What to do and what not to do in serological diagnosis of pertussis: recommendations from EU reference laboratories

Abstract

Bordetella pertussis-specific antibodies can be detected by enzyme-linked immunosorbent assays (ELISAs) or multiplex immunoassays. Assays use purified or mixed antigens, and only pertussis toxin (PT) is specific for B. pertussis. The interpretation of results can be based on dual-sample or single-sample serology using one or two cut-offs. The EU Pertstrain group recommends that: (i) ELISAs and multiplex immunoassays should use purified non-detoxified PT as an antigen, that they should have a broad linear range and that they should express results quantitatively in International Units per millilitre (IU/ml); (ii) a single or dual diagnostic cut-off for single-serum serology using IgG-anti-PT between 50 and 120 IU/ml should be used, and diagnostic serology cannot be validly interpreted for one year after vaccination with acellular pertussis (aP) vaccines; (iii) IgA-anti-PT should only be used with indeterminate IgG-anti-PT levels or when a second sample cannot be obtained. This group discourages using: (i) other antigens in routine diagnostics, as they are not specific; (ii) micro-agglutination, due to its lack of sensitivity; (iii) immunoblots for pertussis serodiagnosis, as results cannot be quantified; (iv) other methods, such as complement fixation or indirect immunofluorescence, due to their low sensitivity and/or specificity.

High frequency of pertussis in older children and adolescents with prolonged cough in Turkey

“…After the fourth week of illness, the amount of bacterial DNA rapidly diminishes, which increases the risk of obtaining falsely-negative results. In vaccinated children, adolescents and adults with cough illness of ≤3 weeks' duration, PCR is the only appropriate method for diagnosis of pertussis 18,30,31 . A PCR method with high sensitivity such as IS481 is ideal for the evaluation of sporadic coughing illness in the age groups who are almost always either previously immunized against or exposed to B. pertussis 30 .…”

“…In vaccinated children, adolescents and adults with cough illness of ≤3 weeks' duration, PCR is the only appropriate method for diagnosis of pertussis 18,30,31 . A PCR method with high sensitivity such as IS481 is ideal for the evaluation of sporadic coughing illness in the age groups who are almost always either previously immunized against or exposed to B. pertussis 30 . In the present study, IS481 PCR assay was performed for diagnosis of pertussis in vaccinated children and adolescents with a cough of two to four weeks' duration.…”

Specifinių antikūnų prieš B. pertussis titrai gimdyvių ir virkštelių kraujyje

“…pertussis pasižymi gaminamų virulentiškumo faktorių gausa, kiekvienas jų turi savo vaidmenį kokliušo patogenezėje. Anti-PT IgG nustatymas ELISA metodu yra specifinis ir pats jautriausias serologinis testas diagnozuojant kokliušą, todėl naudojamas dažniausiai [11].…”

“…Jei antikūnų kiekis mėginyje siekė <20 EU/ml, asmuo buvo vertinamas kaip seronegatyvus [13,14]. Ūmi ar neseniai buvusi B. pertussis infekcija diagnozuota, jei antikūnų kiekis mėginy-je ->70 EU/ml [11,12].…”

Real-time PCR-based detection of Bordetella pertussis and Bordetella parapertussis in an Irish paediatric population

“…However, the use of serology for pertussis diagnosis in younger children is less useful due to recent vaccination, and the lack of pertussis toxin antibody response in up to 24 % of this age group (Stehr et al, 1998). Diagnostic serology cannot be validly interpreted for one year post-vaccination with acellular pertussis vaccines (Guiso et al, 2011).…”