Autoimmune diseases–which involve an abnormal immune system response against compounds and tissues normally located in the human body–seem to be more prevalent among females. For instance, while autoimmune diseases affect just 8 percent of the human population, 78 percent of those infected are women, according to a paper published in the journal Emerging Infectious Diseases in November 2004.

The only medical conditions that are more common throughout the United States than autoimmune diseases are cancer and heart disease. As many as 22 million Americans may be affected by autoimmunity right now. Some typical disorders associated with autoimmunity include rheumatoid arthritis, myocarditis, and multiple sclerosis.

A portion of proof points at previous infections for the link between women and autoimmunity. In fact, animal model studies have illustrated that infections can produce autoimmune diseases. Essentially, gender-based hormones may push forward a hyper immune response to infection in certain persons, which may bring forth a higher percentage of the condition among females.

Researchers have uncovered in the past that autoimmunity is caused by both genetic and environmental factors. Certain strains of mice, for instance, have developed these particular conditions without any clear infections. Nonetheless, a wealth of information has also associated diabetes, myocarditis, multiple sclerosis, and other autoimmune diseases with prior infections.

Some of the reasoning behind why the immune system may overreact to a body’s own tissues is due to the antigens of an infectious microorganism mimicking and resembling self-antigens. After a microbe causes an immune response, the likelihood of a cross-reaction with self-antigens rises. Researchers have also found that adjuvants administered in animal models stimulate the immune response in a similar way as when given a self-antigen. This causes organ-specific autoimmunity.

Based on studies of monozygotic, identical twins, genetics accounts for at least 30 percent of autoimmune diseases. Genes involving apoptosis, which is a typical way for immune responses to be shut down, have been associated with autoimmunity.

The investigators wrote that they established a mouse model with myocarditis or inflamed cardiac tissue to study the connection between infection and autoimmune disease. The animal model was infected with CB3, which has been implicated in heart failure.

The researchers used genetic analysis to find that myocarditis is linked to genes on the mouse chromosomes 1 and 6. The study also shows that heart inflammation began approximmimately seven to twelve days after onset of infection in the mice. The investigators discovered that two different viruses may also be implicated in myocarditis.

Much of scientific knowledge on the variances between male and female autoimmune responses stems from these type of animal models. Women seem to have a stronger immune response and produce more antibodies. The sex hormone testosterone, estrogen, and progesterone may be the main reasons for the differences found between each gender’s immune response. Once again, animal models have proven to be effective in uncovering some key facts about serious medical conditions.

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Categories: Allergy and auto-immunity

Tags: animal model studies, arthritis, autoimmunity, immune system, multiple sclerosis, myocarditis