Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

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Original article / research
Table of Contents - Year : 2017 | Month : June | Volume : 11 | Issue : 6 | Page : DC10 - DC11

Salivary Anti-50 kDa Antibodies as a Useful Biomarker for Diagnosis of Typhoid Fever DC10-DC11

Nur Eliyana Mohd Redhuan, Kai Ling Chin, Azreen Syazril Adnan, Asma Ismail, Prabha Balaram, Kia Kien Phua

Correspondence
Dr. Kia Kien Phua,
Professor, Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Minden-11800, Penang, Malaysia.
E-mail: kkphua7@gmail.com

Introduction: Typhoid fever remains a scourge of humanity, especially in developing and under-developed countries due to poor sanitation and food hygiene. Diagnostic methods available for detection of this disease are not satisfactory due to a lack of sensitive, specific, rapid and convenient diagnostic test kits available in the market.

Aim: To evaluate the feasibility of a Dot-EIA method for Ig-class specific salivary antibody detection for diagnosis of typhoid fever.

Materials and Methods: Paired saliva and serum samples were collected in the year 2010 from patients and normal volunteers in Hospital Universiti Sains Malaysia, Kelantan, Malaysia, which is endemic for typhoid fever. A total of 11 culture-confirmed typhoid fever patients, 43 non-typhoid fever patients and 53 normal human control subjects were evaluated for antibodies against a 50 kDa antigen specific for Salmonella Typhi using Dot-EIA.

Results: Ig class-specific screening of the test samples showed a higher sensitivity for IgA (90.9%) compared to either IgG (72.7%) or IgM (72.7%) antibodies in saliva, but for serum, IgG (90.9%) had a higher degree of sensitivity compared to IgA (36.4%) and IgM (63.6%). Combining all isotypes (IgA, IgG or IgM), serum showed a higher sensitivity (100.0%) compared to saliva (90.9%). Also, the specificity for serum (100.0%) was much higher than saliva (85.4%).

Conclusion: Salivary IgA anti-50kDa antibody was found to be more suitable biomarker for routine screening, whereas serum IgG was more suitable for confirmatory test as it has higher specificity. Nevertheless, salivary IgA Dot-EIA is a convenient method for rapid testing, such as for Point-of-Care Diagnostics (POCD) and field epidemiological studies, due to its non-invasive nature and ease of use.