DETECTION OF ENTEROVIRAL RNA BY POLYMERASE CHAIN-REACTION IN CEREBROSPINAL-FLUID FROM PATIENTS WITH ASEPTIC-MENINGITIS

An assay based on a 2-step (semi-nested) polymerase chain reaction (PC R) was developed and evaluated for detection of enterovirus-specific R NA in cerebrospinal fluid (CSF) from patients with aseptic meningitis of different etiology. The limit of detectability of enteroviral RNA w as equivalent to about 0.25 tissue culture infective doses 50%. In sam ples, stored at -70 degrees C, analyzed without repeated thawing, ente roviral RNA was demonstrable in 21/22 CSF specimens from which an ente rovirus had been isolated. Enteroviral RNA was shown to be degraded du ring freeze-thawing of the samples. In repeatedly freeze-thawed sample s from 134 consecutive patients with aseptic meningitis, a lower sensi tivity (34/48 = 0.71) was observed. In the latest phase of the study, comprising 35 consecutive patients, the PCR was performed in CSF store d at -20 degrees C without thawing. In this material, the PCR yielded positive results in 19 patients, whereas enteroviruses were isolated f rom 6 cases only. In the total clinical material of 169 patients, 67 ( 40%) were found positive by PCR, whereas an enterovirus was isolated f rom CSF in 54 (32%) cases. Ail the 13 isolated enterovirus serotypes f ound in the study were demonstrable by PCR, indicating that the assay is broad-reacting within the enterovirus group. The specificity appear ed to be high, since all of 21 patients with non-enteroviral diagnoses were negative by the PCR test, except 1 with an Epstein-Barr virus in fection. As serological evidence of enteroviral etiology was found in this patient, a dual infection seemed probable. This study indicates t hat enteroviral RNA can be detected in CSF by a 2-step PCR in meningit is caused by enterovirus and that the technique has the potential to b ecome a screening method for routine diagnosis of enteroviral meningit is.