[A case of IgA2-lambda type M-protein that IgA concentration differs from the values of M-protein by serum protein electrophoresis].
We report an IgA-lambda type M-protein in which the IgA concentration differed from the values of M-protein by serum protein electrophoresis found in a 53-year-old man with multiple myeloma. The M-protein value as determined by serum protein electrophoresis was 6,170 mg/dl. However, the serum IgA concentration was 3,052 mg/dl by turbidimetric immunoassay. Immuno-fixation electrophoresis using IgA subclass antisera revealed that this M-protein was the IgA2-lambda type. Western blotting analysis showed that the IgA2 molecules were composed of two approximately 68 kDa alpha 2 chains and two 28 kDa lambda chains. In addition the free lambda chain band was detected at the position of 28 kDa without 2-mercaptoethanol(2-ME) even though the patient IgA was purified. Since it is known that IgA2m(1) allotype easily release light chains from the IgA molecules in SDS-PAGE without 2-ME, we speculated that in this patient the IgA was the IgA2m(1) allotype. After peripheral blood stem cell transplantation(PBSCT), immunofixation electrophoresis of the patient serum revealed not only the bands of IgA2-lambda type M-protein, but also three bands of IgG1-kappa type M-protein in the gamma region.
Fukushima
M
M
Central Clinical Laboratory, Shinshu University Hospital, Matsumoto 390-8621.
Sugano
M
M
Ichikawa
T
T
Honda
T
T
Totsuka
M
M
Katsuyama
T
T
Fujita
K
K
D001797:Blood Protein Electrophoresis; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000150:complications / Q000628:therapy; D010265:Paraproteinemias / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D010266:Paraproteins / Q000032:analysis*
D007070:Immunoglobulin A; D007074:Immunoglobulin G; D010266:Paraproteins