Cytokine Storm - The Real Killer!

NEWS FLASH!  Flu actually convinces your body to kill itself!

A cytokine storm, or hypercytokinemia is a potentially fatal immune reaction consisting of a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines.

The primary symptoms of a cytokine storm are high fever, swelling and redness, extreme fatigue, and nausea.

When the immune system is fighting pathogens, cytokines signal immune cells such as T-cells and macrophages to travel to the site of infection. In addition, cytokines activate those cells, stimulating them to produce more cytokines. Normally, this feedback loop is kept in check by the body. However, in some instances, the reaction becomes uncontrolled, and too many immune cells are activated in a single place. The precise reason for this is not entirely understood but may be caused by an exaggerated response when the immune system encounters a new and highly pathogenic invader. Cytokine storms have potential to do significant damage to body tissues and organs. If a cytokine storm occurs in the lungs, for example, fluids and immune cells such as macrophages may accumulate and eventually block off the airways, potentially resulting in death.

The cytokine storm (hypercytokinemia) is the systemic expression of a healthy and vigorous immune system resulting in the release of more than 150 inflammatory mediators (cytokines, oxygen free radicals, and coagulation factors). Both pro-inflammatory cytokines (such as Tumor necrosis factor-alpha, Interleukin-1, and Interleukin-6) and anti-inflammatory cytokines (such as interleukin 10 and interleukin 1 receptor antagonist) are elevated in the serum of patients experiencing a cytokine storm.

It is believed that cytokine storms were responsible for many of the deaths during the 1918 influenza pandemic, which killed a disproportionate number of young adults with very healthy immune systems. In this case, a healthy immune system may have been a liability rather than an asset.

Preliminary research results from Hong Kong also indicated this as the probable reason for many deaths during the SARS epidemic in 2003.

Human deaths from the bird flu H5N1 usually involve cytokine storms as well.

Recent reports of high mortality among healthy young adults in the 2009 swine flu outbreak has led to speculation that cytokine storms could be responsible for these deaths. However, the Centers for Disease Control and Prevention (CDC) has indicated that symptoms reported from this strain so far are similar to those of normal seasonal flu, with the CDC stating that there is "insufficient information to date about clinical complications of this variant of swine-origin influenza A (H1N1) virus infection."

A 2003 report in the Journal of Experimental Medicine published by researchers at Imperial College London demonstrates the possibility of preventing a cytokine storm by inhibiting or disabling T-cell response. A few days after T cells are activated, they produce a biologic molecule called OX40, a "survival signal" that keeps activated T-cells working at the site of inflammation during infection with influenza or other pathogens. OX40 binds to receptors on T-cells, preventing them from dying and subsequently increasing cytokine production.

By blocking the OX40 receptor on T-cells, researchers were able to prevent the development of the most serious flu symptoms in experimental mice and reported the results in New Scientist. The drug to block OX40, to be made by a company called Xenova Research (Xenova Research was purchased by Celtic Pharma, a private equity firm, in September 2005), was supposed to be in phase I clinical trial in 2004, but its status is currently unknown.  However, if perfected could be the magic bullet to minimize the effects of one of the most lethal virus the world has seen!