Interleukin-6 analysis of 572 consecutive CSF samples from neurological disorders: A special focus on neuromyelitis optica.
|Crystal structure of IL-6 |
( protein data bank)
Clin Chim Acta. 2017 Mar 7. pii: S0009-8981(17)30080-3. doi: 10.1016/j.cca.2017.03.006. [Epub ahead of print]
AbstractBACKGROUND: Increases of cerebrospinal fluid (CSF) interleukin (IL)-6 has been reported in various neurological disorders but has never been systematically analyzed. We compared the CSF IL-6 concentrations among various neurological disorders and to evaluate the significance of CSF IL-6 measurements for the diagnosis of neuromyelitis optica (NMO).
METHODS: We retrospectively investigated the IL-6 concentrations of 572 consecutive CSF samples in patients with various neurological disorders. Additionally, the associations between clinical manifestations in NMO patients and CSF IL-6 concentrations were closely investigated.
RESULTS: Among the neurological disorders, patients with NMO had the highest CSF IL-6 concentration. Receiver operating characteristic analysis found the optimal cutoff CSF IL-6 value for diagnosing NMO as 7.8pg/ml, and the sensitivity and specificity were 0.7317 and 0.7694, respectively. In NMO, CSF IL-6 concentrations were correlated with the length of the spinal cord lesion and anti-aquaporin-4 antibody-positivity and decreased after treatment.
CONCLUSION: The practical application of CSF IL-6 measurements is useful in diagnosing neurological disorders, especially NMO.
IL-6 is an important inflammatory mediator, present in the inflammatory response to infections, as well as in autoimmune processes. At present, in the field of neurology, we are increasingly used and experienced in anti-IL-6 therapy (tocilizumab), especially in NMOsd (in cases of non-response in the control of inflammatory activity with Rituximab or an allergic reaction that prevents the continued use of anti-CD20 therapy).
This work from the Chiba University group (Japan) led by Dr. Akiyuki Uzawa is very interesting and valuable, given the number of patients assessed, the cutoff value to determine the sensitivity of the test for NMO, and help differentiation of other inflammatory pathologies of the CNS with the NMO (as well as differentiation between the acute presentation of events between NMO and MS)
As shown in the graph of the article,** in patients with NMO, the cutoff value of IL-6 in CSF was 7.8 pg / ml, with sensitivity of 0.7317 and specificity of 0.7694.
The conclusions of the analysis of IL-6 values in these different pathologies are:
• In patients with Multiple Sclerosis, there was no increase in IL-6 concentration in CSF (the diagnostic specificity between acute events between NMO-a and MS-a was 0.9252)
• IL-6 levels in CSF were related to spinal cord length lesion in NMO patients .
• Levels of IL-6 in CSF decrease after treatment in acute onset (corticoid / plasmapheresis)
• The measurement of IL-6 in CSF, could be an important biomarker in the differentiation between NMO and MS