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SPARCC published the results of an investigation into the relationship between fatigue and psychosocial factors in psoriatic arthritis. Using a combination of questionnaires and laboratory tests, the research team discovered that fatigue is a common symptom amongst these patients. Fatigue has strong connections with pain, physical functional disability, and psychological distress. Dr. Dafna Gladman comments: “This is an important discovery which will aid physicians caring for patients with psoriatic arthritis, since fatigue has a major impact of the quality of life for these patients. Such studies are beginning to make a real difference for our patients.”

In 2005, 592 individuals in Ontario experienced food poisoning after consuming food products contaminated with Salmonella. SPARCC investigators found 53 individuals who developed arthritis after this episode of dysenteric outbreak. This provided important new information on the role of infection in the development of arthritis. The investigators then discovered that one particular gene (toll-like receptor 2) was associated with the type of arthritis that was developed. Dr. Robert Inman comments: “There has long been a suspicion about a role of infection as the cause of arthritis. With an outbreak of infection such as this, the opportunity arose to define what the interaction of genetics and infection might be which sets the stage of arthritis. This discovery has major implications for studying arthritis in populations exposed to common infectious diseases. It also suggests that new forms of treatment could be developed which are directed toward the interaction of the bacteria and this gene.

The effectiveness of methotrexate in the treatment of psoriatic arthritis has not been defined. A recent study from SPARCC sheds new light on this important question. Results showed there has been a recent trend towards methotrexate to be used earlier and at higher doses. Dr. Dafna Gladman comments: “This study ahs provided insights into changing practices in the treatment of psoriatic arthritis. More importantly, we have new evidence that methotrexate can lead to better clinical outcomes and can protect against damage to the joints.”

The genes which lie behind AS have been amongst the highest priorities of researchers studying this disease around the world. The study suggests ERAP1 may be play a significant role in AS disease. This represents the most significant genetic discovery in AS since HLA-B27 was discovered in 1973. It is particularly gratifying that this is a distinctively Canadian achievement, with patients drawn from across Canada. SPARCC researchers have made genetic studies a priority as this will greatly advance knowledge about the cause of AS and has important implications for earlier diagnosis and development of more effective treatments.

An important issue in caring for children with AS is the course of disease lying ahead for the patient. This is a common dilemma for parents as well as for physicians treating such patients. Dr. Inman comments: “This study has shed new light on the pattern of arthritis as these children grow up. This will be valuable for improving the care of these patients since it offers more information on what the long term course of the illness will be.”

With chronic forms of arthritis like AS, doctors have had great difficulties in being certain whether changes in symptoms reflected changes in the underlying disease. There are also difficulties in developing new tests which might help to guide the timing of treatment more accurately. Through looking at which genes are expressed with the disease is active, SPARCC discovered a protein in the blood called LIGHT that closely parallels disease activity. Dr Inman comments: “This is the kind of study which can directly impact patient care. This is a powerful new tool which will greatly assist physicians to determine how, and when to alter the treatment of patients.”

The arthritis which occurs in those with psoriasis has been recognized to be a serious form of joint disease which can lead to chronic pain and disability. A study by SPARCC has discovered that a gene associated with AS is also strongly associated with psoriatic arthritis. Dr. Photon Rahman comments: “This is a major advancement in psoriatic arthritis for two reasons. First, it provides an important new understanding of the mechanisms underlying the inflammation in the skin and the joints. Secondly, it suggests that treatments directed at this gene (IL-23 receptor) may be very effective in treating this form of arthritis. It is an example of genetic research which is directly applicable to improving the care of patients with psoriatic arthritis.”

In an international study of the genetics of AS involving 10 countries, SPARCC played a central role in defining the gene for Interleukin-1 as a risk factor for AS in different populations worldwide. Scientists genotyped nine variants in the Interleukin-1 gene cluster in AS cases and controls from 10 countries, and then tested association of variants with AS. Dr. Robert Inman comments: “International collaboration is critical to study genetics of such complex disorders as AS. Such collaborations can provide sufficiently large sample sizes to produce robust findings often not achieved in smaller studies. Canadian researchers are playing a critical role in this global network.”

An important relationship between AS, psoriasis, and inflammatory bowel disease was found. In a remarkable example of basic science clarifying clinical relationships, SPARCC has discovered that a single gene plays an important role as a risk factor for all three diseases. The gene encodes the receptor for a chemical mediator of inflammation called IL-23. The SPARCC team examined cohorts of AS patients from rheumatic disease centers across Canada, making this a distinctively Canadian discovery. Dr. Photon Rahman comments: “This opens the door for earlier diagnosis of these conditions since measuring levels of interleukin-23 might reveal provide clues to inflammation in the joints, bowel and skin. Also, it suggests that new treatments which target interleukin-23 might be effective in all three diseases. This is an example of a discovery in genetics which opens the door to new therapies.”

In a major study of patients with psoriatic arthritis, SPARCC has discovered cardiovascular disease occurs with greater frequency in this patient than in the general public. Dr. Dafna Gladman comments: “Physicians now have to be alert to other modifiable factors which might contribute increased risk of heart disease. It also suggests that the importance of controlling arthritis in these patient lies not only in improving the symptoms of joint disease, but that there may be important secondary benefits such as reducing the risk of heart disease. We now know that both are important reasons for timely diagnosis and effective treatment for patients with arthritis. These have been the guiding principles of SPARCC.”