MCTD – Mixed Connective Tissue Disease

Abstract

Mixed connective tissue disease is a disease entity characterized by overlapping symptoms of lupus erythematosus (LE), systemic sclerosis (SSc), polymyositis/dermatomyositis (PM/DM) and rheumatoid arthritis (RA). Diagnostic criteria include high titers of antibodies against U1RNP as well as the presence of at least 3 of 5 of the following clinical features: edema of hands, synovitis, myositis, Raynaud phenomenon and acroscierosis. In terms of the pathogenesis, genetic as well as infectious (viral) factors appear to play a role. The acceptance of MCTD as a distinct disease entity is controversial. Terms such as "undifferentiated connective tissue disease" or "overlapping syndromes" are not helpful. One-quarter of MCTD patients transform into LE, while one-third progress to SSc. Therapeutic recommendations are glucocorticoids in combination with immunosuppressive agents and endothelin receptor antagonists. Double blind studies are not available. The prognosis is relatively good. Causes of death include pulmonary hypertension, infections and both pulmonary and cardiac failure.

Can SLE classification rules be effectively applied to diagnose unclear SLE cases?

“…As previously reported (Luyckx et al, 2005; Ball et al, 2007; Kumar et al, 2009), elevated levels of anti-dsDNA, anti-Sm, red blood cell casts, thrombocytopenia, non-erosive arthritis as well as pleuritic and/or pericarditis are present in clear SLE cases. By contrast, unclear patients exhibit elevated frequencies of synovitis and tenderness in two or more joints, pericarditis and leukopenia ( p ≤ 0.01) as has been previously reported (Haustein, 2005). The proposed reduced models from currently used classification criteria sets highlight clinical and molecular features that help unclear SLE and MCTD segregation ( Table 3 ).…”