title: An investigation of antistreptococcal antibody responses in guttate psoriasis.
abstract: In two-thirds of patients with guttate psoriasis (GP), there is good evidence that the eruption is triggered by a streptococcal throat infection. We attempted to determine if a specific epitope of the bacterial pathogen was associated with the humoral immune response in GP patients. Antibody titres against beta-haemolytic streptococci (BHS) extracts in sera from 14 patients with GP, 10 healthy controls and 10 chronic plaque psoriasis (CPP) patients were determined by ELISA. Antibody BHS reactivity was investigated using immunoblotting, followed by epitope mapping using peptide-phage display. The highest GP antibody titres (10,000-25,000) were found in sera that had a matching streptococcal isolate, three sera had high (5,000-12,500) and seven had raised titres (500-5,000). In the healthy control group, three had relatively high and seven lower titres. All the CPP sera had very low titres (<500). In the immunoblots, three major bands were recognised by all the GP sera, and, to a lesser extent, by four healthy controls. No GP-specific protein was identified. Epitope mapping identified 10 phage clones that specifically bound 2 or 3 GP sera, displaying five different peptide sequences that were not streptococcal in origin. These findings suggest that the antigen specificity of the humoral response to BHS in GP does not differ from that of non-psoriatic individuals.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, The George S Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv, Israel.
authors.forename: Limor
authors.initials: L
authors.lastname: Nahary
authors.forename: Aviva
authors.initials: A
authors.lastname: Tamarkin
authors.forename: Nomy
authors.initials: N
authors.lastname: Kayam
authors.forename: Shlomo
authors.initials: S
authors.lastname: Sela
authors.forename: Lionel
authors.initials: L
authors.lastname: Fry
authors.forename: Barbara
authors.initials: B
authors.lastname: Baker
authors.forename: Anne
authors.initials: A
authors.lastname: Powles
authors.forename: Sarah
authors.initials: S
authors.lastname: Rogers
authors.forename: Itai
authors.initials: I
authors.lastname: Benhar
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial / Q000097:blood*; D001483:Base Sequence; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011565:Psoriasis / Q000276:immunology*; D013297:Streptococcus pyogenes / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial