Abstract
The concentrations of subclasses of IgG were determined in 28 normal human sera using the single radial agar diffusion method. The relative concentrations were 70.7±9.1% for IgGl, 24.1±10.4% for IgG 2, 3.5±1.3% for IgG 3, 2.8±1.7% for IgG4, respectively.
The IgG subclass distribution of 167 serum M-components derived from 134 myeloma, 12 suspected myeloma, and 21 benign or secondary monoclonal gammopathies was found to be 78.4% for IgGl, 13.8% for IgG 2, 5.4% for IgG3, and 2.4% for IgG4, respectively.
From above results, distribution frequency of IgG subclasses in Japanese was revealed to be very similar to the reported values in European as well as American literatures, except for the fact that the tendency of slightly lower percentage value of IgG3 in Japanese was found, but without statistical significance.
κ/λ ratios of subclasses of IgG M-components were as follows; 1.59 for total IgG, 1.73 for IgG1, 0.92 for IgG2, 0.8 for IgG3, respectively, and only kappa type was found for IgG4. Compared with the results in America and Europe, these results were in good accordance in amountrelationship between four subclasses, but differences were found in κ/λ ratio of each subclass, namely definitely lower for total IgG, Ig2, and IgG3; and seemingly lower for IgG1.
Therfore, low κ/λ ratio of IgG2 and IgG3 was considered mainly to contribute for characteristic low κ/λ ratio of IgG in Japanese.
To explore the influence of heredity on human IgG subclasses, serum concentrations were compared in 3 monozygotic twins and 5 dizygotictwins. Present results have not revealed any difference of similarity between morozygotic twins and dizygotic ones. It was felt further study using larger number of twin subjects was needed for the elucidation of this point.
