Serodiagnosis of childhood tuberculosis by ELISA.
OBJECTIVE
Diagnosis of childhood tuberculosis remains an enigma despite many recent technological developments. The present study has been taken up with the aim to assess the diagnostic potential of mycobacterium tuberculosis excretory-secretory ES-31 antigen and affinity purified anti ES-31 antibodies in the serodiagnosis of different spectrum of childhood tuberculosis.


METHODS
Mycobacterium tuberculosis H37Ra excretory-secretory antigen (ES-31) and affinity purified goat anti ES-31 antibodies were used in stick penicillinase ELISA for IgG antibody detection and stick Sandwich penicillinase ELISA for detection of circulating free and immune complexed antigen in the sera of 230 children.


RESULTS
Analysis of tubercular antibody, circulating free and immune complexed antigen (CIC-Ag) was done in both pulmonary and extrapulmonary form of childhood tuberculosis and overall sensitivity of 81.4% with a specificity of 93% was achieved for detection of antitubercular IgG antibodies. Of the five cases of pulmonary tuberculosis showing absence of IgG antibody, 3 showed the presence of CIC-Ag and one was found positive for both free and CIC-Ag. Similarly out of 8 cases of extrapulmonary childhood tuberculosis missed by IgG detection 5 were found to be positive for CIC-Ag and 1 showed the positive reaction for both free and immune complexed antigens.


CONCLUSIONS
IgG antibody to excretory-secretory antigen ES-31 is found to be having good specificity with acceptable sensitivity in detecting different forms of childhood tuberculosis. Further detection of circulating free and/or immunecomplexed antigen can be used as an adjunct tool in the diagnosis of childhood tuberculosis.
Jamnalal Bajaj Tropical Disease Research Centre, Department of Biochemistry, Mahatma Gandhi Institute of Medical Sciences, Sevagram, Wardha, Maharashtra, India.
A S
AS
Bhatia
Sonika
S
Gupta
Neeraj
N
Shende
Satish
S
Kumar
B C
BC
Harinath
D000907:Antibodies, Bacterial / Q000032:analysis*; D000936:Antigen-Antibody Complex / Q000032:analysis; D000942:Antigens, Bacterial / Q000032:analysis*; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D010372:Pediatrics / Q000379:methods; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D014376:Tuberculosis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology
D000907:Antibodies, Bacterial; D000936:Antigen-Antibody Complex; D000942:Antigens, Bacterial