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Tag: pneumonia

How a Unique Type of T-cell Can Protect Against Pneumonia

We’ve all probably heard of pneumonia, or even know someone who has had it. Pneumonia is a lung infection that can be caused by bacteria, viruses, or fungi. This infection causes the lungs’ air sacs to fill with fluid, making it hard to breathe. The majority of cases of community acquired pneumonia are linked to Streptococcus pneumoniae (the pneumococcus). Because there is a significant chance of developing bloodstream infection in these cases, the fatality rate is high. Even with antibiotic treatments and vaccines, the fatality rate is 20% for young adults and 60% for the elderly. Although the reason why some individuals are more susceptible to this disease and why others are not has been a mystery for decades, scientists have discovered a cell that may provide some answers.

At the University of Liverpool, the Bacterial Pathogenesis and Immunity Group has identified a subset of white blood cells in mice known as TNFR2 expressing regulatory T cells (Tregs).

In class, we learned that T cells were involved in the cell-mediated response of adaptive immunity. During the immune response, T-helper cells are activated by interleukin to recognize the antigen and trigger the cell-mediated and humoral responses. T-memory cells are created to confer future immunity while T-killer cells are created to kill infected or cancerous cells. A subset of T-cells called regulatory T cells also regulate the immune system. During pneumonia infection specifically, these cells are involved in bacteraemic pneumonia resistance through maintaining and controlling frontline immune responses during infection in the lungs. T Regulatory Cells

When these cells are not functioning correctly or are missing, there is excessive and uncontrolled inflammation that results in tissue damage. This allows the bacteria to enter the bloodstream through the disrupted lung tissue barrier and cause sepsis, which is the body’s life-threatening response to infection.

Professor Aras Kadioglu, the leader of the Bacterial Pathogenesis and Immunity Group, stated, “This is a significant finding, which opens the door to potential new therapies which may target and modulate these subset of Tregs to prevent and treat severe invasive pneumococcal diseases.”

This article caught my attention because I have never heard of this subset of T cells before. Given how severe pneumonia is, it will be interesting to see how scientists will use this information to create new life-saving treatments.

CAP v.s. HAP: Pneumonia in the Microbiome

While many may not know this, there are various types of pneumonia.  The most common variant, CAP (community-acquired pneumonia), is the most prevalent strain of the infectious disease.  As the name may suggest, CAP is acquired through daily interactions (whether that may be contact or inhalation of pathogens which could later travel to the lungs) with any surface that has bacteria such as Streptococcus pneumoniae and Haemophilus influenzae.

While pneumonia is a well-known infectious disease among the population in 2019 due to the plethora of literature and research done on it, most people do not know that other variants of pneumonia are contracted in different ways, through different strands of bacteria.  HAP (hospital-acquired pneumonia or healthcare-associated pneumonia) can be contracted from extended periods of time in a hospital, nursing home, or rehabilitation center.  This pneumonia variant is a result of the P. aeruginosa and Staphylococcus aureus bacteria, which are completely different from the bacteria that cause CAP.

The demographics of people who suffer from each of these variants appear to be mostly similar with the only difference being that CAP has a stronger association with COPD whereas HAP still has an association with COPD, but in a smaller portion of the demographic.  Similarities between the two are the increased risk if one uses tobacco products or suffers from COPD, however, aside from these shared risk factors, the two variants are different in treatment methods (effectiveness of certain antibiotics) and contraction.

Relative to the microbiome, the major differences in the diseases can be found when testing biomarkers.  According to Ann Transl and Thomas Tschernig of the “Annals of Translational Medicine”, “lower levels in HAP as compared to CAP were found for MMP-8 and soluble E-selection, higher levels in HAP as compared to CAP were found for protein C”.

The significance of this discovery lies in the fact that the different variants of pneumonia could not be prevented, diagnosed, or treated in the same ways, thus exemplifying the dangers that would arise if the different variants were not classified and identified.

Additional resources.



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