title: Antagonist-mediated down-regulation of Toll-like receptors increases the prevalence of human papillomavirus infection in systemic lupus erythematosus.
abstract: BACKGROUND
  Prevalence of an abnormal Papanicolaou smear was significantly increased in lupus patients in cross-sectional studies, associated with a higher prevalence of high-risk human papillomavirus (HPV) infection. The nucleic acid-specific Toll-like receptors (TLRs) locate at the endolysosomal compartments and trigger the induction of cytokines for the innate immune response. This study evaluated whether abnormal host innate immune response in lupus patients may enhance HPV persistence.
  
  
  METHODS
  Protein levels of TLRs 3, 7, 8 and 9 in cervical epithelial cells of lupus patients and controls with or without HPV infection were assessed using flow cytometry. Characteristics associated with the differential expression of TLRs in systemic lupus erythematosus (SLE) were elucidated. The effect and interferon-stimulated genes (ISGs) (ISG15 and Mx-1) gene expressions were then measured in oncogenic HeLa (HPV18), CaSki (HPV) and C33A (HPV negative) cell lines using flow cytometry and quantitative real-time PCR. Ex vivo productions of cytokines and interferon-gamma (IFN-γ) upon TLR ligands stimulations were subsequently measured using cytometric bead array and ELISA.
  
  
  RESULTS
  For subjects with HPV infection, levels of TLR3 and TLR7 were significantly lower in lupus patients compared with controls. Significantly decreased TLRs 7, 8 and 9 levels were observed in HPV-negative SLE compared to healthy controls. For SLE with and without HPV infection, TLR7 and 9 levels were significantly lower in infected SLE than those in HPV-negative patients. Independent explanatory variables associated with down-regulation of TLR7 level included HPV infection and a higher cumulative dose of prednisolone; while a higher cumulative dose of hydroxychloroquine and HPV infection were associated with down-regulation of TLR9 level. In cervical cell lines, TLRs 3, 7, 8, 9 protein levels and antiviral ISG15 and Mx-1 gene expressions were inhibited in two oncogenic HPV types. Functional data showed that the induction of pro-inflammatory cytokines by TLR ligands (R837, ssRNA and ODN2395) was greatly impaired in CaSki and HeLa than C33A cells.
  
  
  CONCLUSIONS
  In conclusion, prednisolone and TLR antagonist (hydroxychloroquine) may down-regulate protein levels of TLR7 and TLR9 in lupus patients, thereby decreasing the innate immune response against HPV infection. Upon infection, HPV further down-regulate TLR7 and 9 levels for viral persistence. Furthermore, reduction of nucleic acid-sensing TLRs 7, 8 and 9 in carcinogenic HPVs ensures that the expression of inducible pro-inflammatory cytokines is minimized to prevent the expression of antiviral ISGs (ISG15 and Mx-1) on a biologically relevant antiviral response.
authors.affiliation: Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, 30-32 Ngan Shing Street, Shatin, New Territories, Hong Kong, China.
authors.forename: Shui-Lian
authors.initials: SL
authors.lastname: Yu
authors.forename: Paul K S
authors.initials: PK
authors.lastname: Chan
authors.forename: Chun-Kwok
authors.initials: CK
authors.lastname: Wong
authors.forename: Cheuk-Chun
authors.initials: CC
authors.lastname: Szeto
authors.forename: Suzanne C
authors.initials: SC
authors.lastname: Ho
authors.forename: Karine
authors.initials: K
authors.lastname: So
authors.forename: May M Y
authors.initials: MM
authors.lastname: Yu
authors.forename: So-Fan
authors.initials: SF
authors.lastname: Yim
authors.forename: Tak-Hong
authors.initials: TH
authors.lastname: Cheung
authors.forename: Martin C S
authors.initials: MC
authors.lastname: Wong
authors.forename: Jo L K
authors.initials: JL
authors.lastname: Cheung
authors.forename: Apple C M
authors.initials: AC
authors.lastname: Yeung
authors.forename: Edmund K
authors.initials: EK
authors.lastname: Li
authors.forename: Lai-Shan
authors.initials: LS
authors.lastname: Tam
mesh_terms: D003430:Cross-Sectional Studies; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D005260:Female; D006367:HeLa Cells; D006801:Humans; D006886:Hydroxychloroquine / Q000494:pharmacology; D008180:Lupus Erythematosus, Systemic / Q000453:epidemiology* / Q000378:metabolism*; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000378:metabolism*; D015995:Prevalence; D011446:Prospective Studies; D051193:Toll-Like Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism* / Q000502:physiology
chemical_list: D051193:Toll-Like Receptors; D006886:Hydroxychloroquine