Plasma melatonin level detection with a high performance liquid chromatography (HPLC) method in tuberculosis patients

Tuberculosis continues to constitute an important health problem in recent years along with the increase in its spread. Though important improvements were gained in diagnosis and treatment, immuno-endocrine mechanism could not have been enlightened yet. Immunomodulator effect of melatonin is known for nearly 30 years, still, its possible effects on TB was not introduced. This study aims to expose the relationship between TB and melatonin, along with development of HPLC method for melatonin in human plasma.31 patients diagnosed for the first time for TB, and positive for both ARB and culture; and 31 healthy controls with no systemic disease were involved in the study. All participants were males, and mean ages were 22,9 ± 3,8 years in patients group and 23,6 ± 3,4 in control.For SPE method, a Waters Oasis HLB extraction column was used in a fluorescent detector equipped Agilent 1100 HPLC system with isocratic 75 mM sodium acetate/acetonitrile (72/28, v/v) (pH: 5) mobile phase setup. Melatonin displays excitation and emission spectra with wavelength maxima at 275 nm and 345 nm, repectively. 40 ? L injection volume was followed by 10 min run. Limit of detection (LOD), with external standard calibration method, was 0,25 pg/mL within a linearity up to 1000 pg/mL. Inter and intraassay coefficients of variation (CV) were 4,02% and 5,41%, respectively. Urine melatonin sulphate levels were analyzed with a commercial kit using ELISA method.Mean plasma melatonin levels (pg/mL) in patient group were detected as 33,17 (7,52-163,41), and 45,20 (19,27-288,99) in control (p=0,037). Mean urine melatonin sulphate levels ( ? g/24 h) were 6,5 (0,2-34,8) in patient groups, and 21,7 (3,9-99,8) in control (p<0,001).These results suggest a relation between TB and low level melatonin in serum. Anyway, further studies may elucidate melatonin?s mechanism for effect, protection against infection and its activity in treatment, laying new frontiers in treatment of TB.