Clin Biochem Rev 2009;30(iiii):113-118

Significance of Abnormal Protein Bands in Patients with Multiple
Myeloma following Autologous Stem Cell Transplantation

Sara L. Hall,1 Jill Tate,2Devinder Gill,1,3 *Peter Mollee1,3

1Haematology Department, Pathology Queensland, Princess Alexandra Hospital, Brisbane, Qld 4102
2Department of Chemical Pathology, Pathology Queensland, Royal Brisbane and Women’s Hospital,
Brisbane, Qld 4029
3Haematology Department, Cancer Services, Princess Alexandra Hospital, Brisbane, Qld 4102, Australia
*For correspondence: Dr Peter Mollee e-mail: peter_mollee@health.qld.gov.au

Aim: We studied the characteristics of small abnormal protein bands (APB) (including oligoclonal bands and new apparent monoclonal bands) that are frequently detected by serum protein electrophoresis (SPEP) and isoelectric focusing (IEF) in the post-autologous stem cell transplant setting.
Methods: In a retrospective analysis of patients with multiple myeloma undergoing transplantation, paraprotein identity and quantification were performed using standard immunofixation electrophoresis. The nature of any new bands was determined by IEF which distinguished between oligoclonal bands and apparent monoclonal bands.
Results: Of 49 myeloma cases, the median follow-up was 33.7 months (range, 5.6-97.5 months) and 24 patients had relapsed. Thirty six (73%) developed APB. 22 patients had more than one episode of APB and 6 patients had more than 2 episodes resulting in a total of 69 episodes of APB observed post-transplant. IEF demonstrated 54 of these APB were oligoclonal bands and 15 appeared to be monoclonal. Of the 15 episodes of apparent monoclonal bands, 10 had differing heavy or light chain restriction compared to the original myeloma paraprotein and 5 had the same heavy and light chain restriction but different band location in the SPEP lane. Ten of these apparent monoclonal bands resolved, 5 persisted, and only one represented true disease progression. The presence of APB impacted favourably on event-free survival (p=0.05).
Conclusion: Small APB are very frequent post-transplant for myeloma, and IEF can identify these APB as oligoclonal or monoclonal. Apparent monoclonal bands may represent relapsed disease, but in the vast majority of cases it does not, and most likely represents a transient phenomenon representing regeneration of a limited immune response.