title: Cerebrospinal fluid of postherpetic neuralgia patients induced interleukin-6 release in human glial cell-line T98G.
abstract: Chronic intractable pain caused by postherpetic neuralgia (PHN) can be alleviated by intrathecal (i.t.) steroid therapy. We investigated the possibility that interleukin-6 (IL-6) release in an in vitro system could be a potential marker for evaluating the effectiveness of i.t. steroid therapy in PHN patients. We studied 32 patients who received a course of i.t. injection of water-soluble dexamethasone. Their therapeutic index was calculated as such: ((Pain score before treatment - Pain score after treatment)÷Pain score before treatment)×100%, and they were divided into two groups, therapy effective (index>50%) and ineffective (index<50%). Cerebrospinal fluid (CSF) from the patients was used to stimulate cultures of T98G glioblastoma cells, and the subsequent IL-6 release was measured by enzyme-linked immunosorbent assay (ELISA). Our results showed that the CSF triggered IL-6 release from T98G cells in a volume-dependent manner. IL-6 release was significantly lower when using CSF from the therapy effective patient group (p<0.001) compared to the therapy ineffective group. In particular, therapy effective patients had less IL-6 release even before treatment as compared to therapy ineffective patients. In the therapy effective group, in vitro steroid treatment suppressed the CSF's IL-6 releasing effect almost completely, whereas in the therapy ineffective group, the IL-6 release was significantly reduced but remained detectable. These in vitro tests may provide an objective evaluation on the efficacy of i.t. steroid therapy administered to PHN patients.
authors.affiliation: Department of Anaesthesia, Yong Loo Lin School of Medicine, National University of Singapore, 5 Lower Kent Ridge Road, Singapore 119074, Singapore.
authors.forename: Annabel S
authors.initials: AS
authors.lastname: Tay
authors.forename: Eugene H
authors.initials: EH
authors.lastname: Liu
authors.forename: Tat Leang
authors.initials: TL
authors.lastname: Lee
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Wataru
authors.initials: W
authors.lastname: Nishimura
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Minami
authors.forename: Yiong Huak
authors.initials: YH
authors.lastname: Chan
authors.forename: Chian-Ming
authors.initials: CM
authors.lastname: Low
authors.forename: Shinro
authors.initials: S
authors.lastname: Tachibana
mesh_terms: D002460:Cell Line; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D051474:Neuralgia, Postherpetic / Q000134:cerebrospinal fluid*; D009457:Neuroglia / Q000378:metabolism*
chemical_list: D015850:Interleukin-6
keywords: Interleukin-6; Neuroglia; Postherpetic neuralgia; Steroid