| Title | Clinical application of a rapid lung-orientated immunoassay in individuals with possible tuberculosis. |
| Link | http://thorax.bmj.com/cgi/reprint/63/1/67 |
| Attached Resource |  |
| Full text (for search) | |
| Author(s) | Breen RA; Barry SM; Smith CJ; Shorten RJ; Dilworth JP; Cropley I; McHugh TD; Gillespie SH; Janossy G; Lipman MC. |
| Abstract | BACKGROUND:
Immunological ex vivo assays to diagnose tuberculosis (TB) have great potential but have largely been blood-based and poorly evaluated in active TB. Lung sampling enables combined microbiological and immunological testing and uses higher frequency antigen-specific responses than in blood.
METHODS: A prospective evaluation was undertaken of a flow cytometric assay measuring the percentage of interferon-gamma synthetic CD4+ lymphocytes following stimulation with purified protein derivative of Mycobacterium tuberculosis (PPD) in bronchoalveolar lavage fluid from 250 sputum smear-negative individuals with possible TB. A positive assay was defined as >1.5%.
RESULTS: Of those who underwent lavage and were diagnosed with active TB, 95% (106/111) had a positive immunoassay (95% CI 89% to 98%). In 139 individuals deemed not to have active TB, 105 (76%) were immunoassay negative (95% CI 68% to 82%). Of the remaining 24% (34 cases) with a positive immunoassay, a substantial proportion had evidence of untreated TB; in two of these active TB was subsequently diagnosed. Assay performance was unaffected by HIV status, disease site or BCG vaccination. In culture-positive pulmonary cases, response to PPD was more sensitive than nucleic acid amplification testing (94% vs 73%). The use of early secretory antigen target-6 (ESAT-6) responses in 71 subjects was no better than PPD, and 19% of those with culture-confirmed TB and a positive PPD immunoassay had no detectable response to ESAT-6.
CONCLUSIONS: These findings suggest that lung-orientated immunological investigation is a potentially powerful tool in diagnosing individuals with sputum smear-negative active TB, regardless of HIV serostatus. |
| Peer Reviewer | |
| Publisher | BMJ |
| Source | Thorax online |
| Publication Type | Research study |
| Category | Investigation, Management |
| Level of Evidence | Evidence cited |
| Coverage | National |
| Format | Pdf |
| Language | English |
| Access Rights | Free |
| Date of publishing | 03/01/2008 |
| Date of last review by us | 03/05/2008 |