Elevation of matrix metalloproteinase-9 level in cerebrospinal fluid of tick-borne encephalitis patients is associated with IgG extravassation and disease severity.
BACKGROUND
Tick-borne encephalitis (TBE), caused by tick-borne encephalitis virus (TBEV), is an infectious disease involving the central nervous system (CNS). The pathogenesis of CNS injury has not been clearly demonstrated. Matrix metalloproteinase-9 (MMP-9) and some cytokines, such as interleukin 6 (IL-6), may play important roles in the disruption of the blood-brain barrier (BBB) and the pathogenesis of TBE.


METHODS
72 cerebrospinal fluid (CSF) samples were collected from TBE patients in north eastern China. IgG levels in CSF and serum were compared and MMP-9 and IL-6 levels were evaluated by ELISA. The correlation between the elevated MMP-9 levels and IgG extravasation, disease severity, and neuroinflammation was analyzed.


RESULTS
Increased concentration of MMP-9 was detected in some of the CSF samples, and the elevation was found to be closely related to CSF TBEV IgG extravasation and enhancement of IL-6 expression. Moreover, elevated levels of MMP-9 were found to be correlated with IL-6 enhancement. Four of the 72 patients, the ones who died, presented with high CSF MMP-9 levels.


CONCLUSIONS
In TBE patients, elevated CSF MMP-9 levels were associated with brain inflammatory reaction, disruption of the blood-brain barrier, and disease severity.
State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
Xiaoping
X
Kang
Yuchang
Y
Li
Jingjing
J
Wei
Yu
Y
Zhang
Cai
C
Bian
Kun
K
Wang
Xiaoyan
X
Wu
Yi
Y
Hu
Jing
J
Li
Yinhui
Y
Yang
D004675:Encephalitis, Tick-Borne / Q000276:immunology / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000134:cerebrospinal fluid*; D015850:Interleukin-6 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000134:cerebrospinal fluid*; D012720:Severity of Illness Index
C508600:IL6 protein, human; D007074:Immunoglobulin G; D015850:Interleukin-6; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9