M. Amicosante et al., EVALUATION OF A NOVEL TUBERCULOSIS COMPLEX-SPECIFIC 34 KDA PROTEIN INTHE SEROLOGICAL DIAGNOSIS OF TUBERCULOSIS, The European respiratory journal, 8(12), 1995, pp. 2008-2014
Tuberculosis (TB) serological testing with antigen complexes, although
very sensitive, is not always as specific due to reactive serum antib
odies in patients with inactive TB or nontuberculous infections. Since
the use of recombinant M. tuberculosis proteins may enhance specifici
ty, this study was designed to evaluate a novel 34 kDa tuberculosis co
mplex-specific protein as a component of an antigen panel of recombina
nt proteins. Seventy patients with active TB (41 positive and 29 negat
ive for acid-fast bacilli (AFB) in sputum) were evaluated, in comparis
on with 30 tuberculin purified protein derivative skin test positive (
PPD+) and 30 PPD- normals, 20 subjects with inactive TB and 20 PPD+ su
bjects with nontuberculous pneumonia as controls. Serum antibody level
s were quantified using enzyme linked immunosorbent assay (ELISA) test
s with MS2-34, a fusion protein comprising the NH2-terminal 16 kDa of
the 34 kDa protein, a recombinant 38 kDa protein (p38), and PPD. Using
MS2-34 and p38 as an antigen panel in active TB patients yielded high
er sensitivity and negative predictive value (sensitivity 86%; negativ
e predictive value 91%) than using PPD (sensitivity 66%; negative pred
ictive value 81%). Importantly, the MS2-34+p38 panel yielded a higher
sensitivity (83%) than PPD (66%) in the subset of AFB- active TB patie
nts. Thus, this novel protein increases sensitivity and specificity of
serological testing for TB when used in panels of recombinant protein
s.