IDO in respiratory distress patients
Description
Data linked to the proposed publication: Diagnostic accuracy of Kynurenine to tryptophan ratio in peripheral blood to distinguish Tuberculosis from COVID-19, PCP or CAP. Tuberculosis (TB) kills almost as many people annually as COVID-19 killed in 2020, yet remains challenging to diagnose. The kynurenine (kyn)/tryptophan (trp) ratio, an indicator of indoleamine 2,3-dioxygenase activity, is of interest as a host biomarker of respiratory distress. We calculated the diagnostic potential of the kyn/trp ratio to distinguish TB from COVID-19, community-acquired pneumonia (CAP), Pneumocystis pneumonia (PCP) and non-communicable lung disease. We measured the kyn/trp ratio by ELISA on peripheral blood along with C-reactive protein (CRP) values as a comparator assay of the host immune response. An elevated kyn/trp ratio was seen in individuals with TB, COVID-19, CAP and PCP but not in those with non-communicable diseases. Individuals with TB had the highest kyn/trp ratio. At a cut-off value of 0.165, the kyn/trp ratio was able to differentiate individuals with TB disease from healthy control subjects with a sensitivity of 72.5%, specificity of 100.0%, positive predictive value (PPV) of 100.0% and negative predictive value (NPV) of 93.9%, and from patients with other aetiologies of respiratory distress with a sensitivity of 72.5%, specificity of 74.8%, PPV of 40.5% and NPV of 92.0%. The kyn/trp ratio performed better than CRP for distinguishing TB disease from other respiratory illnesses with the area under the receiver operating curve of 0.76 compared with 0.61. The kyn/trp ratio can be used as an adjunctive blood-based diagnostic test for TB.
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Steps to reproduce
Immusmol ELISA for Kynurenine and tryptophan levels conducted on serum from patients enrolled at hospitals for respiratory distress. Diagnoses were made with clinical investigations on erollment as well as laboratory tests required for each patient. Various statistical analyses were conducted on GraphPad Prism.