Serum growth-regulated oncogene-alpha chemokine and its correlation with pulmonary fibrosis in systemic sclerosis

ABSTRACT

To determine serum levels of Growth-Regulated Onchogene-alpha [GRO-alpha] in systemic sclerosis [SSc] patients and correlate these levels with the presence and extent of pulmonary fibrosis detected by pulmonary function tests [% DLCO] and high resolution CT scan of lungs [HRCT]. The study included 23 SSc patients [8 limited and 15 diffuse] and 15 age and sex-matched healthy controls. All patients and controls were subjected to full history taking, thorough clinical examination, routine blood investigations, manometry, chest X-ray, spirometry to calculate the diffusing capacity of the lung for carbon monoxide [DLCO] and high resolution CT lung scan. Serum levels of GRO-alpha, anticentromere [ACA] and antitopoisomerase I [anti-top.I] antibodies were detected by enzyme linked immunosorbent assay [ELISA technique]. Serum levels of GRO-alpha were significantly higher in SSc patients [21.6 +/- 10.98 pg/ml] than in healthy controls [8 +/- 1.13 pg/ml] [p<0.001]. While there was no statistically significant difference between diffuse and limited SSc as regards GRO-alpha level [p>0.05], SSc patients with high serum GRO-alpha level had significantly increased frequency of decreased% DLCO [p<0.01] and the presence of anti-top I [p<0.01] compared to those with normal GRO-alpha level. In contrast, SSc patients with normal GRO-alpha level had increased frequency of ACA [p<0.001]. There was statistically significant association between elevated level of GRO-alpha and severity of lung function detected by decreased% DLCO [p<0.01] and high resolution lung CTscan [p<0.001]. Also, a highly significant negative correlation existed between serum GRO-alpha and decreased% DLCO [r= -0. 768, p<0.001]. Our results suggest that elevated serum level of GRO-alpha in SSc patients is correlated with pulmonary affection and may reflect the severity of lung fibrosis. Repeated and sequential analysis of GRO-alpha may clarify their usefulness as a serological marker for the severity of lung injury and enable us to better understand the pathogenesis of pulmonary fibrosis in SSc