Oligoclonal bands and immunoglobulin isotype switch during monitoring of patients with multiple myeloma and autologous hematopoietic cell transplantation: a 16-year experience.
BACKGROUND
Over the last 20 years, high dose therapy followed by hemopoietic stem cell transplantation has been employed in patients with multiple myeloma (MM). During 16 years of follow-up, the degree of tumor response and survival in 238 patients with autologous stem cell transplantation (ASCT) and changes in the serum protein electrophoretic pattern were analyzed.


METHODS
Agarose gel electrophoresis with densitometric analysis and immunofixation were performed to evaluate serum monoclonal protein. IgM, IgA, IgG and beta(2)-microglobulin (beta2M) were quantitated. Urine protein electrophoresis with IF was performed on cellulose acetate gel using colloidal silver staining without concentrating.


RESULTS
After 34 months of follow-up (range 1-160 months), eight patients (3.4%) showed a distinct monoclonal protein band that was different from their original isotype switch. This was observed to be a transient phenomenon (22.2 months). Thirty-seven patients (15.5%) developed oligoclonal bands (OB) between the first and the twentieth month after ASCT (mean 4.4 months), which persisted for 7.9 months (1-36 months). The mean overall survival time was statistically different (p<0.05) between the group with OB and the group without them. Mean values of serum albumin, beta2M, and non-involved immunoglobulins did not show statistical differences.


CONCLUSIONS
The occurrence of OB could be a potential favorable prognostic marker after transplantation due to the prolonged survival observed. Close follow-up of anomalous protein bands, either in serum or urine, is essential due to the additional difficulty in interpretation when the therapeutic response and evolution are evaluated.
Alejandre
Mariel Emilce
ME
Department of Clinical Biochemistry, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina. marielalejandre@hotmail.com
Madalena
Leticia Bibiana
LB
Pavlovsky
Miguel Arturo
MA
Facio
Maria Laura
ML
Corrado
Claudia
C
Milone
Gustavo
G
Bresciani
Pablo Diego
PD
Fraind
Susana Alicia
SA
Pavlovsky
Santiago
S
Pizzolato
Marco Antonio
MA
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003720:Densitometry; D004587:Electrophoresis, Agar Gel; D005260:Female; D005500:Follow-Up Studies; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000097:blood*; D007525:Isoelectric Focusing; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D043025:Oligoclonal Bands / Q000097:blood*; D011379:Prognosis; D014182:Transplantation, Autologous
D015415:Biomarkers; D007132:Immunoglobulin Isotypes; D043025:Oligoclonal Bands