The Value Of Detecting The Mycobacterial Antigens In Monocyte Of The Cerebrospinal Fluid For The Diagnosis Of Tuberculous Meningitis

The incidence of tuberculosis is becoming higher and higher because of many different factors such as the prevalence of multiple-drug resistance tuberculosis, the infections of human immunodeficiency virus and poverty, and there are also more and more patients with tuberculous meningitis (TBM) step by step. TBM is one of the most common forms of central nervous system infections, associated with high mortality and disability. It is well known that the key to change this situation is the early diagnosis and early treatment, whereas there is no reliable and pragmatic method that can meet the needs for early diagnosis. Mycobacterium tuberculosis (MTB) is parasitic bacterium in cell and parasitizes in mononuclear macrophage of its host when it invades the living body. After the living body was infected with MTB, in contrast with mycobacterial antibody, it is the mycobacterial antigens that emerge in the organism at first. The detection of the mycobacterial antigens is not interfered with the immune state of the host. The purpose of this study is to estimate the value of detecting the mycobacterial antigens in monocyte of the cerebrospinal fluid (CSF)for the diagnosis of TBM ,and provide an available method for it.To seek an ideal assay for the diagnosis of TBM, by means of immunocytochemistry, the detection of (purified protein derivative) PPD and early secretary antigenic target 6(ESAT-6) in the mononuclear cells in CSF and peripheral blood(PB)was applied to 85 patients with central nervous system infections by clinical diagnosis. In this study, we considered the generally acceptable clinical diagnostic standard of TBM as gold standard and divided the patients into the disease group of TBM (45 cases) and control group(40 cases), estimated the value of detecting the PPD and ESAT-6 in monocyte of CSF and PB for the diagnosis of TBM by epidemiology method.Results:(1) Positive staining of the PPD was seen in thirty-nine TBM CSF samples and thirteen in control group, and positive staining of the ESAT-6 was seen in thirty-nine CSF specimens of TBM and six in control group. (2) Positive staining of the PPD was seen in eleven PB samples of TBM and zero in control group, and this phenomenon emerged in detecting the ESAT-6. (3) The assay to study the PPD in CSF carries a sensitivity of 86.7% and a specificity of 87.5%, and the ESAT-6 has a equal sensitivity compared with the PPD and has a specificity of 92.5%. (4) The assay to study the PPD and the ESAT-6 in PB have a same result, and their sensitivities are 24.4% and specificities are 100%. (5) The percentage of the positive staining cells of the PPD and the ESAT-6 in CSF and PB samples of TBM were higher significantly than those in controls(P<0.001). (6) The percentage of the positive staining cells of the PPD and the ESAT-6 in CSF samples of TBM were higher significantly than those in PB(P<0.001).Conclusions: The diagnostic assays to detect the mycobacterial antigens in monocyte of the CSF by means of immunocytochemistry is affordable, sensitive, and specific, and can be used for the diagnosis of TBM, while the sensitivity of detecting the mycobacterial antigens in monocyte of the PB for the diagnosis TBM is lower, and this method is not acceptable.