glands and microvascular in the eyelid margin.