The Role of Neutrophile-Lymphocyte and Platelet- Lymphocyte Ratios in the Differential Diagnosis of Idiopathic Pulmonary Fibrosis and Chronic Hypersensitivity Pneumonia

Aim Idiopathic pulmonary fibrosis (IPF) and chronic hypersensitivity pneumonitis (CHP) are interstitial lung diseases with overlapping clinical and radiological features, making differential diagnosis challenging. Inflammatory biomarkers such as neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been investigated in various diseases. This study aims to evaluate the role of NLR and PLR in distinguishing IPF from CHP. Materials and Methods This retrospective study included patients diagnosed with IPF and CHP based on multidisciplinary discussion between January 2013 and December 2018 at a tertiary chest diseases hospital. The neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios were calculated from blood samples obtained at the time of diagnosis. Demographic characteristics, laboratory parameters, and comorbidities were extracted from hospital records. Statistical analyses were performed to compare NLR and PLR values between the study groups and a healthy control group. Conclusion Our results indicate that NLR values were significantly higher in both IPF and CHP groups compared to the healthy control group. However, there was no statistically significant difference between IPF and CHP groups, suggesting that NLR and PLR are not reliable markers for differentiating these diseases. Further studies are needed to explore alternative biomarkers for the differential diagnosis of IPF and CHP. Keywords Idiopathic pulmonary fibrosis, chronic hypersensitivity pneumonitis, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, inflammatory biomarkers