Use of enzyme linked immunospot assay [ELISpot] for monitoring treatment response of pulmonary tuberculosis patients

Tuberculosis [TB] remains one of the major causes of death from a single infectious agent worldwide. The rapid emergence of drug resistant mycobacteria has strengthened the demand for rapid methods for detection of mycobacteria in clinical samples. As prevention of tuberculosis relies on the early detection and cure of the infectious cases, current efforts are focused upon improving the rapidity of identification of Mycobacterium tuberculosis, allowing prompt initiation of appropriate therapy. The rapid enzyme linked immunospot assay [ELISpot] method was developed in the late 1990s based on the numbers of spots made by interferon gamma producing T cells stimulated by culture filtrate protein-10 [CFP-10] or early secretory antigenic target-6 [ESAT-6]. Therefore, a T-cell response to these antigens could in theory serve as a specific marker of M. tuberculosis infection. Is to assess the potential utility of ELISpot assay for monitoring treatment response of pulmonary tuberculosis patients. The study was done on 30 patients diagnosed as pulmonary tuberculosis on clinical, radiological and bacteriological bases. They were collected from Zagazig Chest Hospital and Zagazig University Hospitals from January 2010 to January 2011. A total of 15 healthy volunteers were enrolled in this study as control subjects. The following were performed for all patients before treatment initiation: full history taking, complete clinical examination, chest X-ray, postero-anterior and lateral views, tuberculin skin test [TST] by Mantoux technique, and routine laboratory investigations. Three successive sputum samples for sputum smear Ziehl-Neelsen [Z-N] staining and sputum collection for Mycobacterium culture on Lowenstein-Jensen media [LJ. Media] were done. Collection of 2 ml heparinized blood for enzyme linked immunospot assay [ELISpot] was done. All patients received four antituberculous drugs, isoniazid, rifampicin, pyrazinamide and ethambutol, for the initial 2 months. After 2 months of therapy; another three successive sputum samples for sputum smear Ziehl-Neelsen [Z-N] staining and sputum collection for Mycobacterium culture on Lowenstein-Jensen media were done. Collection of 2 ml heparinized blood for enzyme linked immunospot assay [ELISpot] was done. The results of this study showed that all patients were complaining of cough and expectoration. Tuberculin skin test was positive in 18 patients [60%]. Most patients [46.6%] had moderately advanced disease as regards the radiological extent. It was found that the median INF-y ELISpot response to ESAT-6 was significantly decreased after 2 months of antituberculosis therapy. The number of pre-treatment ESAT-6 ELISpot count in patients with positive tuberculin skin test was significantly higher than those with negative tuberculin skin test [P < 0.01]. As regards bacillary load, a statistical significant difference between patients with AFB+ + + and patients with [AFB +, AFB + +] as regards pre-treatment ELISpot count was recorded. Higher statistical significant difference in patients with AFB +, AFB + + and AFB + + 4- pre and post treatment ESAT-6 ELISpot count was found. It was found that the number of pre-treatment ESAT-6 ELISpot count in patients with cavitary lesion was higher than those without cavitary lesion and the difference was highly significant [P = 0.01]. As regards radiological extent, it was found that the number of pre-treatment ESAT-6 ELISpot count in patients with far advanced disease was higher than patients with minimal or moderately advanced disease. Also, after 2 months of therapy the number of ESAT-6 ELISpot count in patients with far advanced disease showed more decline than patients with minimal or moderately advanced disease. It was found that ELISpot assay sensitivity, specificity, positive predictive value and negative predictive value in relation to L.J. media were 93.3%, 100%, 100% and 88.2%, respectively. ELISpot assay may be used as a useful tool in the diagnosis of pulmonary tuberculosis. The decrease in the M. tuberculosis-specific T cell responses following 2 months of successful antituberculosis therapy may have a clinical value as a supplemental tool for the monitoring treatment response of pulmonary tuberculosis patients

Accuracy assessment of moderate resolution image spectroradiometer products for dust storms in semiarid environment

Dust storms are strongly and negatively associated with the annual cycle of rainfall and coincide with the west and southwesterly winds in west and south west of Iran. Accuracy assessment of particulate matter products of moderate resolution image spectroradiometer was studied in this research. Moderate resolution image spectroradiometer products consist of aerosol optical thickness, its corresponding image red, green and blue and moderate resolution image spectroradiometer/ terra calibrated radiances 5 minutes L1B swath 1 km, which shows the environmental information at terrestrial, atmospheric and ocean phenomenology. Daily aerosol optical thickness data retrieved from moderate resolution image spectroradiometer from May 2009 to May 2010 were compared with the amount of particulate matter measured at ground in Sanandaj, Iran, using non-linear correlation coefficient. Results showed that the moderate resolution image spectroradiometer image / terra calibrated radiances 5 minutes L1B swath 1 km is able to detect dust storms distribution and their blowing direction over study area clearly. The air quality conditions obtained in with dust storm period were unhealthy and correlation coefficients between moderate resolution image spectroradiometer aerosol optical thickness and particulate matter concentration in this period were higher than without dust storm period. The moderate resolution image spectroradiometer aerosol optical thickness values lower than 0.1 were acquired uncertainty level. Comparison of moderate resolution image spectroradiometer images/ terra calibrated radiances 5 minutes L1B swath 1 km and image red, green and blue showed that moderate resolution image spectroradiometer has limitation in retrieval of aerosol optical thickness from the dust storm with high concentration of particulate matter. This study reveals that the algorithm which is applied to refine the aerosol optical thickness is not able to recognize the amount of particulate matter in low and very high concentrations sensitively. No study has previously been conducted to investigate the accuracy of the moderate resolution image spectroradiometer particulate matter products