Thirty-one multiple myeloma patients were classified chiefly by heavy and light chain detec- tion of myeloma protein （M protein）.The results were as follows:19 out of the 31 cases belonged to the IgG class

including the following subclasses—IgG1-λ.7;IgG1-k.5; IgG3-λ

1;IgG3-k

2;double M myeoma

2 （IgG3-λ+IgG2-k

IgG1-λ+IgG4-λ）;IgG-λ

1;and IgG1-k 1.Seven cases were light chain diseases

of which 4 belonged to λ type.2 were k. and one was a double light chain disease.Five cases belonged to the IgA class （IgA-λ

3; IgA-k

2）.We found no correlation between electrophoretic mobility and the antigenicity of M protein even within subclasses

and the highly concentrated BJP in urine had a tendency to form light chain polymers

possibly along different polymerization pathways.