Neutrophil-to-Lymphocyte Ratio Is Associated with Impaired Interferon-Gamma Release to Phytohemagglutinin.

• Main Authors: Kwang-Sook Woo, Byoung-Gwon Kim, Jae-Lim Choi, Bo-Ram Kim, Kyeong-Hee Kim
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2015-01-01
• Series: PLoS ONE
• Online Access: https://doi.org/10.1371/journal.pone.0125794

<h4>Objective</h4>The neutrophil-to-lymphocyte ratio (NLR) has been shown to predict adverse outcomes in several pathologic conditions. The majority of indeterminate interferon (IFN)-γ release assays were due to inadequate IFN-γ response to the phytohemagglutinin. We sought to study the value of NLR to predict an indeterminate result of QuantiFERON-TB Gold In-Tube (QFT-GIT) performed in routine laboratory practice.<h4>Methods</h4>Results from 2,773 QFT-GIT assays were analyzed. Data collection included demographic data, the level of IFN-γ to nil, mitogen, and TB antigen of QFT-GIT, total WBC, and a differential count. We calculated the absolute neutrophil count, lymphocyte count, and NLR.<h4>Results</h4>Of the total, 224 (8.1%) indeterminate results were observed. Twelve (1.8%) showed indeterminate results in the NLR range from 1.71 to 2.84, but 132 (19.2%) had indeterminate results in NLR ≥ 5.18 (p < 0.0001). The likelihood ratio for indeterminate results were 2.70 (95% CI, 2.36-3.08) in NLR ≥ 5.18 and 1.93 (95% CI, 1.64-2.27) in lymphocyte count ≤ 1050/μL. NLR and neutrophil count were independent predictors for indeterminate QFT-GIT result in multiple regression analysis. The IFN-γ response to PHA was negatively associated with NLR (r = -0.33, p < 0.001).<h4>Conclusion</h4>We showed that the NLR is an independent predictor of indeterminate QFT-GIT result. Low frequency of indeterminate results in group with normal NLR may imply the importance of a balance between two cellular compartments in physiological and pathological conditions.