title: Are false negative direct immnufluorescence assays caused by varicella zoster virus gE mutant strains?
abstract: Strains of Varicella zoster virus (VZV) have been described recently in which a single base mutation in the gE epitope abrogates binding of the 3B3 monoclonal antibody, which is widely used for virus detection in diagnostic laboratories. These strains, named VZV-MSP, are associated with a distinct phenotype in both in vitro culture and in SCID-hu mice. We investigated the possibility that negative direct immunofluorescence results, using the 3B3 antibody, where the presence of virus was confirmed by polymerase chain reaction (PCR) or tissue culture are due in some cases to the MSP strain of VZV. A total of 249 vesicle fluid specimens from people with suspected shingles were examined using direct immunofluorescence, tissue culture and a nested multiplex PCR for VZV, herpes simplex virus type 1 (HSV-1) and 2 (HSV-2). VZV was detected in 218 of 249 (87.6%) cases. Forty-five confirmed VZV specimens, but with negative (30) or indeterminate (15) immunofluorescence results, were analysed further. PCR was used to amplify a fragment in ORF 68 that encodes the VZV gE ectodmain recognised by 3B3 antibody. The fragments were sequenced and analysed for the single base change G448A (D150N), which is present in VZV-MSP as compared with the reference Dumas strain. No VZV gE mutant (MSP/MSP-like) was detected. Overall, PCR was found to be the most sensitive method of confirming VZV infection. False negative VZV immunofluorescence results are unlikely to be due to virus variants.
authors.affiliation: Skin Virus Laboratory, Centre for Cutaneous Research, St Bartholomew's and The Royal London School of Medicine and Dentistry, Queen Mary College, London, United Kingdom.
authors.forename: Yusri A
authors.initials: YA
authors.lastname: Taha
authors.forename: Mark
authors.initials: M
authors.lastname: Quinlivan
authors.forename: Fiona T
authors.initials: FT
authors.lastname: Scott
authors.forename: Mary
authors.initials: M
authors.lastname: Leedham-Green
authors.forename: Khidir
authors.initials: K
authors.lastname: Hawrami
authors.forename: Janice M
authors.initials: JM
authors.lastname: Thomas
authors.forename: Judith
authors.initials: J
authors.lastname: Breuer
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology; D005188:False Negative Reactions; D019085:Fluorescent Antibody Technique, Direct; D006562:Herpes Zoster / Q000175:diagnosis* / Q000821:virology; D014645:Herpesvirus 3, Human / Q000145:classification / Q000235:genetics / Q000276:immunology; D006801:Humans; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000276:immunology*; D014776:Virus Cultivation
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D014759:Viral Envelope Proteins; C056913:glycoprotein E, varicella-zoster virus