Characteristic cytokine and chemokine profiles in encephalitis of infectious, immune-mediated, and unknown aetiology

Benedict D. Michael*, Michael J. Griffiths, Julia Granerod, David Brown, Nicholas W.S. Davies, Raymond Borrow, Tom Solomon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Background: Encephalitis is parenchymal brain inflammation due to infectious or immune-mediated processes. However, in 15-60% the cause remains unknown. This study aimed to determine if the cytokine/chemokine-mediated host response can distinguish infectious from immunemediated cases, and whether this may give a clue to aetiology in those of unknown cause. Methods: We measured 38 mediators in serum and cerebrospinal fluid (CSF) of patients from the Health Protection Agency Encephalitis Study. Of serum from 78 patients, 38 had infectious, 20 immune-mediated, and 20 unknown aetiology. Of CSF from 37 patients, 20 had infectious, nine immune-mediated and eight unknown aetiology. Results: Heat-map analysis of CSF mediator interactions was different for infectious and immunemediated cases, and that of the unknown aetiology group was similar to the infectious pattern. Higher myeloperoxidase (MPO) concentrations were found in infectious than immunemediated cases, in serum and CSF (p = 0.01 and p = 0.006). Serum MPO was also higher in unknown than immune-mediated cases (p = 0.03). Multivariate analysis selected serum MPO; classifying 31 (91%) as infectious (p = 0.008) and 17 (85%) as unknown (p = 0.009) as opposed to immune-mediated. CSF data also selected MPO classifying 11 (85%) as infectious as opposed to immune-mediated (p = 0.036). CSF neutrophils were detected in eight (62%) infective and one (14%) immune-mediated cases (p = 0.004); CSF MPO correlated with neutrophils (p<0.0001). Conclusions: Mediator profiles of infectious aetiology differed from immune-mediated encephalitis; and those of unknown cause were similar to infectious cases, raising the hypothesis of a possible undiagnosed infectious cause. Particularly, neutrophils and MPO merit further investigation.

Original languageEnglish
Article numbere0146288
JournalPLoS ONE
Volume11
Issue number1
DOIs
Publication statusPublished - Jan 2016

Bibliographical note

Funding Information:
BDM is an NIHR Academic Clinical Lecturer and this work received support as part of an NIHR Doctoral Research Fellowship (NIHR-DRF-2010-03-97). TS received support from the NIHR Health Protection Research Unit in Emerging and Zoonotic Infections at Liverpool. TS was also supported by the MRC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This work was supported by the laboratory team at the Vaccine Evaluation Unit, Public Health England, Manchester, UK. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health or Public Health England. The samples and data from these patients have been used in associated studies arising from the original Health Protection Agency (now Public Health England) Aetiological Study of Encephalitis in England.

Funding Information:
Funding: BDM is an NIHR Academic Clinical Lecturer and this work received support as part of an NIHR Doctoral Research Fellowship (NIHR-DRF-2010-03-97). TS received support from the NIHR Health Protection Research Unit in Emerging and Zoonotic Infections at Liverpool. TS was also supported by the MRC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This work was supported by the laboratory team at the Vaccine

Funding Information:
BDM is an NIHR Academic Clinical Lecturer and this work received support as part of an NIHR Doctoral Research Fellowship (NIHR-DRF- 2010-03-97). TS received support from the NIHR Health Protection Research Unit in Emerging and Zoonotic Infections at Liverpool. TS was also supported by the MRC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This work was supported by the laboratory team at the Vaccine Evaluation Unit, Public Health England, Manchester, UK. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, the Department of Health or Public Health England.

Publisher Copyright:
© 2016 Michael et al.

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