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Introduction. In recent years, cholesterol has received interest in the study of infection due to evidence of a relationship between low plasma cholesterol levels and tuberculosis (TB). Hypothesis/Gap Statement. Plasma lipid profiles of serum amyloid A (SAA), apolipoprotein A-I and high-density lipoprotein cholesterol (HDL-C) are biomarkers associated with symptomatic TB patients. Objective. We aimed to evaluate plasma lipid profiles of apolipoprotein A-I, SAA and the size of HDL as biomarkers to diagnose symptomatic TB patients. Methodology. Patients with TB symptoms attending the Instituto Brasileiro para a Investigação da Tuberculose/Fundação José Silveira (IBIT/FJS) between September 2015 and August 2016 for diagnosis of TB were studied. From 129 patients, 97 were classified as pulmonary TB and 32 as negative-bacilloscopy (non-TB group). Medical history, fasting serum and plasma were obtained. Total cholesterol (TC), HDL-C, apolipoprotein A-I and SAA were measured by enzymatic or immunochemical reaction assays. HDL size was measured by laser light-scattering. Results. In TB patients, TC (147.0±37 vs. 168±44 mg dL -1 ), HDL-C (37±14 vs. 55±18 mg dL -1 ) and apolipoprotein A-I (102±41 vs. 156±47 mg dL -1 ) concentrations were lower ( P <0.0001), while HDL particle size (10.16±1.02 vs. 9.62±0.67 nm) and SAA levels (280±36 vs. 19±8 mg L -1 ) were higher ( P <0.0001). Using receiver-operating characteristic curve analysis for predicting TB, the cutoff values were <83.85 mg L -1 for SAA (sensitivity=96.88 %, specificity=78.43 %, P <0.0001), >44.50 mg dL -1 for HDL-C (sensitivity=75 %, specificity=72.16 %, P <0.001) and >118.5 mg dL -1 for apolipoprotein A-I (sensitivity=83.83 %, specificity=72.22 %, P <0.001). Conclusion. SAA, HDL-C and apolipoprotein A-I are associated with TB infection and could be used as laboratory biomarkers, especially in patients who are negative for alcohol-acid-resistant bacilli.

It has been postulated that deficient or incomplete clinical and/or microbiological response to tuberculosis treatment is associated with cell-mediated immunological dysfunction involving monocytes and macrophages. A phase 2 safety trial was conducted by treating patients with either recombinant human granulocyte-macrophage colony-stimulating factor (rhu-GM-CSF) or a placebo, both in combination with anti-tuberculosis chemotherapy. Thirty-one patients with documented pulmonary tuberculosis were treated with rifampin/isoniazid for six months, plus pyrazinamide for the first two months. At the beginning of treatment, rhu-GM-CSF (125µg/M²) was randomly assigned to 16 patients and injected subcutaneously twice weekly for four weeks; the other 15 patients received a placebo. The patients were accompanied in the hospital for two weeks, then monthly on an out patient basis, for 12 months. Clinical outcomes were similar in both groups, with no difference in acid-fast bacilli (AFB) clearance in sputum at the end of the fourth week of treatment. Nevertheless, a trend to faster conversion to negative was observed in the rhu-GM-CSF group until the eighth week of treatment (p=0.07), after which all patients converted to AFB negative. Adverse events in the rhu-GM-CSF group were local skin inflammation and an increase in the leukocyte count after each injection, returning to normal 72 hours after rhu-GM-CSF injection. Three patients developed SGOP and SGPT > 2.5 times the normal values. All patients included in the GM-CSF group were culture negative at six months, except one who had primary TB resistance. None of the patients had to discontinue the treatment in either group. We conclude that rhu-GM-CSF adjuvant immunotherapy could be safely explored in a phase 3 trial with patients who have active tuberculosis.