Monoclonal cryoglobulins and pyroglobulins.

In a series of 1182 monoclonal Ig, the authors demonstrated 10 cases with monoclonal cryoglobulin (0.8%) and 5 cases with pyroglobulin (0.42%) in the serum; in two of these cases both thermoproteins were present simultaneously. One observation revealed mixed cryoglobulin consisting of monoclonal IgM-kappa and polyclonal IgG. In 70 Waldenström's macroglobulinemias, monoclonal cryoglobulin occurred in 10%, pyroglobulin in 5.71%. In a subgroup of 744 monoclonal IgG, monoclonal cryoglobulin was demonstrated in 3 cases (0.4%), pyroglobulin in one case (0.13%).