Serum and bronchoalveolar IgG against A60 and 38 kDa antigens in the diagnosis of tuberculosis.
METHODS
The ELISA test is generally accepted for serodiagnosis of tuberculosis. Its sensitivity and specificity depend on the antigen used and data are not always concordant. In some patients suspected of tuberculosis, sarcoidosis or lung cancer, bronchoalveolar lavage (BAL) is performed. BAL fluid (BALF) contains immunoglobulins--their source is transudation from the serum but local IgG synthesis of IgG is not excluded.


OBJECTIVE
The comparison of BALF versus serum in the serodiagnosis of pulmonary tuberculosis, and its differentiation from sarcoidosis and lung cancer.


METHODS
The IgG against A60 and 38 kDa antigens in serum and BALF were measured using the commercially available IgG EIA kits. The study included 13 tuberculous patients, 8 patients with sarcoidosis, 10 patients with lung cancer and 9 healthy volunteers.


RESULTS
In the serum studies the sensitivity of the assays did not exceed 40% and 60% in the estimation of IgG 38 kDa and IgG A60, respectively. The specificity of both assays was similar: 81% (IgG 38 kDa) and 69-75% (IgG A60). In BALF studies the sensitivity of the IgG 38 kDa assay was 50% and its specificity was 44%. The ranges of the IgG A60 concentrations in BALF were similar in all subject groups.


CONCLUSIONS
In differentiation between tuberculosis, sarcoidosis and lung cancer, the measurement of IgG against A60 and 38 kDa antigens in serum is more useful than that in BALF.
Grubek-Jaworska
H
H
Department of Pneumology, Warsaw Medical School, Poland.
Zwolska
Z
Z
Droszcz
P
P
Rybus
L
L
Dabrowski
A
A
Droszcz
W
W
D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis; D003937:Diagnosis, Differential; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000032:analysis* / Q000097:blood; D008074:Lipoproteins; D008175:Lung Neoplasms / Q000175:diagnosis; D008875:Middle Aged; D017565:Sarcoidosis, Pulmonary / Q000175:diagnosis; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
C075966:Ag38 antigen, Mycobacterium tuberculosis; D000942:Antigens, Bacterial; D007074:Immunoglobulin G; D008074:Lipoproteins; C055539:mycobacterial A60 antigen