title: High numbers of interferon-gamma-producing T cells and low titers of anti-tuberculous glycolipid antibody in individuals with latent tuberculosis.
abstract: Latent tuberculosis infection (LTBI) is defined as an infection with Mycobacterium tuberculosis (MTB) without clinical, bacteriological, or radiological findings, and its early diagnosis is essential for eradication of tuberculosis. To identify LTBI, we measured the numbers of interferon-gamma producing T cells, based on the ELISPOT assay, and the antibody titers in the sera to tuberculous glycolipid antigen (TBGL-Ab). Seventeen culture-confirmed TB patients, 13 controls from TB endemic areas (EC) and 13 controls from TB non-endemic areas (NEC) were enrolled. Peripheral blood mononuclear cells (2.5 x 10(5) per well) were cultured on plates precoated with antibody against interferon-gamma. ELISPOT response was defined as positive when the MTB-specific antigen-containing wells showed at least 6 spots and twice numbers of spots than negative control wells. ELISPOT responses were positive in 15 (88%), 8 (62%) and 4 (31%) subjects of TB, EC and NEC groups, respectively. The ELISPOT data differ between TB and NEC groups (p < 0.01) but not between TB and EC groups. In contrast, TBGL-Ab titers were elevated (> 2.0 U/ml) in 12 TB patients (71%), but only in one subject (8%) each from EC and NEC groups. These results indicate the high prevalence of LTBI in EC. In conclusion, LTBI is associated with positive ELISPOT assay and the low titer of TBGL-Ab, while positive results both in ELISPOT and TBGL-Ab assays indicate active TB. The low titer of TBGL-Ab is a helpful marker to identify LTBI in ELISPOT-positive individuals in TB endemic areas.
authors.affiliation: Division of Emerging Infectious Diseases, Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Heinner
authors.initials: H
authors.lastname: Guio
authors.forename: Yugo
authors.initials: Y
authors.lastname: Ashino
authors.forename: Hiroki
authors.initials: H
authors.lastname: Saitoh
authors.forename: Umme Ruman
authors.initials: UR
authors.lastname: Siddiqi
authors.forename: Masako
authors.initials: M
authors.lastname: Mizusawa
authors.forename: Peng
authors.initials: P
authors.lastname: Xiao
authors.forename: Alonso
authors.initials: A
authors.lastname: Soto
authors.forename: Andros
authors.initials: A
authors.lastname: Theo
authors.forename: Toshio
authors.initials: T
authors.lastname: Hattori
mesh_terms: D000328:Adult; D000906:Antibodies / Q000276:immunology*; D005260:Female; D006017:Glycolipids / Q000276:immunology*; D006801:Humans; D007118:Immunoassay; D007371:Interferon-gamma / Q000096:biosynthesis*; D055985:Latent Tuberculosis / Q000276:immunology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology
chemical_list: D000906:Antibodies; D006017:Glycolipids; D007371:Interferon-gamma