I have just registered and completed a fantastic educational initiative on Tuberculosis (TB) -- TB Learning Zone - produced by Oxford Immunotec. Registration is free and it takes about 90 minutes to complete the training in the Learning Zone.

After completion of the training the user gains access to a great PowerPoint presentation filled with high quality images. A very useful tool for students of pathology, infectious diseases and practicing clinicians alike.

The pathophysiology and immunological detection of latent disease including the use of interferon gamma release assays (IGRAs) are highlighted. The World Health Organisation has recently emphasized the importance of identifying and treating latently infected subjects in their statement:

Tuberculosis control and elimination strategies must aim at diminishing the incidence and prevalence of latent infection to reduce the pool of those with tuberculosis infection from which future cases of tuberculosis will emanate

Topics included in the intereactive learning experience include

• Epidemiology and risk groups
  • Tuberculosis (TB) is the clinical consequences that can be attributed to an infection by the organism Mycobacterium tuberculosis (MTB).
• Latent TB Infection (LTBI) -- interactive flash video
  • Latent TB infection is a subclinical infection with MTB, without clinical, bacteriological or radiological signs or symptoms of active TB disease.
• Basic microbiology
  • Mycobacterium tuberculosis (MTB) is a pathogenic mycobacterium. It is an intracellular pathogen which thrives in highly aerobic environments such as the human lung
• Pathogenesis
  • Infection with MTB most likely occurs when bacteria are inhaled from a cough droplet and reach the terminal bronchi where they are phagocytosed by alveolar macrophages. Alveolar macrophages are mobile, immune surveillance cells, and are the predominant luminal airway phagocyte.
• Memory T Cells in MTB -- interactive flash video
  • The primary immune response involves presentation of MTB antigen to naïve T helper lymphocytes
• BCG, Genomic Deletions and RD1 Antigens -- interactive flash video
  • The Bacillus Calmette-Guerin (BCG) vaccine was produced by culturing the virulent Mycobacterium bovis until it was attenuated through the deletion of several regions of genetic coding (regions of difference -- RDs). The first of these regions to be deleted is known as the RD1 region.
• Clinical Patterns of Disease
  • Most patients with MTB infection have latent disease (LTBI) and are asymptomatic.
• TB Diagnostic Methods
  • IGRAs -- interactive flash video
  • Commercial IGRAs are in vitro tests which can be used in place of, or along side the Tuberculin Skin Test (TST).  They are more specific than the TST as they do not cross react with BCG or most environmental mycobacteria. The T-SPOT.TB assay is more sensitive than the TST [Reference]

• Treatment of TB infection
  • Patients who are suspected of having active TB disease may be given a number of different tests to confirm the damage caused by the infection or to identify the organisms responsible for the infection.

MTB Primary Infection

a. T Cell Responses

b. T Cell Responses

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