| Currently there are about8.7million new tuberculosis patients in theworld, and most of them concentrate in developing countries. The TBpatients in China are in second place in the world. The tuberculosisaccounts for64%, and extrapulmonary tuberculosis accounted for about36%in the TB patients. Extrapulmonary tuberculosis accounting for about4%belong to bone and joint tuberculosis. Most of them to joint transferfrom the lungs or other parts of primary tuberculosis. Such diseases arecharacterized by early illness development and poor diagnosis accuracy.Patients often miss the best time for treatment and cause terminal limbdeformities or paraplegia, seriously which affecting the quality of life. Wefound that the reason is due to fewer bacterial content in clinical specimensof bone and joint tuberculosis parts, as lead to the decline of susceptibilityof common smear microscopy’s and bacterial culture’s methods for boneand joint tuberculosis’s diagnosis.With the in-depth study of molecular immunology, the vitro IGRA oftuberculosis’s diagnosis by using IFN-γ has been widely developed andapplied. IFN-γ as a shaped glycoprotein is mainly composed of activatedCD4+Th1, CD8+T cells and NK cells stimulating by antigen andmitogen. It is also critical Th1-type cytokines to control Mycobacteriumtuberculosis infection. The principle of IGRA diagnosising tuberculosis isthat when the body is stimulused by the Mycobacterium of tuberculosis,and Sensitized T lymphocytes meet to the specific antigen, the T cellrelease interferon-γ. Currently IGRA are widely used at home and abroad.IGRA comparing with the tuberculin test has better sensitivity andspecificity, but factors that influence interferon-γ test results have more. Currently, IGRA is mainly used for screening latent tuberculosis, and theresults of interferon-γ in patients with active joint tuberculosis is unknown.To learn more about whole blood interferon-γ testing results of active jointtuberculosis patients from April2012to December2013, the study selectedblood samples of35patients with active joint tuberculosis and35cases ofhealthy in the PLA309Hospital. CFP10/ESAT6fusion protein, Rv2041cprotein, Rv0057/1352fusion protein, Rv1419protein, and Rv1656proteinwere used as stimulating protein. The chemiluminescence enzymeimmunoassay was used to test the content of interferon-γ. The interferon-γof35cases of active joint tuberculosis (TB) and35cases of healthy peoplewas detected. Comparing the difference of the sensitivity, specificity,positive predictive value (PPV), negative predictive value (NPV), positivelikelihood ratio (LR+) and negative likelihood ratio (LR-) of five kinds ofproteins to the diagnostic of active joint tuberculosis. Through research wefound CFP10/ESAT6fusion protein as stimulating protein, the sensitivityand specificity of whole blood IFN-γ detection are77.1%and65.7%. PPVand NPV were62.9%and74.2%. LR+and LR-are2.25and0.348.Rv2041c protein as stimulating protein, the sensitivity and specificity ofwhole blood IFN-γ detection are68.6%and54.3%. PPV and NPV are60%and63.3%. LR+and LR-are1.5and0.579. Rv0057/1352protein asstimulating protein, the sensitivity and specificity of whole bloodinterferon-γ detection are71.4%and57.1%. PPV and NPV were62.5%and66.7%. LR+and LR-are1.67and0.5. Rv1419protein as stimulatingprotein, the sensitivity and specificity of whole blood interferon-γ detectionare74.3%and60.0%. PPV and NPV are65%and70%. LR+and LR-are1.86and0.429. Rv1656protein as stimulating protein, the sensitivity andspecificity of whole blood interferon-γ detection are65.7%and62.9%.PPV and NPV are63.9%and64.7%, LR+and LR-are1.77and0.545.When five kinds of specific proteins stimulated, the index of diagnosis inwhole blood γ-interferon detection is less than150%. Therefor the detection of interferon-γ has certain reference for joint tuberculosis. But itcannot be used as an index of definitive joint tuberculosis diagnisis. |
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