Activities of creatine kinase and its isoenzymes in serum in various skeletal muscle disorders.

We studied possible correlations between anatomopathological and clinical features and the values for total creatine kinase (CK; EC 2.7.3.2) and its isoenzymes, including the proportion of CK-MB, in a population displaying several neuromuscular pathologies. Although we observed no specific isoenzyme pattern associated with the different myopathies, we found isoenzyme analysis useful in studying the histopathological evolution of illness. We also considered whether the pathology was regenerative or nonregenerative, and what type of fiber (I or II) was involved. High CK-MB percentages (greater than 6%) were associated with regenerative and type I fiber myopathies, with regenerative type tissues being the principal factor associated with an increasing proportion of CK-MB. Studying the changes in CK-MB percentage in serum appears to be useful in discriminating neuromuscular from myocardial pathologies.