Correlation between serum levels of free light chain and phenotype of plasma cells in bone marrow in primary AL amyloidosis.
To investigate whether there is a correlation between subtypes of plasma cells in the bone marrow and the production of M-protein, flow cytometry and serum free light chain (FLC) analyses were carried out in 17 patients with primary systemic AL amyloidosis (mean age, 59.9+/-8.8 years) and controls with M-protein (MGUS controls, n=6) and without it (negative controls, n=9). The patients showed a significantly higher value in the serum predominant FLC:serum creatinine ratio (43.8+/-63.2) and CD38++ CD19- CD56+ subpopulation (monoclonal plasma cells) (2.57+/-5.35%) than either the negative (p<0.0005 and p<0.001, respectively) or MGUS controls (p<0.05). With respect to maturation of plasma cells in the bone marrow, the intermediate (MPC-1+ CD45- CD49e-) and mature (MPC-1+ CD45+ CD49e-) subtypes were significantly higher (49.2+/-23.2%, p<0.005) and lower (27.6+/-21.3%, p<0.005) in the patients than in the negative controls, respectively. The serum predominant FLC:serum creatinine ratio was elevated in parallel with an increase in CD38++ CD19- CD56+ and MPC-1+ CD45- CD49e- cells and a decrease in mature subtypes (MPC-1+ CD45+ CD49e- and MPC-1+ CD45+ CD49e+ cells), There was a significantly positive correlation between the serum predominant FLC:serum creatinine ratio and either CD38++ CD19- CD56+ (r=0.510, p<0.05) or MPC-1+ CD45- CD49e- cells (r=0.481, p<0.05). In primary AL amyloidosis M-protein is probably produced by increased monoclonal plasma cells in the bone marrow, particularly by the intermediate subpopulation with a phenotype of MPC-1+ CD45- CD49e-.
Shimojima
Yasuhiro
Y
Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
Matsuda
Masayuki
M
Gono
Takahisa
T
Ishii
Wataru
W
Fushimi
Tomohisa
T
Hoshii
Yoshinobu
Y
Yamada
Toshiyuki
T
Ikeda
Shu-Ichi
S
D000328:Adult; D000368:Aged; D000686:Amyloidosis / Q000097:blood*; D015703:Antigens, CD / Q000032:analysis*; D001854:Bone Marrow Cells / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000097:blood*; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D009194:Myeloma Proteins / Q000032:analysis; D010950:Plasma Cells / Q000473:pathology*
D015703:Antigens, CD; D007147:Immunoglobulin Light Chains; D009194:Myeloma Proteins; C085016:multiple myeloma M-proteins