Tomaszewski J, Kowalewski J
Clin Chim Acta. 1975 Apr 16;60(2):185-9. doi: 10.1016/0009-8981(75)90123-0.
The content of the high-molecular-weight protein-bound hydroxyproline (Hyp) and IgM level in the sera of 30 healthy persons and 29 patients showing changes in gamma and/or beta globulin levels was determined. Statistically significant correlations between quantities of these components have been found. On the base of the present results as well as the results of previous studies authors suggest that the high-molecular-weight Hyp-protein contains immunoglobulin of the IgM class.