Pablo Bresciani

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.

Serum free light chains and oligoclonal bands in patients with multiple myeloma and autologous stem cell transplantation.

Abstract Background: To establish stringent complete remission (SCR) in patients with multiple myeloma (MM), it is currently recommended to obtain a normal serum free light chains (sFLC) ratio. The appearance of serum oligoclonal bands (OB) after autologous stem cell transplantation (ASCT) is considered a favorable prognostic factor. The objective of this study was to examine sFLC for assessing SCR in patients with MM, and ASCT with OB. We also examined how capillary electrophoresis (CE) compares with agarose gel electrophoresis (Aga) in identifying oligoclonal bands. Methods: Out of 238 patients studied in our institution between April 1992 and December 2008 a serum protein electrophoresis (SPE) was performed by means of CE and sFLC determination on 37 patients with MM in complete remission (CR), ASCT and OB presence were assigned by conventional Aga electrophoresis and IF. Results: Statistically significant differences (SSD) were found when comparing CE vs. Aga, regarding BO visualization in SPE, favoring the latter. In connection with sFLC, the group of patients with an abnormal ratio presented elevated values in the γ-globulin zone of the SPE, whereas the group of patients with a normal ratio of sFLC presented with normal values resulting in SSD between the groups. Conclusions: It is essential to perform immunofixation to certify the presence of OB, especially if CE is used as it is difficult to distinguish them using this method. A normal sFLC was observed in most of the patients with OB and normal values of the SPE γ-globulin zone. The above-mentioned information might demonstrate a limitation of sFLC test in SCR evaluation for patients with MM, ASCT and CR if OB has been detected.