Relevance of macro creatine kinase type 1 and type 2 isoenzymes to laboratory and clinical data.
From 8322 patients for whom creatine kinase (CK; EC 2.7.3.2) isoenzyme analysis was ordered, we identified 136 patients with macro CK isoenzyme in their serum. There were 36 cases with type 1 (prevalence: 0.43%) and 100 cases with type 2 isoenzyme (prevalence: 1.20%). About three-fourths of the patients were ambulatory at the time of testing, and approximately 90% of the first 68 patients identified survived at least 1 year after macro CK was found in their serum. Age and gender did not differ significantly between the two groups. The serum total CK was significantly higher (P < 0.0005), and an increased CK-MB proportion (> 0.05 of total CK) was also significantly more common (P < 0.0005) in patients with macro CK type 1 than in those with type 2. On average, macro CK type 2 accounted for approximately 25% and macro CK type 1 for approximately 10% of the serum total CK activity. Patients with macro CK type 1 most often had myositis, whereas those with macro CK type 2 most commonly had a malignancy. We conclude that the presence of macro CK isoenzymes has a low prognostic value for impending death, but may support the diagnosis of an autoimmune process (type 1) or malignant cell proliferation (type 2).
Lee
K N
KN
Clinical Pathology Department, W. G. Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892.
Csako
G
G
Bernhardt
P
P
Elin
R J
RJ
D000263:Adenylate Kinase / Q000737:chemistry; D000293:Adolescent; D000328:Adult; D000368:Aged; D000906:Antibodies / Q000494:pharmacology; D003402:Creatine Kinase / Q000037:antagonists & inhibitors / Q000097:blood* / Q000737:chemistry*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007527:Isoenzymes; D046911:Macromolecular Substances; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009220:Myositis / Q000201:enzymology; D009369:Neoplasms / Q000201:enzymology; D012016:Reference Values
D000906:Antibodies; D007527:Isoenzymes; D046911:Macromolecular Substances; D003402:Creatine Kinase; D000263:Adenylate Kinase