الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
Today TB has re-emerged as an important Public Health Problem over the World, and considered one of the most important infectious diseases of mankind. Globally there are 8.4 million new cases of TB a year worldwide, and about 80 of them are in their productive years (15-59 years) with 3.1 million deaths per year. M. tuberculosis is not only one of the oldest microbial threats to human health, it is also one of the most formidable. Recently in Egypt WHO reported 11.763 cases diagnosed as TB, whereas in Yemen, 12.383 cases were reported. Therefore many treatment regimens for TB have been adopted, but recent outbreakes of virulent multi-drug resistant strains underscore the need for noval approaches to treat and prevent tuberculosis including the use of immunotheraputic modalities that enhance normal antimycobacterial defenses. There are many factors which likely lead to the development of failure or drug-resistant-TB in HIV negative persons; they include the difference in the virulence, association of other diseases (as nocardisosis) with tuberculosis, and qualitative or quantitative reduction in immune response. The immunity against mycobacteria is complicated and completely not understood, but there are some evidence that persistence and/or progression of TB may be associated with the level of cytokines that produced by T-cells. Some data demonstrated the importance of some cytokines as IL-2 which play a crucial role in controlling and regulating TB. This observation may redirect the function of activated T-helper (Th) cells and established either Th1 or Th2. IL-2 behaves as chemical mediator in immune responses acting either as short-range messengers during interaction between cells or, like hormones, circulating in the blood and effecting distant cells, remotes from its production site. It also increase the cytotoxic capacity of natural killer cells, when NK cells are activated with IL-2, they start to produce IFN-? which also known to increase the cytotoxicity of the cells. The study aimed to evaluate some biological factors such as CD4-cells counts, and determination of serum IL-2 level, in addition to study the association between tuberculous cases and nocardiosis. This study was conducted on 200 subjects (a hundred from Egypt, and the other hundred from Yemen). From them, 160 patients divided into three categories: Group I: Included 80 patients (40 patients from each country) with persistent smear positive for AFB, and under therapy from 3-6 months. Group II: Included 40 patients (20 patients from each country) diagnosed as a new healed pulmonary TB. Group III: Included 40 patients (20 patients from each country) diagnosed as other pulmonary diseases. Healthy group IV: Included 40 healthy individuals (20 subjects from each country) as control group. 160 sputum samples were collected from patients (cases and healed cases), and subjected to: direct examination by Ziehl Neelsen stain, and modified kinyoun stain, culture on Lowenstein Jensen medium, sabouraud’s dextrose agar, and only 30 sputum samples from the first group were inoculated into Septi Chek medium, and identificated. Blood samples were collected from all subjects. These samples divided into two portions. The first portion was collected into EDTA tube for CD4 counting, while the other portion was collected into a centrifuge tube for IL-2 analysis. A portion of sputum sample was subjected to direct microscopical examination using Ziehl Neelsen Stain, and modified kinyoun stain. Tubercle bacilli are acid fast red rods, appear singly or in groups. Sputum samples were digested and decontaminated using petroff’s method before inoculation on those previous mentioned media. As for Mycobacteria, the inoculated LJ media were incubated at 37?C for 8 weeks, examined twice/weekly. Tubercle baclli are slow growers and grow at 37?C. colonies appear as rough buff to yellowish in colour, and tough when picked off. Also inoculated Septi check system media were incubated at 37?C for 8 weeks, examined daily during the first weeks, weekly for eight weeks or until growth was observed. A subculture was done and colonies were identified by sensitivity to paranitrobenzoic acid (PNB) and niacin test. Tubercle bacilli can not grow on LJ media containing 500 g/Liter PNB acid, and gives a positive niacin test. Regarding Nocardia, the inoculated sabouraud’s dextrose media were incubated at 27?C of 4 weeks, and examined for the growth started from fourth days for incubation, and negative cultures were discarded after four weeks of incubation. However, the findings of culture, and direct microscopical examination were negative. Regarding in immunological assays, two parameters were done in this study. a. Enumeration CD4 cells: The peripheral blood lymphocytes were separated by using Ficoll isopaque method, these cells were incubated with murine monoclonal antibodies to CD4 epitope (anti-CD4), then the processing of CD4 cells count was performed by using olympus fluorescence microscope. b. Determination IL-2: Cytokine enzyme immunoassay (EIA) was used for determination of IL-2 level from the sera of blood samples. The findings of this study revealed that: 1. Socioeconomic factors as illiterate, skilled and manual jobs represented the high percentage among tuberculous and healed tuberculous patients. 2. The majority of diagnosed TB cases were in the most productive age group (20-56 years). This means that the burden of tuberculosis falls heavily on the most economically productive sector of Egyptian’s, and Yemen’s societies.