title: IgA response to ESAT-6/CFP-10 and Rv2031 antigens varies in patients with culture-confirmed pulmonary tuberculosis, healthy Mycobacterium tuberculosis-infected and non-infected individuals in a tuberculosis endemic setting, Ethiopia.
abstract: Little attention has been given to the role of antibodies against Mycobacterium tuberculosis (Mtb) infection. We have compared the levels of IgA and IgG against ESAT-6/CFP-10 and Rv2031c antigens in sera of patients with culture-confirmed pulmonary tuberculosis (PTB), healthy Mtb-infected and non-infected individuals in endemic TB settings. Venous blood samples were collected from 166 study participants; sera were separated and assayed by an enzyme-linked immunosorbent assay (ELISA). QuantiFERON-TB Gold In-Tube (QFTGIT) assay was used for the screening of latent TB infection. The mean optical density (OD) values of IgA against ESAT-6/CFP-10 and Rv2031 were significantly higher in sera of patients with culture-confirmed PTB compared with healthy Mtb-infected and non-infected individuals (P < 0.001). The mean OD values of IgG against ESAT-6/CFP-10 and Rv2031 were also significantly higher in sera of patients with culture-confirmed PTB compared with healthy Mtb-infected and non-infected individuals (P < 0.05). The mean OD values of IgA against both antigens were also higher in sera of healthy Mtb-infected cases compared with non-infected individuals. There were positive correlations (P < 0.05) between the level of IFN-γ induced in QFTGIT assay and the OD values of serum IgA against both antigens in healthy Mtb-infected subjects. This study shows the potential of IgA response against ESAT-6/CFP-10 and Rv2031 antigens in discriminating clinical TB from healthy Mtb-infected and non-infected cases. Nevertheless, further well-designed cohort study is needed to fully realize the full potential of this diagnostic marker.
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia; Department of Community Medicine, Institute for Health and Society, University of Oslo, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Legesse
authors.forename: G
authors.initials: G
authors.lastname: Ameni
authors.forename: G
authors.initials: G
authors.lastname: Medhin
authors.forename: G
authors.initials: G
authors.lastname: Mamo
authors.forename: K L M C
authors.initials: KL
authors.lastname: Franken
authors.forename: T H M
authors.initials: TH
authors.lastname: Ottenhoff
authors.forename: G
authors.initials: G
authors.lastname: Bjune
authors.forename: F
authors.initials: F
authors.lastname: Abebe
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D005002:Ethiopia; D005260:Female; D006801:Humans; D016056:Immunodominant Epitopes / Q000276:immunology; D007070:Immunoglobulin A / Q000097:blood* / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D007371:Interferon-gamma / Q000097:blood; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000276:immunology* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D015415:Biomarkers; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D016056:Immunodominant Epitopes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007371:Interferon-gamma