The cause of lupus is unknown. However, research efforts over the past 30 years have led to a much better understanding of the disease. The current thinking is that SLE is clearly a multifactorial illness (many factors are involved). It is also clear that practically every aspect of the immune system has been reported to be abnormal. However, it is still not clear what triggers these abnormalities.
One hallmark of these abnormalities is that many autoantibodies are produced such as anti-DNA and anti-Sm. Why these particular antibodies are only found in lupus patients is not known but it is likely that they are somehow related to the cause of the disease. Autoantibodies are clearly responsible for at least some of the symptoms such as hemolytic anemia or kidney involvement. This knowledge justifies the use of prednisone and other treatments that decrease the production of antibodies. Several Canadian researchers are studying the characteristics of these antibodies, the molecules to which they bind (these are called antigens) and their relationship to SLE.
It is suspected that a virus may be the cause of lupus but there is not enough evidence to support this theory and, to date, no likely virus has been found. This theory is now being examined using the powerful tools of molecular biology, looking for traces of virus material in the cells of lupus patients.
The influence of heredity is also being studied in lupus. I mentioned in the opening chapter that there is a higher risk of developing lupus in relatives of lupus patients. The risk is still less than 5% but that is greater than the risk to the general population. By studying the relatives of lupus patients, it may be possible to identify a factor which predisposes a person (increases the risk) to develop lupus.
Hormones are clearly a factor, as is obvious from the disease’s fondness for women of child-bearing age. Other evidence is provided by flares of lupus that occur at times of hormonal change such as during pregnancy and while taking birth control pills. In lupus research, it has been found that certain strains of mice develop a form of lupus where there is a marked difference in the development and severity of lupus, depending on whether the mice are female or male. These mice provide valuable models for studies on how hormones and heredity influence the development of lupus.
Canadians have also contributed greatly to lupus research in areas such as the development of better tests for diagnosing lupus and the pioneering of a treatment called plasma exchange. In this treatment, the blood of seriously ill patients is filtered to remove complexes of antibodies. In the space of this short section, it is unfortunately not possible to mention all the efforts of those researchers in Canada dedicated to the study of lupus.
In addition to the research conducted in laboratories, a new form of research is being developed that studies lupus by looking at its thousand faces. In many centers in Canada, information on patients is gathered at each visit and entered into a computer program. By studying these pieces of information, gathered from a large number of people, it becomes possible to make some sense of the disease’s apparent complexity. For instance, it is now becoming possible to classify SLE patients with similar symptoms into groups called subsets. In turn, the study of particular subsets gives clues as to possible causes and helps to improve the diagnosis and treatment of lupus.
Finally, one of the great strengths of Canadian lupus research is that it is carried out by, or in co-operation with, the physicians who provide care to lupus patients in University Hospital Lupus Clinics. This setting speeds up discoveries and their use in lupus patients’ care. Because the results of all research are shared, patients who take part in these studies have the satisfaction of knowing that they are making a contribution to the well-being of lupus patients everywhere.