Evaluation of plasma protein C and antithrombin levels in patients with tuberculosis

Background Tuberculosis (TB) is a global health problem and thromboembolic complications, when occurring, are often fatal, with no proven markers to predict. The most common type is latent tuberculosis infection (LTBI); however, patients can develop active TB disease and become infectious. Managing LTBI properly can prevent active disease evolution, and exclusion of active TB is the main primary question in LTBI management. Protein C (PC) and antithrombin (AT) are natural anticoagulants with anti-inflammatory properties, so they are suggested to have a role in hypercoagulability due to inflammatory processes. Aim To correlate PC and AT levels in TB patients with patients’ coagulable and clinical state. Patients and methods Sixty patients (20 pretreatment, 20 posttreatment active TB, and 20 LTBI) and 20 normal-controls were included. Activity levels of PC and AT were measured and correlated to patients’ coagulable and clinical states, and routine laboratory results. Results Activity levels of PC and AT are significantly low in active TB, increasing with treatment, and normal in LTBI. No thromboembolic events were detected in all patients included, so correlation with PC and AT could not be verified. Conclusion Active TB is associated with hypercoagulable state, with low activity levels of PC and AT. Both proteins are suggested to be used as adjuvant markers of activation of LTBI and during their pretreatment assessment, together with monitoring therapeutic response in patients with active TB.