The Significance In Diagnosing Tuberculous Meningitis By Detecting CFP10 And ESAT-6 In Cerebrospinal Fluid

Objection: Our study improves dot enzyme linked immunosorbant assay (Dot-ELISA), using vacuum pump to aspirate the water in specimens to concentrate them, in order to increase the sensitivity of the method. Use experiments to analyze advantages and disadvantages of the improved method, and to determine the best working condition and the repeatability and the stability of the developed method. Using the improved Dot-ELISA method to detect culture filtrate protein 10 (CFP-10) and 6000 early secretory antigenic target (ESAT-6), two small protein antigen secreted by M.tuberculosis (MTB), in cerebrospinal fluid (CSF). And compare them with other examination and studies in order to judge and analyse their value in diagnosing tuberculous meningitis (TBM).Methods: We detected the same batch of pleural effusion using the old method and the developed method respectively, which include 25 specimens of tuberculous pleural effusion and 31 non-tuberculous and analyzed the difference of the two methods. Determine the repeatability and stability as well as the best working condition by changing the working condition. 111 specimens of cerebrospinal fluid were collected, in which 58 specimens were clinically diagnosed as tuberculous meningitis and 53 as non-tuberlous. CFP10 and ESAT-6 were detected in the cerebrospinal fluid using Dot ELISA method and the results were analyzed.Results: The sensibility of the old method was 76.0%, the improvement method was 92.0%. The sensibility was 96.0% when the best working condition used in the method. There existed statistical difference between the old method and the improvement method as well as using the best working condition (P<0.05). The specificity of the old method was 93.5%. The specificity of improvement method and it in the best working condition was 90.3%. But the specificity doesn't have statistical difference. Blocking experiment which can verify its specificity was positive.The repeatability and stability were good, particularly the repetition rate of the positive results was 100%. The sensitivities of detecting CFP10 and ESAT-6 antigen were 93.1% and 91.4% respectively, and the specificities were 92.5% and 94.3% respectively. The sensitivities and specificities are generally higher compared with those detecting M.tuberculosis or materials of M.tuberculosis, for example, acid-fast staining or mycobacterium tuberculosis culture or PCR.Conclusion: It shows that the developed Dot-ELISA method is sensitive, specific, stable, and can be used to detect specific antigen of mycobacterium tuberculosis and diagnosis of the tuberculosis.Using Dot-ELISA method to detect CFP10 and ESAT-6 in cerebrospinal fluid to diagnose tuberculous meningitis has a high detection rate. The sensitivities and specificities are generally higher compared with those detecting M.tuberculosis or materials of M.tuberculosis. It can be used in diagnosing tuberculous meningitis as a new method which is better than other methods. Our study provided the evidence for the specific antigen of M.tuberculosis used in diagnosing tuberculosis.