Distribution of immunoglobulin heavy and light chain isotypes and IgG subclasses of multiple myeloma

Objective:To investigate the distribution of monoclonal immunoglobulin (M-protein) isotypes and IgG subclasses in patients with multiple myeloma (MM). Method:Immunofixation electrophoresis was used to detect immunoglobulin heavy and light chain isotypes in 236 patients with MM, and immunodiffusion electrophoresis was used to detect IgG subclasses in 76 patients with MM. Result:In the 236 MM patients, IgG paraprotein was detected in 104 ( 44.07 %) patients, IgA in 60( 25.42 %), IgD in 22 ( 9.32 %), and light chain paraprotein in 47 ( 19.92 %) patients, respectively. Nonsecrete isotpye MM in 3 ( 1.27 %) patients. All paraproteins were negative for IgE and IgM. IgG subclasses frequencies were 80.26 % IgG 1, 7.89 % IgG 2, 1.32 % IgG 1-IgG 2 biclone, 10.53 % IgG 3. No IgG 4 was detected. Conclusion:Detection of immunoglobulin heavy and light chain isotypes and IgG subclasses of multiple myeloma was very important in guiding therapy and prognostic determination.