The Role of CXC Chemokines in Pulmonary Fibrosis of Systemic Lupus Erythematosus Patients

Abstract

The inflammatory process in systemic lupus erythematosus (SLE) affects many organs including the lungs. CXC chemokines are suggested to play an important role in the pathogenesis of SLE and pulmonary fibrosis. To estimate the concentrations of CXCL9, CXCL10, CXCL11 in bronchoalveolar lavage fluid (BALF) of patients with and without pulmonary involvements of SLE to evaluate CXC chemokines role in the pathogenesis of pulmonary fibrosis in SLE. Twenty-six SLE patients and 31 healthy controls were evaluated using high-resolution computed tomography (HRCT), pulmonary function tests, the SLE Disease Activity Index (SLEDAI), assessing CXCL9, CXCL11, CXCL10 level in BALF (an enzyme-immunosorbent assay kit). The mean CXCL9 and CXCL11 concentrations in BALF were higher in SLE patients compared to healthy controls (34.09 ± 102.34 vs 10.98 ± 14.65 pg/mL, p < 0.001; 72.65 ± 112.89 vs 16.12 ± 83.75 pg/mL, p = 0.012, respectively). The disease activity scored by SLEDAI and the concentration of CXCL10 in BALF were significantly higher in the SLE patients with pulmonary fibrosis when compared with patients with normal HRCT (8.23 ± 3.19 vs 5.01 ± 2.41; 73.45 ± 34.12 vs 40.76 ± 41.65, respectively, in both p < 0.05). In SLE patients positive correlations were found between SLEDAI and the percentage of lymphocytes in BALF (r = 0.51, p < 0.05); CXCL9 and CXCL10 concentrations in BALF (r = 0.65, p < 0.001); CXCL9 and CXCL11 concentrations in BALF (r = 0.69, p < 0.001). In lupus patients with pulmonary manifestations positive correlations were found between CXCL11 concentration in BALF and SLEDAI (r = 0.55, p < 0.05), CXCL11 concentration and the percentage of neutrophils in BALF (r = 0.69, p < 0.05), CXCL10 concentration and the percentage of neutrophils in BALF (r = 0.57, p < 0.05). Our observations indicate that CXCL9 and CXCL11 play an important role in the pathogenesis of SLE but it needs further studies. These results suggest that CXCL10 and CXCL11 are associated with neutrophils accumulation in the alveolar space of SLE patients with pulmonary fibrosis and should be considered as potential factor of interstitial fibrosis.