Health – Autoimmune issues on the rise

Recently I was working in a part of the South Island that seems to have a high prevalence of autoimmune disease (AD). I can honestly say that I have never seen so many cases of psoriasis, rheumatoid arthritis, Grave’s disease (thyroid overactivity) and related conditions.

A literature search gave no explanation, reflecting the general uncertainty about the cause of these illnesses. 

AD occurs when the body’s immune system malfunctions and starts attacking its own cells. Practically any organ system can be affected and there are scores of different maladies caused by this unfortunate “friendly fire”. Moreover, the incidence is increasing worldwide. There has been speculation that contributing factors are diet, air pollution, stress, lifestyle factors, climate change, chemicals and viruses, but nobody really knows. Likewise, the higher incidence in women is mysterious.

Vaccines can cause ADs but fortunately such reactions appear to be rare. However, longer term studies are required and a swathe of new vaccines need to be evaluated. 

There is a definitely a genetic susceptibility and a tendency for ADs to come in clusters, so it is not unusual for a patient to have some combination of, for example, coeliac, thyroid and Type 1 diabetes, all at once. 

Invertebrates, which have a much more basic immune system, don’t get AD, suggesting that a tendency to misfire is part of the price we pay for having highly developed immune responses. The rogue cells that attack our own tissues are usually mopped up in the thymus or the peripheral blood, but clearly that quality control mechanism is not perfect. 

But to the person with an AD, this is all rather academic. Most ADs have no cure, and patients can face a lifetime of debilitating symptoms.

Historically, all we had to offer them were blunderbuss immune suppressants like prednisone. While this gave significant relief, the long-term side effects were a major drawback – sometimes the treatment was worse than the disease. Disease-modifying antirheumatic drugs (DMARDs), such as methotrexate, were a significant step forward, as they could be targeted to specific conditions and helped to prevent progressive joint damage. But they still required specialist expertise and close monitoring for adverse effects. 

The real breakthrough came with the development of monoclonal antibody drugs. These can be chemically engineered to target practically any protein and so have broad application as immune suppressants, anti-cancer drugs, diagnostic agents, antivirals and even treatment of osteoporosis, migraine and macular degeneration.

As these drugs can be customised to any situation, there is literally no end to their potential. However, they have almost unpronounceable names – have a crack at bevacizumab, for instance. But, in short, if it ends in “mab”, it’s a monoclonal antibody. 

And cost is a factor, sometimes running into tens of thousands of dollars for a course. This means that in New Zealand these drugs have to be approved by a specialist and are subsidised only for the more severe cases or situations where therapeutic benefit is most likely. How to make the most cost-effective use of these agents is a matter of ongoing debate.