URINARY NEOPTERIN QUANTIFICATION INDICATES ALTERED CELL-MEDIATED-IMMUNITY IN HEALTHY-SUBJECTS UNDER PSYCHOLOGICAL STRESS

In an effort to quantify changes in cell-mediated immunity (CMI) in he althy subjects under stress, we measured levels of neopterin, a well-v alidated marker of CMI activation, in the urine of medical students un dergoing academic examinations. Neopterin/creatinine ratios measured o n the first day of examinations (mean 46 mumol/mol) were significantly lower than those measured two weeks before (mean 78 mumol/mol, p =.00 4). Minimum neopterin production coincided with maximum subjective str ess, as measured by a visual analogue scale. After examinations, neopt erin/creatinine ratios rose (means 62 mumol/mol immediately after, and 65 mumol/mol two weeks after examinations), and these levels were not statistically different from those two weeks before examinations. Ove r this post-examination period, subjective distress was significantly lower than at either time point before examinations. We conclude that urinary neopterin/creatinine ratios may change significantly during pe riods of psychological stress, indicating concomitant alterations in C MI activation.