Intrathecal production of neopterin and beta sub(2) microglobulin in tick-borne encephalitis (TBE) compared to meningoencephalitis of other etiology

To study the pathophysiology of tick-borne encephalitis (TBE), the kinetics of neopterin and beta sub(2) microglobulin ( beta sub(2)M) production were measured in sequential, cerebrospinal fluid (CSF) and serum samples in 133 patients with aseptic meningoencephalitis (TBE, n = 72; non-TBE, n = 61). Intrathecal production of neopterin was demonstrable in all patients. Neopterin levels in CSF were elevated already at day 2: geometric mean value in TBE 36 nmol/l (range 1-253), in the non-TBE group 29 nmol/l (0.2-96). At day 9 and week 6 the neopterin level was significantly higher in TBE (86 (19-725) and 17 (4-122) nmol/l) than in non-TBE (28 (5-109) and 3 (0.2-58) nmol/l) (p < 0.001). After 1 year CSF levels were within the normal range. The beta sub(2)M response in CSF followed the pattern of neopterin. The intensity and duration of neopterin and beta sub(2)M was not correlated to the clinical course. Neopterin seems to he a more sensitive indicator of intrathecal T-cell response and inflammatory reaction than beta sub(2)M. The results indicate that a long-lasting strong inflammatory reaction is of pathophysiological significance in TBE.