Objective. The neutrophil-to-lymphocyte ratio (NLR) is elevated in inflammatory diseases, but its clinical significance in systemic sclerosis (SSc) is unclear. This study evaluated NLR in diagnosing SSc and in predicting lung involvement such as interstitial lung disease (ILD). Methods. The medical records of 88 patients with SSc and 50 healthy controls were reviewed. Exclusion criteria included active infection or the presence of any hematological, cardiovascular, or metabolic disorder. The NLR was compared between patients with SSc and healthy controls, and associations between NLR and lung involvement were analyzed. Results. The NLR was significantly higher in patients with SSc compared to healthy controls (NLR, 3.95±6.59 vs. 2.00±1.07, p＜0.01). Patients with SSc and ILD had higher NLR levels than those without ILD (p＜0.01, p＜0.05). NLR was negatively associated with forced vital capacity (r=−0.341, p＜0.01), but not with diffusing capacity for carbon monoxide. Receiver-operating characteristics analysis of NLR to predict ILD in patients with SSc showed that the area under the curve was 0.763. The cut-off NLR value for prediction of lung involvement was determined to be 2.59 (sensitivity, 0.700; specificity, 0.729; p＜0.01). Conclusion. NLR may be a promising marker that reflects ILD in patients with SSc, and values greater than 2.59 were useful in predicting ILD.

Keywords: Neutrophils, Lymphocytes, Blood platelets, Systemic sclerosis, Interstitial lung disease