Susana Fraind

Oligoclonal bands and immunoglobulin isotype switch during monitoring of patients with multiple myeloma and autologous hematopoietic cell transplantation: a 16-year experience.

Abstract 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 β2-microglobulin (β2M) 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, β2M, 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. Clin Chem Lab Med 2010;48:727–31.