[Detection of serum antibody against lipoarabinomannan-B in Mycobacterium tuberculosis (H37Ra)].

The serum antibody to lipoarabinomannan-B(LAM-B) purified from mycobacterium tuberculosis (H37Ra) was tested by ELISA in 250 sera, including sera from patients as follows: tuberculosis 96, tubercular pleurisy 11, renal tuberculosis 2, bone and joint tuberculosis 33, tubercular meningitis 16, pulmonary cancer 22, leprosy 20 and normal subjects 50. The positive rate of pulmonary tuberculosis is 69.8%, which is of a similar extent in sera from patients with tuberculosis of miscellaneous organs to be tested except tubercular meningitis, in which only 18.8% positive rate was observed, indicating the blockage of antibody releasing from pathologic foci into blood stream by blood-brain barrier. The positive rates of leprosy and normal subjects are 50.0% and 2.0% respectively. No antibody was found among 22 patients with pulmonary cancer. It is suggested that the existence of an active tubercular lesion in the host might be the basic prerequisite for a positive LAM-B antibody detection. Although LAM-B is a common antigen of both mycobacterium tuberculosis and mycobacterium leprae, the low prevalence of leprosy in China makes little influence of the practicability of using this ELISA in epidemiological study and in clinic as a adjutant tool for tuberculosis diagnosis and differential diagnosis.