Abstract:

Objective To study the laboratory determination characteristic of 95 patients with monoclonal gammopathy of undetermined significance（MGUS）. Methods Totally,95 patients with MGUS were enrolled. The age and sex were recorded,and the amount and subtype of monoclonal protein were determined.Results The monoclonal immunoglobulin was IgG in 63 cases,IgA in 22 cases,IgM in 8 cases,biclonal in 1 case and light chain in 1 case. The amounts of monoclonal protein were 5.2（2.6~8.6）g/L in IgG MGUS,4.9（3.2~8.6）g/L in IgA MGUS and 5.1（4.2~6.9）g/L in IgM MGUS,respectively. The κ/λ ratios were 2.2（0.7~4.2） in IgG MGUS,1.7（1.1~3.0） in IgA MGUS and 1.6（0.9~3.4） in IgM MGUS,respectively. The average amount of monoclonal protein was 6.3 g/L in 95 patients,and 7 cases had a concentration of ≥15 g/L. There was no statistical significance in patients' age,sex,monoclonal protein amount and κ/λ ratios in each subtype（P>0.05）. Two cases（1 case of light chain type and 1 case of IgG λ） transformed into multiple myeloma（MM）,and one case transformed into smoldering myeloma（IgG κ） and one case transformed into smoldering Waldenström macroglobulinemia（IgM κ）,respectively,in 1 year. Conclusions IgG MGUS is the most common subtype,followed by IgA MGUS. It should pay attention to identify high-risk populations of MGUS and standardize their follow-up to make them be diagnosed and treated in the early stage of disease progression.

Key words: Monoclonal protein, Classification, Monoclonal gammopathy of undetermined significance