Evidence is mounting suggesting that multiple sclerosis (MS) is a T-cell-mediated autoimmune disease similar to rheumatoid arthritis (RA), with genetic and environmental factors playing a role in their pathogenesis. Reporting in the May 2006 issue of the Journal of Rheumatology, researchers identify an association between the two conditions “Since a great proportion of our patients developed MS first and subsequently RA, the best explanation for these cases is a predisposition in MS patients to develop another autoimmune disease with common etiologic cofactors,” comment the investigators, led by Dr Eric Toussirot (University Hospital Besancon, France).
“In our series, MS did not seem to have an influence on the clinical course of arthritis, and vice versa,” they explain. “The concurrence of MS in our patients did not prevent joint damage in most cases and thus – despite the neurologic disease – RA will probably continue to progress.”But given the potential for neurological adverse events with anti-TNF therapy, the researchers caution clinicians about these drugs. “We recommended the careful evaluation of patients with RA before anti-TNF- administration and the avoidance of this treatment in those with preexisting MS diagnosis, a history of unexplained central neurologic signs, or a family history of MS.”Risk of neurological adverse events with anti-TNF therapy In a separate paper, also published in the Journal of Rheumatology, another group of investigators highlight the potential risk of anti-TNF therapy . The team, led by Dr Julie Jarand (University of Calgary, AB), describes three patients who developed neurological disease associated with the use of infliximab, a monoclonal antibody that binds to and inactivates TNF. “All had evidence of polyneuropathy, demyelinating in one and axonal in two,” they note. “One patient had a central nervous system syndrome.” The researchers emphasize that physicians should be aware of these potential adverse effects when treating patients with infliximab.Toussirot and his team point out that MS is the most frequent demyelinating disease and has been associated with various chronic inflammatory diseases. In their retrospective study, the investigators evaluate the association between MS and RA.Physicians from the Club Rhumatismes et Inflammation, a subgroup of the French society of rheumatology, were asked to report cases of MS and RA occurring in the same patient. A rheumatologist was required for the diagnosis of RA and a neurologist for the diagnosis of MS. They identified 14 patients, which included 12 men and two women. RA was diagnosed before MS in three cases while MS preceded RA in 10 cases. The diseases were identified simultaneously in one case.The researchers excluded patients on previous anti-TNF therapy. They analyzed age at RA and MS onset, extra-articular disease, joint-space narrowing, and erosions on hand or foot radiographs, rheumatoid factors, antinuclear antibodies, treatments for RA, disease course of MS, neurologic symptoms, brain and spinal-cord magnetic resonance imaging findings, cerebrospinal-fluid analysis, visual evoked potential results, and MS treatments, as well as patient outcome.Toussirot and colleagues observed radiographic erosions in 11 cases and joint-space narrowing in nine cases. Rheumatoid factor was positive in six cases and antinuclear antibodies were found in only four cases. The treatments they received were mainly methotrexate, and other disease-modifying antirheumatic drugs were rarely used. Most patients received corticosteroids for their arthritis. Treatments for MS were mainly intravenous methylprednisolone, immunosuppressive drugs, and interferon.The investigators found that MS usually occurred between 20 and 40 years of age, while the onset of RA was generally between the fourth and sixth decade. They conclude, “Autoimmunity in MS is well demonstrated, and it is reasonable to consider that patients with MS are prone to develop other autoimmune diseases.” (Sources: Joint and Bone: Rheumawire: May 2006:1) Toussirot E, Pertuiset E, Martin A, et al. Association of rheumatoid arthritis with multiple sclerosis: Report of 14 cases and discussion of its significance. J Rheumatol 2006; 33:1027-1028. 2) Jarand J, Zochodne DW, Martin LO, et al. Neurological complications of infliximab. J Rheumatol 2006; 33:1018-1020.)