ABSTRACT
This study consisted of 3 closely related parts; the first part included 70 children with pulmonary tuberculosis [TB], aged 2 - 10 years and 20 healthy children as controls. All were subjected to thorough history taking, clinical examination, chest x-ray and tuberculin test. Blood samples were taken to perform glutaraldehyde test and for detection of IgG antibodies against mycobacterium TB by ELISA technique using antigen A60. The sensitivity of glutaraldehyde test was 87.1% and its specificity was 90% with high significance, while the sensitivity of ELISA test was 48.6% and its specificity was 90%. In the second part of the study, sputum samples from 57 children recently diagnosed as having pulmonary tuberculosis, were processed for microscopic examination of smears after staining for acid fast bacilli, culture on Lowenstein-Jensen medium and nested polymerase chain reaction [PCR]. Patients included in this part were divided into 3 groups. In a group of 20 children not-receiving antituberculous therapy yet, the results of smear examination and PCR were identical in 75% of cases. In 10% of cases culture was most sensitive, but in 25% of patients nested PCR was positive even when smear and culture were negative. In a group of 20 children receiving antituberculous therapy for less than six months, PCR positive results were obtained even when both smear and culture were negative. In a group of 17 children receiving antituberculous therapy for more than six months, positive PCR results were detected up to the 7[th] month of therapy. The third part of the study included the HLA [A, B, C loci] phenotyping in 25 cases out of 70 studied in the first-part, and 92 controls. The results showed higher frequency of the following HLA antigens among cases of pulmonary TB than the controls: A25[10], A26[10], AW66, B35, BW55, CW3, CW4 and CW5, and associated with increased relative risk [RR] above one and the etiologic factor for CW4 antigen was 0.408. On the other hand HLA- B5+ B18+ B35, B12, B27 were significantly higher among the controls than the cases. We concluded that glutaraldehyde test can be used as simple, rapid, inexpensive, not tedious test and was positive in cases of TB with malnutrition. Concerning ELISA test, it can be used as rapid serodiagnostic test which is reliable and relatively inexpensive technique for diagnosis of active pulmonary TB in children. Application of nested PCR assay could be used as a follow-up tool in monitoring of pulmonary tuberculosis in children. Regarding HLA antigens the results showed high frequency of the previously mentioned HLA antigens with pulmonary TB, which may indicate, increased susceptibility to pulmonary TB infection. On the other hand, high frequency of other mentioned HLA antigens among controls may indicate a protective effect of these antigens. Anyhow further studies are still needed to be done and on a wide scale to prove the association of HLA antigens and tuberculosis