Recent studies have suggested a diagnostic role of the B-lymphocyte attracting chemokine (CXCL13) in the cerebrospinal fluid (CSF) in Lyme neuroborreliosis (LNB). Our aim was to evaluate diagnostic accuracy of CSF CXCL13 in a cohort of 59 consecutive patients referred to hospital for suspected LNB. Thirty-seven patients were classified as definite LNB and used as the reference standard. Seven were classified as probable, and seven as possible LNB. Eight patients did not fulfil case definitions and were used as controls.
At presentation, CSF CXCL13 was elevated in all patients with definite LNB, as compared to a positive CSF B. burgdorferi (Bb) antibody index (AI) in 33 of 37. Pre-treatment sensitivity of elevated CSF CXCL13 and positive CSF Bb AI was 100 % (95 % CI = 91–100) and 78 % (95 % CI = 75–96) respectively (p = 0.053).
Among the eight control patients, CSF CXCL13 was normal in five and only slightly elevated in three, and Bb AI was negative in five. Specificity of CSF CXCL13 and Bb AI was similar 63 % (95 % CI = 31–86) (p = 1.0).
CSF CXCL13 was elevated in 6/7 patients with probable LNB and 3/7 patients with possible LNB. Bb AI was negative in all these 14 patients.
An additional control group consisted of 31 patients with multiple sclerosis (MS), 11 with non-inflammatory neurological diseases, and ten with verified non-Lyme meningitis and high CSF cell count. CSF CXCL13 was slightly elevated in 15 MS patients, and in nine meningitis patients. Mean CSF CXCL13 was higher in definite LNB (3524 ng/g CSF protein) than in MS (27 ng/g) and non-Lyme meningitis (23 ng/g) (p < 0.001).
Four months post-treatment CSF CXCL13 was normalized in 82 % of patients with definite LNB, as compared to a negative Bb AI in 10 % (p < 0.001).
CSF CXCL13 may be a useful supplement in early diagnosis of acute LNB.