The temporal dynamics of humoral immunity to Rickettsia typhi infection in murine typhus patients.
Clin Microbiol Infect
; 26(6): 781.e9-781.e16, 2020 Jun.
Article
in En
| MEDLINE
| ID: mdl-31678231
ABSTRACT
OBJECTIVES:
This study examined individuals with Rickettsia typhi infection in the Lao People's Democratic Republic (Lao PDR) to (a) investigate humoral immune dynamics; (b) determine the differences in reference diagnostic results and recommend appropriate cut-offs; (c) determine differences in immune response after different antibiotic treatments; and (d) determine appropriate diagnostic cut-off parameters for indirect immunofluorescence assay (IFA).METHODS:
Sequential serum samples from 90 non-pregnant, adults were collected at seven time-points (days 0, 7, 14, 28, 90, 180 and 365) as part of a clinical antibiotic treatment trial. Samples were tested using IFA to determine IgM and IgG antibody reciprocal end-point titres against R. typhi and PCR.RESULTS:
For all 90 individuals, reciprocal R. typhi IgM and IgG antibody titres ranged from <400 to ≥3200. The median half-life of R. typhi IgM was 126 days (interquartile range 36-204 days) and IgG was 177 days (interquartile range 134-355 days). Overall median patient titres for R. typhi IgM and IgG were significantly different (p < 0.0001) and at each temporal sample collection point (range p < 0.0001 to p 0.0411). Using Bayesian latent class model analysis, the optimal diagnostic cut-off reciprocal IFA titer on patient admission for IgM was 800 (78.6%, 95% CI 71.6%-85.2% sensitivity; 89.9%, 95% CI 62.5%-100% specificity), and for IFA IgG 1600 (77.3%; 95% CI 68.2%-87.6% sensitivity; 99%, 95% CI 95%-100% specificity).CONCLUSIONS:
This study suggests suitable diagnostic cut-offs for local diagnostic laboratories and other endemic settings and highlights antibody persistence following acute infection. Further studies are required to validate and define cut-offs in other geographically diverse locations.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Rickettsia typhi
/
Typhus, Endemic Flea-Borne
/
Immunity, Humoral
/
Antibodies, Bacterial
Type of study:
Clinical_trials
/
Diagnostic_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Adult
/
Humans
Country/Region as subject:
Asia
Language:
En
Journal:
Clin Microbiol Infect
Journal subject:
DOENCAS TRANSMISSIVEIS
/
MICROBIOLOGIA
Year:
2020
Document type:
Article
Affiliation country:
Tailandia