Systemic sclerosis, also known as scleroderma, is a rare autoimmune connective tissue disorder that’s difficult to treat. However, thanks to new research at Northwestern University Feinberg School of Medicine and Dartmouth’s Geisel School of Medicine, doctors may be able to treat some patients more effectively.
Characterized by thickening of the skin, scleroderma can also cause significant complications in the joints and internal organs - particularly the esophagus, lower gastrointestinal tract, lungs, heart and kidneys. There is no cure - and the one drug commonly used to treat the disease, mycophenolate mofetile (MMF) does not work for all patients. In the absence of a biomarker to inform therapeutic medical decisions, patients are exposed to ineffective and potentially toxic medications.
In the first study of its kind in scleroderma, Monique Hinchcliff, M.D., assistant professor of medicine at the Feinberg School, associate director of the Northwestern Scleroderma Program, and a physician at Northwestern Memorial Hospital, and Michael Whitfield, associate professor of genetics at the Geisel School of Medicine, together have shown that gene expression signatures can accurately identify patients who will positively respond to a particular therapy.
The paper was recently published electronically in the Journal of Investigative Dermatology.
“There is the potential for adverse reactions including death with scleroderma therapies, and delay in initiating appropriate therapy can be harmful,” Hinchcliff said. “Selecting effective treatment for each patient is the major issue facing physicians treating scleroderma patients.”
Whitfield’s and Hinchcliff’s findings revealed that patients whose conditions improve with MMF therapy all share a particular gene expression pattern in skin.
During the clinical trial, patients who improved during MMF therapy were classified in the inflammatory gene expression subset, while patients who did not improve were classified in the normal-like or fibroproliferative gene expression subsets. This fits the initial hypothesis since MMF impairs lymphocyte proliferation.
Systemic sclerosis or systemic scleroderma is an autoimmune or connective tissue disease. It is characterized by thickening of the skin caused by accumulation of collagen, and by injuries to the smallest arteries. There are two overlapping forms. Limited cutaneous scleroderma is limited to the skin on the face, hands and feet. Diffuse cutaneous scleroderma covers more of the skin, and is at risk of progressing to the visceral organs, including the kidneys, heart, lungs and gastrointestinal tract are affected.
Survival is determined by the severity of visceral disease. Prognosis is difficult to predict until the disease differentiates into recognizable subsets. Patients with limited cutaneous scleroderma have a good prognosis, with 10-year survival of 75%, although <10% develop pulmonary arterial hypertension after 10 to 20 years. Patients with diffuse cutaneous scleroderma have a 10-year survival of 55%. Death is most often from pulmonary, heart and kidney involvement, although survival has greatly improved with effective treatment for kidney failure. Immunosuppressive drugs are used, although glucocorticoids have limited application.
Annual incidence is 19 per million, and prevalence is 19-75 per 100,000, with a female:male ratio of 3:1, and 8:1 in mid to late childbearing years. Incidence is twice as high among African Americans, and the Choctow Native Americans in Oklahoma have the highest prevalence in the world (469/100,000). There is some hereditary association, some suggestion of immune reaction (molecular mimicry) to a virus, and some cases caused by toxins.[
An MMF response gene expression signature was also identified—the signature was composed of genes whose expression changed significantly during MMF treatment in patients that improved, but was absent in patients that did not improve.
The results of these experiments suggest that analysis of gene expression in skin may allow targeted treatment in patients with scleroderma.
While this is a small pilot study, it represents an important step forward in approaching complex rare diseases, such as scleroderma, where existing therapies show little or no efficacy, notes John Varga, M.D., the John and Nancy Hughes Professor at the Feinberg School and a physician at Northwestern Memorial, who also participated in the study.
If validated in a larger patient cohort now underway, the results will have significant impact on the development of effective treatment strategies for patients with systemic sclerosis.
###
The research paper is titled, “Molecular Signatures in Skin Associated with Clinical Improvement During Mycophenolate Treatment in Systemic Sclerosis.”
This work was supported in part by grants K12 HD055884 from the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health, grants U01 AR055063 and R25CA134286 from the National Cancer Institute from the National Institutes of Health, grants P60 AR48098 and P50AR060780 from the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health and by the Arthritis Foundation, the Scleroderma Foundation and the Scleroderma Research Foundation.
###
Marla Paul
.(JavaScript must be enabled to view this email address)
312-503-8928
Northwestern University
Provided by ArmMed Media
