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. CKMB was elevated in 51%, cTnT in 41%, and cTnI in only 2.5% of patients. cTnI did not correlate with other markers or with disease severity scores. The close correlations found between cTnT and skeletal muscle damage markers and the relationship between cTnT with disease severity without clinical evidence for myocardial damage suggest a release of cTnT from skeletal muscle. The relationship of cTnT with disease severity indicates a possible role of the marker for risk stratification. However, the prognostic values of cardiac troponins and other muscle damage markers in PM/DM patients remain to be compared in prospective outcome trials.

[Serum neopterin in hemorrhagic vasculitis]

Out of 12 patients with hemorrhagic vasculitis (HV) having the disease for 3-3.2 years (5 males and 7 females aged 18-55 years, mean age 34 +/- 13.8 years) renal affection was found in 3 (25%) patients. Renal function was normal in all the patients. One patient had nephrotic and two had mixed nephritis. One patient had gastrointestinal lesions. Serum neopterin was measured by radioimmunoassay. Mean concentration of serum neopterin was significantly higher than in donors (9.15 +/- 6.82 nmol/l and 5.2 +/- 2.1 nmol/l, respectively). A high neopterin level was found in 2 (67%) of 3 patients with nephritis and in 1(11%) of 9 patients free of nephritis. Mean neopterin was significantly higher in 3 patients with renal disorders than in the comparison group. A positive correlation existed between neopterin level and the clinical activity index, ESR, IgA, IgG CIC concentrations.