Cardiac troponin and beta-type myosin heavy chain concentrations in patients with polymyositis or dermatomyositis.

Cardiac troponin T (cTnT), cardiac troponin I (cTnI), myosin heavy chains (MHC), myoglobin, creatine kinase (CK), and creatine kinase isoenzyme MB (CKMB), were measured in blood samples from 39 polymyositis (PM) or dermatomyositis (DM) patients without clinical evidence for cardiac involvement to evaluate their clinical usefulness in this patient population. MHC, myoglobin, and CKMB were frequently elevated and correlated with each other and with disease severity. Undetectable cTnI in all but one patient indicated that MHC was released from skeletal muscle, thereby providing the first laboratory evidence of frequent slow-twitch muscle fibre-necrosis in patients with PM or DM.

Anti-endothelial cell antibody, thrombomodulin, and von Willebrand factor in idiopathic inflammatory myopathies.

Sera from 19 patients with idiopathic inflammatory myopathy (IIM) were examined for the presence of anti-endothelial cell antibodies (AECA) by an immunoglobulin G-specific cellular enzyme-linked immunosorbent assay. The mean binding index of AECA was found to be 37.7% +/- 26.

Elevated serum levels of neopterin in adult patients with polymyositis/dermatomyositis.

We determined serum concentrations of neopterin, soluble tumour necrosis factor (55 kDa) receptor (sTNF-R) and soluble interleukin-2 receptor (sIL-2R) in plasma of 44 patients with polymyositis (PM)/dermatomyositis (DM), including 15 patients with primary PM, 13 patients with primary DM, and 16 patients with myositis and systemic sclerosis in overlap. Concentrations of neopterin, sTNF-R and sIL-2R were measured using commercially available immunoassays. Serum neopterin was increased in 35 of 44 PM/DM patients (80%), sTNF-R in 14 (32%) and sIL-2R in 18 (41%) patients, respectively.