Pregnant women’s immune response to Flu goes up, not down

New research has found that influenza causes a surprisingly strong reaction in the usually more placid immune systems of pregnant women. The finding could lead to new treatments for pregnant women with sever influenza. Immunologically speaking, the developing foetus is a foreign object to a mother’s immune system.

So to prevent rejection of the foetus their immune systems are usually reigned in somewhat, even at the risk of being more open to infections. Flu seems to be particularly risky for pregnant women, and is more likely to lead to pneumonia and severe complications.

During the 2009 swine flu (H1N1) pandemic, infected pregnant women in Australia and New Zealand were 13 times more likely to be admitted to hospital with a serious illness than non-pregnant women. The researchers in this study took natural killer (NK) cells and T-cells – both important in fighting viral infections – from pregnant and non-pregnant women before and after a seasonal flu vaccination.
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Preaching Tolerance

INNATE-+-ADAPTIVESometimes, the immune system just backfires. It responds inappropriately, leading to autoimmune diseases like multiple sclerosis and systemic lupus erythematosus. Other times it overreacts to an otherwise harmless target, leading to allergies ranging from the mild, like hay fever, to the severe, like anaphylactic peanut allergies.

Autoimmune and allergic diseases are mostly a problem of the adaptive arm of the immune system, that part of immunity that can learn new targets and attack. But the ‘innate’, or non-specific, immune system plays its part too. Parts of it a necessary to help educate the adaptive arm, and to temper its responses. Exactly how is still not all that clear, but new research from Imperial College has shed a little more light on this process. Continue reading

Herpes on the brain could be a good thing?

herpes-on-the-brainWhat do these two odd pairings have in common? Cervical cancer and rabies vaccination. Hodgkin’s lymphoma and measles.

The answer is that they are both among the earliest case reports, as early as 1901, linking spontaneous remission of a cancer with a virus. These discoveries led to idea of using viruses to kill cancer cells, so-called ‘oncolytic viruses’.

It’s a neat idea. If you can get a virus to preferentially infect tumour cells, leaving normal cells and tissue alone, as it destroys the tumour cells more infectious virus is released to go on and infect the remaining tumour cells. In fact, it’s such a neat idea that there are currently a number of oncolytic viruses going through clinical trials right now.

But it’s not just through infection, replication and destruction of cells that a virus can kill a tumour. A virally infected cell can jump-start the immune system, bringing attention to tumour cells which had otherwise evaded the immune system, generating an anti-tumour immune response. Continue reading

Influenza A deploys counter measures to stymy host defences

flu-counterIn the evolutionary arms race there’s a constant battle between infectious diseases and their hosts defences. Now new research from the University of Texas has identified one of influenza A’s countermeasures, and it may one day prove to be its Achilles heel.

Influenza A viruses are one of the causes of seasonal flu problems throughout the world. We have good weapons against them: vaccines. But flu is a tricky character; mutating constantly, swapping genes with other flu strains in different animal hosts. This means by the time flu season returns, you may not be facing the same strain and are now unprotected.

Vaccines take time to design and prepare. The seasonal flu vaccine you last had was based on a best guess made by health agencies across the world. This guess was informed by a world-wide surveillance system, monitoring seasonal flu and new outbreaks.

When a new flu strain, like swine flu, suddenly appears and jets off across the world in its human hosts, there isn’t time to develop a vaccine. Antivirals become the first line defence against fast-moving flu pandemics. Currently only two classes of flu antivirals exist, aimed against either viral neuraminidase (like the much debated Tamiflu), or a viral ion channel protein called M2.

But there are clear signs that flu is becoming resistant to both of these approaches. Something new is needed to protect us against the next flu pandemic when it comes.

So where could we find it? Continue reading