title: Concentrations of Immunoglobulin G Antibodies Against Pertussis Toxin Does Not Decrease Over a Long Period of Time in Japan.
abstract: Objective Adult patients with pertussis rarely show typical symptoms, such as paroxysmal coughing, inspiratory "whoop", or post-tussive vomiting. While a culture is regarded as the gold standard for diagnosis, the sensitivity is very low. Therefore, the diagnosis of pertussis in adults in clinical practice is mostly based on single-sample serology using an enzyme-linked immunosorbent assay (ELISA) with the pertussis toxin antigen. Various cut-off values for the anti-pertussis toxin IgG (PT-IgG) have been proposed. It has been reported that concentrations of PT-IgG fall below the defined cut-off about 4.5 months after infection on average, and within 1 year in most patients. We investigated the distribution and time course of the PT-IgG levels. Methods The data were collected from the medical records. Patients The study retrospectively identified subjects who had visited Ikebukuro Otani Clinic, which is a specialized clinic for patients with cough. We retrospectively reviewed 406 patients with PT-IgG measurements to investigate the age distribution of PT-IgG levels. The changes in PT-IgG levels over time were assessed in the 205 patients who had more than one PT-IgG measurement. Results PT-IgG levels were ≥100 EU/mL in more than 15% of subjects. The PT-IgG levels of a few subjects had diminished over a long period of time. Conclusion A PT-IgG level greater than the defined cut-off value simply indicates past infection or immunization in most subjects. As such, a single measurement of PT-IgG using the cut-off values might lead to overdiagnosis of pertussis. Further data collection and analysis are required.
authors.affiliation: Department of Respiratory Medicine, Tokyo Medical and Dental University, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Sakakibara
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ohtani
authors.forename: Torahiko
authors.initials: T
authors.lastname: Jinta
authors.forename: Toshihide
authors.initials: T
authors.lastname: Fujie
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Naohiko
authors.initials: N
authors.lastname: Inase
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Saito
authors.forename: Miho
authors.initials: M
authors.lastname: Akaza
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Sasano
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sumi
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial; D001886:Bordetella pertussis / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007564:Japan; D008297:Male; D037342:Pertussis Toxin / Q000276:immunology*; D013997:Time Factors; D014611:Vaccination; D014917:Whooping Cough / Q000175:diagnosis* / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007074:Immunoglobulin G; D037342:Pertussis Toxin