Evaluation of total immunoglobulin G and subclass antibodies in an enzyme-linked immunosorbent assay for serodiagnosis of human amebic liver abscess

Penchom Janwan; Lakkhana Sadaow; Rutchanee Rodpai; Hiroshi Yamasaki; Vor Luvira; Wattana Sukeepaisarnjaroen; Amnat Kitkhuandee; Krisada Paonariang; Oranuch Sanpool; Patcharaporn Boonroumkaew; Tongjit Thanchomnang; Toshihiro Mita; Pewpan M Intapan; Wanchai Maleewong

doi:10.7717/peerj.14085

Evaluation of total immunoglobulin G and subclass antibodies in an enzyme-linked immunosorbent assay for serodiagnosis of human amebic liver abscess

PeerJ. 2022 Sep 29:10:e14085. doi: 10.7717/peerj.14085. eCollection 2022.

Authors

Penchom Janwan^{1

2}, Lakkhana Sadaow^{3

4}, Rutchanee Rodpai^{3

4}, Hiroshi Yamasaki^{5

6}, Vor Luvira⁷, Wattana Sukeepaisarnjaroen⁸, Amnat Kitkhuandee⁷, Krisada Paonariang⁷, Oranuch Sanpool^{3

4}, Patcharaporn Boonroumkaew^{3

4}, Tongjit Thanchomnang^{4

9}, Toshihiro Mita⁶, Pewpan M Intapan^{3

4}, Wanchai Maleewong^{3

4}

Affiliations

¹ Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, Thailand.
² Hematology and Transfusion Science Research Center, Walailak University, Nakhon Si Thammarat, Thailand.
³ Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
⁴ Mekong Health Science Research Institute, Khon Kaen University, Khon Kaen, Thailand.
⁵ Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
⁶ Department of Tropical Medicine and Parasitology, Juntendo University School of Medicine, Tokyo, Japan.
⁷ Department of Surgery, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
⁸ Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
⁹ Faculty of Medicine, Mahasarakham University, Maha Sarakham, Thailand.

Abstract

Background: Amebic liver abscess (ALA) caused by Entamoeba histolytica is usually diagnosed based on its clinical symptoms, medical imaging abnormalities of the liver, and serological tests, the most common being the enzyme-linked immunosorbent assay (ELISA). For more than three decades, no investigation has evaluated the diagnostic performance of immunoglobulin G (IgG) subclasses in the serodiagnosis of ALA. Herein, we assessed the efficiencies of anti-amebic IgG and IgG subclasses for diagnosing ALA.

Methods: A serological ELISA-based test was performed to assess its diagnostic performance using a total of 330 serum samples from ALA patients (n = 14), healthy individuals (n = 40), and patients with other diseases (n = 276).

Results: ELISA targeting the total IgG antibody to E. histolytica antigen exhibited 100% sensitivity 95% CI [76.8-100.0] and 97.8% specificity 95% CI [95.5-99.1], whereas the assay targeting IgG1 showed the same sensitivity (100% 95% CI [76.8-100.0]) and a slightly higher specificity (99.1% 95% CI [97.3-99.8]). The other IgG subclasses (IgG2, IgG3, and IgG4) displayed a lower sensitivity and specificity. The sensitivity and specificity did not significantly differ between tests measuring total IgG and IgG1 (Exact McNemar's test; p > 0.05), with a concordance of 98.2%, represented by a Cohen's kappa of 0.83 (p < 0.001), indicating almost perfect agreement.

Conclusion: ELISA targeting IgG1 can provide valuable information to clinicians in differentiating ALA from other parasitic diseases, cancers, cirrhosis, and viral hepatitis. However, enzyme-conjugated anti-human total IgG is cheaper than anti-human IgG subclasses. Therefore, we suggest that total IgG-based ELISA is sufficient for the routine serodiagnosis of human ALA and possibly other clinical manifestations of invasive amebiasis.

Keywords: Amebic liver abscess; Entamoeba histolytica; Enzyme-linked immunosorbent assay; Immunoglobulin G subclasses; Serodiagnosis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Antibodies, Protozoan / analysis
Enzyme-Linked Immunosorbent Assay / methods
Humans
Immunoglobulin G / analysis
Liver Abscess, Amebic* / diagnosis
Serologic Tests / methods

Substances

Immunoglobulin G
Antibodies, Protozoan

Grants and funding

This study was supported by the National Science, Research and Innovation Fund, Thailand (WM); Khon Kaen University, Research and Graduate Studies Affairs, (PJ, OS, PMI and WM, Research Program); and the Faculty of Medicine, Khon Kaen University (PMI and WM, grant number RG63301). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.