Anti-Kp 90 IgA antibodies in the diagnosis of active tuberculosis.
BACKGROUND
Accurate diagnosis of active tuberculosis (TB) has been difficult historically, yet a great demand persists for a rapid and reliable diagnostic method. Detection of Mycobacterium tuberculosis anti-Kp 90 IgA antibodies is one of the more novel techniques.


OBJECTIVE
To evaluate the diagnostic value of a recently developed enzyme-linked immunosorbent assay (ELISA) test, which detects IgA antibodies against M tuberculosis Kp 90 antigen, and to compare the results with conventional diagnosis and the polymerase chain reaction (PCR) method.


METHODS
Serum, ethylenediaminetetraacetic acid (EDTA)-blood, and body fluid samples were obtained from 51 patients with active TB and 71 control subjects. The clinical diagnosis of TB was supported by a positive culture (n = 6), detection of acid-fast bacilli on smear (n = 35), or both (n = 10).


RESULTS
IgA antibodies were detected in sera and/or body fluid samples from 82% of patients with TB and 10% of controls. M tuberculosis DNA was detected in body fluid sample of 96% and blood sample of 49% of patients with TB by PCR. None of the blood and 5.6% of the body fluid specimens from controls were PCR-positive.


CONCLUSIONS
Anti-Kp 90 IgA antibodies were detected using ELISA in 78% of serum and 69% of body fluids from patients with TB, therefore, this test is promising for the diagnosis of active TB and appears to be more reliable, particularly for body fluid samples.
Arikan
S
S
Hacettepe University School of Medicine, Ankara, Turkey.
Tuncer
S
S
Us
D
D
Unal
S
S
Ustaçelebi
S
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000907:Antibodies, Bacterial / Q000032:analysis*; D000942:Antigens, Bacterial; D004269:DNA, Bacterial / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
D000888:Antibodies, Anti-Idiotypic; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D004269:DNA, Bacterial; D007070:Immunoglobulin A; C115754:antigen Kp 90