Immunologic Recovery after Autologous Transplant in Multiple Myeloma and Progression Free Survival

Several factors influencing disease progression and survival have been identified in multiple myeloma (MM). We analysed a series of 49 consecutive patients with MM that underwent autologous haematopoietic progenitor cell transplant (HPCT) in one center regarding the following variables: use of G-CSF for haematopoietic recovery post-transplant; recovery of normal IgM levels at day +100 post-transplant; levels of lymphocytes namely of the CD4+ and CD8+ subsets also at day +100. Before 2006, all patients had G-CSF starting 24 hours after the cell infusion until neutrophil > 500×10^9/L in two consecutive days; in the years 2006–2008, no G-CSF was given to transplanted patients. A historical comparison was done and at the time of this study no significant difference in progression free survival (Kaplan-Meyer analysis), was detected between the two groups, possibly due to the shorter follow-up of the “no G-CSF” (n=19) group; nevertheless median progression free survival (PFS) in the “G-CSF” group was 12 months while median PFS was not attained in the “no G-CSF” group (median follow-up = 7 months). Post transplant IgM levels were also determined in 39 patients. Eighteen patients recovered normal IgM levels at day +100 (46.8 %) and 21 (53.8 %) did not. Comparison of Kaplan-Meyer curves for the two groups did not show any statistically significant difference but there is a sharp difference between median PFS of the “low IgM” (10 months) and the “normal IgM” (27 months) groups. CD4/CD8 ratio was determined in 18 patients at day +100. The ratio varied between 0 and 0.63 (median – 0.305). No correlation was found between post-transplant IgM recovery and CD4/CD8 ratio. In conclusion, in our series of MM patients treated with autologous HPCT we could not find a definite relationship between immunologic recovery and response to treatment although there is a trend to a better outlook of the patients which recover normal IgM levels. It is also uncertain whether use of G-CSF in the post-transplant period would have any effect on disease behaviour.