Prognostic impact of serum immunoglobulin heavy/light chain ratio in patients with multiple myeloma in complete remission after autologous stem cell transplantation.

Immunoglobulin heavy/light chain (HLC) ratios were studied in 37 patients with multiple myeloma in complete remission after autologous hematopoietic stem cell transplantation. Increased IgAκ/IgAλ and IgMκ/IgMλ ratios were associated with longer progression-free survival (P = .006 and .01, respectively). A statistical trend toward a longer overall survival was also observed for the IgAκ/IgAλ ratio (P = .068). Considering the original immunoglobulin isotype, our results indicate that an increased κ/λ ratio of the uninvolved isotype is associated with longer progression-free survival and overall survival. This is the first report demonstrating the association between the HLC ratio and sustained complete remission in patients with multiple myeloma. Our results suggest that the HLC ratio is a surrogate marker of immune recovery after myeloablative transplantation, rather than as a marker of minimal residual disease.