Clinical evaluation of a homemade enzyme-linked immunospot assay for the diagnosis of active tuberculosis in China.
The rapid diagnosis of smear-negative pulmonary tuberculosis (TB) and extrapulmonary TB is a significant problem in clinical practice. We evaluated the usefulness of a homemade enzyme-linked immunospot (ELISPOT) assay for the diagnosis of active TB in China. Seventy-eight healthy volunteers, 60 patients with active TB, and 32 patients with non-TB diseases were evaluated by tuberculin skin test (TST), an ELISPOT assay using a recombinant CFP-10/ESAT-6 fusion protein (rCFP-10/ESAT-6) as a stimulant, and T-SPOT-TB assay. The spot-forming cells (SFC) from 78 healthy subjects containing both PPD-positive and -negative persons was 3.7 ± 6.5. Among 31 diagnosed TB patients, the ELISPOT assay had a sensitivity of 67.7%, compared to a sensitivity of 77.4% for the T-SPOT-TB assay. The ELISPOT assay was more sensitive in smear-positive TB cases (76.9%) than in smear-negative TB cases (61.1%), while T-SPOT-TB had roughly similar sensitivities in smear-positive (76.9%) and smear-negative TB cases (77.8%). The specificity was 90.6% for ELISPOT and 78.1% for T-SPOT-TB among 32 subjects with non-TB diseases. The SFC of TB cases was significantly higher than that of non-TB disease cases, and the SFC of smear-positive TB cases was significantly higher than that of smear-negative TB cases (P < 0.01). We confirmed that the homemade ELISPOT assay appears more specific for the diagnosis of active TB than T-SPOT-TB. ELISPOT assay may be a useful method for the rapid diagnosis of active TB, especially for cases of smear-negative TB.
Wu
Xueqiong
X
Institute for Tuberculosis Research, The 309th Hospital of Chinese PLA, Beijing, 100091, China. wu-xueqiong@263.net
Li
Qiaoke
Q
Liang
Yan
Y
Yang
Yourong
Y
Zhang
Junxian
J
Liang
Jianqin
J
Li
Lan
L
Tang
Fakuan
F
Wang
Ansheng
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000032:analysis* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000032:analysis* / Q000302:isolation & purification; D002681:China / Q000453:epidemiology; D058501:Enzyme-Linked Immunospot Assay / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000032:analysis* / Q000302:isolation & purification; D012189:Retrospective Studies; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*; D055815:Young Adult
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D011993:Recombinant Fusion Proteins