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Cross-sectional study of population-specific streptococcal antibody titres in Uganda
  1. Emmy Okello1,
  2. Meghna Murali2,
  3. Joselyn Rwebembera1,
  4. Jenifer Atala1,
  5. Asha C Bowen3,4,
  6. Nada Harik2,
  7. Gloria Kaudha1,
  8. Samalie Kitooleko1,
  9. Chris Longenecker5,6,
  10. Emma Ndagire1,
  11. Isaac Otim Omara1,
  12. Linda Mary Oyella1,
  13. Tom Parks7,
  14. Jafesi Pulle1,
  15. Craig Sable2,
  16. Rachel Sarnacki2,
  17. Elizabeth Stein8,
  18. Meghan Zimmerman9,
  19. Nicholas de Klerk3,
  20. Jonathan Carapetis3,
  21. Andrea Beaton10,11
  1. 1 Uganda Heart Institute Ltd, Kampala, Uganda
  2. 2 Children's National Health System, Washington, District of Columbia, USA
  3. 3 Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia
  4. 4 University of Western Australia, Crawley, Western Australia, Australia
  5. 5 Case Western Reserve University School of Medicine, Cleveland, Ohio, United States
  6. 6 University Hospitals Cleveland Medical Center, Cleveland, Ohio, United States
  7. 7 London School of Hygiene and Tropical Medicine, London, UK
  8. 8 University of Washington School of Medicine, Seattle, Washington, United States
  9. 9 Dartmouth-Hitchcock School of Medicine, Dartmouth, New Hampshire, United States
  10. 10 Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
  11. 11 University of Cincinnati School of Medicine, Cincinnati, Ohio, United States
  1. Correspondence to Dr Andrea Beaton, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; andrea.beaton{at}cchmc.org

Abstract

Objective Despite substantial variation of streptococcal antibody titres among global populations, there is no data on normal values in sub-Saharan Africa. The objective of this study was to establish normal values for antistreptolysin O (ASO) and antideoxyribonuclease B (ADB) antibodies in Uganda.

Design This was an observational cross-sectional study.

Setting This study was conducted at Mulago National Referral Hospital, which is located in the capital city, Kampala, and includes the Uganda Heart Institute.

Patients Participants (aged 0–50 years) were recruited. Of 428 participants, 22 were excluded from analysis, and 183 (44.4%) of the remaining were children aged 5–15 years.

Main outcome measures ASO was measured in-country by nephelometric technique. ADB samples were sent to Australia (PathWest) for analysis by enzyme inhibition assay: 80% upper limit values were established.

Results The median ASO titre in this age group was 220 IU/mL, with the 80th percentile value of 389 IU/mL. The median ADB titre in this age group was 375 IU/mL, with the 80th percentile value of 568 IU/mL.

Conclusions The estimated Ugandan paediatric population standardised 80% upper-limit-of-normal ASO and ADB titres is higher than many global populations. Appropriateness of using population-specific antibody cutoffs is yet to be determined and has important implications for the sensitivity and specificity of rheumatic fever diagnosis.

  • epidemiology
  • cardiology
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Footnotes

  • Twitter @ashabowen

  • Contributors EO and AB conceptualised and designed the study, collected data and drafted the initial manuscript and reviewed and revised the manuscript. MM, JR, ES and EN designed the data collection instruments, coordinated and supervised data collection, and reviewed and revised the manuscript. JA, GK, SK, IOO, LMO and JP collected data and reviewed and revised the manuscript. AB, NH, CTL, TP, CS, RS and MZ contributed to the conception and design of this work and critically reviewed the manuscript for important intellectual content. NdK and JC conceptualised and designed the study, carried out the initial analysis and reviewed and revised the manuscript. All authors gave final approval of this version for publication and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding This work was supported by American Heart Association Grant #17SFRN33670607/Andrea Beaton/2017 and DELTAS Africa Initiative and the General Electric Foundation (donation of equpimtent for echocardiography).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Institutional review board (IRB) approval was obtained from the Research and Ethics Committee at Makerere University School of Medicine, the Children’s National Hospital IRB and the Uganda National Council for Science and Technology IRB.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement De-identified individual participant data can be made availible through direct correspondance with the authors.

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