ABSTRACT
Purpose: The purpose of this study is to determine the tear and serum protein levels of interleukin-33 (IL-33) and its correlation with Th cytokines and disease severity in dry eye (DE) syndrome. Methods: Tear and serum samples were collected from 30 healthy volunteers, 30 DE patients with non-Sjogren's syndrome DE (NSSDE) and 30 DE patients with primary SSDE. The eight most frequent symptoms of DE were scored. All patients underwent corneal and conjunctival staining, tear film breakup time (TBUT), and Schirmer I test. The serum and tear levels of IL-33 were measured by enzyme-linked immunosorbent assay. The levels of IL-33 expression and its correlation with Th cytokines and disease severity were also analyzed. Results: We found that symptom scores and corneal staining grade were significantly higher in SSDE group compared with NSSDE and control group, whereas the results of TBUT and Schirmer I test were significantly lower in SSDE group compared with NSSDE and control group. The tear levels of IL-33 were significantly increased in tears of SSDE patients compared with those of controls and NSSDE patients (P < 0.05). Moreover, the elevated tear levels of IL-33 were positively correlated with symptom scores but negatively correlated with tear film breakup time and Schirmer I test in both NSSDE and SSDE patients (P < 0.05). The tear levels of IL-33 of both NSSDE and SSDE patients were also positively correlated with tear levels of IL-4 and IL-5 (P < 0.05). Correlation between the serum levels of IL-33 with Th1/17/Treg cytokines was not found. Conclusion: Elevated tear levels of IL-33 were associated with the Th2 cytokines and disease severity of DE. Therefore, IL-33 may have important roles in the immunopathogenesis of the DE.
ABSTRACT
Milk fat globule epidermal growth factor 8 (MFG-E8) is an opsonin involved in the phagocytosis of apoptotic cells. In patients with chronic obstructive pulmonary disease (COPD), apoptotic cell clearance is defective. However, whether aberrant MFG-E8 expression is involved in this defect is unknown. In this study, we examined the expression of MFG-E8 in COPD patients. MFG-E8, interleukin (IL)-1β and transforming growth factor (TGF)-β levels were measured in the plasma of 96 COPD patients (93 males, 3 females; age range: 62.12±10.39) and 87 age-matched healthy controls (85 males, 2 females; age range: 64.81±10.11 years) using an enzyme-linked immunosorbent assay. Compared with controls, COPD patients had a significantly lower plasma MFG-E8 levels (P<0.01) and significantly higher plasma TGF-β levels (P=0.002), whereas there was no difference in plasma IL-1β levels between the two groups. Moreover, plasma MFG-E8 levels decreased progressively between Global Initiative for Chronic Obstructive Lung Disease (GOLD) I and GOLD IV stage COPD. Multiple regression analysis showed that the forced expiratory volume in 1 s (FEV1 % predicted) and smoking habit were powerful predictors of MFG-E8 in COPD (P<0.01 and P=0.026, respectively). MFG-E8 was positively associated with the FEV1 % predicted and negatively associated with smoking habit. The area under the receiver operating characteristic curve was 0.874 (95% confidence interval: 0.798-0.95; P<0.01). Our findings demonstrated the utility of MFG-E8 as a marker of disease severity in COPD and that cigarette smoke impaired MFG-E8 expression in these patients.