Lyme meningoradiculitis: prospective evaluation of biological diagnosis methods

The symptoms of Lyme meningoradiculitis and the value of biological examinations in an endemic area were determined in a prospective study in which data were collected on all patients consecutively hospitalised for Lyme meningoradiculitis at our institution during an 18-month period. Specific antibody titres in the serum and cerebrospinal fluid (CSF) were determined by Vidas enzyme-linked-immunosorbent-assay (IgG + IgM), Dade-Behring enzyme immunoassay (EIA) (IgM; IgG) and Western blot analysis (IgG). We also searched for Borrelia burgdorferi in the CSF by PCR analysis and following culture on a specific medium. A control group was recruited, consisting of 16 consecutive patients who had been referred during the same period with suspected but not confirmed Lyme meningoradiculitis. Eleven patients were included. Borrelia EIA of the serum revealed that 40% of the patients had both elevated specific IgM titres and intrathecal synthesis of specific IgG; 40% of the patients was negative for IgM but had isolated intrathecal synthesis of IgG; 20% of the patients had elevated specific IgM titres without intrathecal synthesis of IgG. PCR analysis and the CSF culture were positive in one case only (B. garinii). The results of this study highlight the importance of systematic serological testing for B. burgdorferi in the CSF in the case of early neuroborreliosis suspicion, even in the absence of IgM serum antibodies, which was the case in 40% of the patients in the present study. Nevertheless, intrathecal anti-B. burgdorferi IgG synthesis, which remains the "gold standard" for the diagnosis of neuroborreliosis, was not detectable in 20% of the patients for whom diagnosis was subsequently confirmed by demonstration of specific serum IgM.