Different immune reconstitution in multiple myeloma, chronic myeloid leukemia and acute myeloid leukemia patients after allogeneic transplantation of peripheral blood stem cells

Cure of multiple myeloma -- more hype, less reality

Randomized studies have firmly established the role of autologous transplant as initial therapy in multiple myeloma (MM). Indeed, MM has emerged as the commonest indication for autologous SCT in North America. The conceptual basis for high-dose therapy is the goal of complete remission (CR) through steep reduction in tumor burden affected by single and tandem transplants. Careful analysis of the data challenges the notion of CR as a surrogate to success. Intrinsically aggressive MM, defined by known unfavorable biologic risk factors, overrides the benefit of CR. In contrast, subgroups of patients with favorable biological risk factors may achieve prolonged survival, often without ever achieving CR. Unfortunately, even with tandem transplants, there is no plateau in survival curves. To this end, sequential autologous followed by nonmyeloablative allotransplants are a novel attempt at 'curing' myeloma, but the results thus far have failed to show a definite plateau in survival. Given the improvements in supportive care and concomitant reduction in transplant-related mortality, conventional myeloablative allogeneic transplants need to be re-examined as an option in high-risk aggressive myeloma. At the same time, novel antimyeloma therapies, newer risk stratification and staging tools are transforming the treatment algorithm. We examine the changing role of transplantation in myeloma in the context of novel drug therapy, biologic risk stratification and improving supportive care while arguing that the current 'one size fits all' transplant approaches are far from a cure.

Improved outcome of allogeneic transplantation in high-risk multiple myeloma patients after nonmyeloablative conditioning

PURPOSE

We present our experience with relapsed and recently diagnosed patients with high-risk multiple myeloma (MM) receiving immunosuppressive, nonmyeloablative melphalan (MEL)-based conditioning regimens (mini-allograft).

PATIENTS AND METHODS

Thirty-one MM patients received allografts from HLA-matched siblings (n = 25) or unrelated donors (n = 6) using a mini-allograft. Seventeen had progressive disease (PD) and 14 had responsive disease (RD) (six with primary RD and eight with responsive relapse). Thirty patients had received one (n = 13) or two or more (n = 17) prior autologous transplantations (ATs). Median age was 56 years (range, 38 to 69 years). Twenty-one patients had chromosome 13 abnormality. Two patients were hemodialysis dependent. Blood and bone marrow grafts were administered to 28 and three patients, respectively. Donor lymphocyte infusions were given to 18 patients either to attain full donor chimerism (n = 6) or to eradicate residual disease (n = 12).

RESULTS

By day 100, 25 (89%) of 28 patients were full donor chimeras, one was a mixed chimera, and two had autologous reconstitution. Acute graft-versus-host disease (GVHD) developed in 18 patients (58%), and 10 progressed to chronic GVHD (limited in six and extensive in four). At a median follow-up of 6 months, 19 (61%) of 31 patients achieved complete/near complete remission. Twelve patients (39%) have died: three of PD, three of early treatment-related mortality (TRM) (before day 100), and six of late TRM. Median overall survival (OS) was 15 months. At 1 year, there was a significantly longer event-free survival (86% v 31%, P =.01) and OS (86% v 48%, P =.04) when a mini-allograft was performed after one versus two or more prior ATs, respectively. When compared with historical MM controls (n = 93) receiving conventional allografts, early TRM was significantly lower (10% v 29%, P =.03), and OS at 1 year was better (71% v 45%; P =.08) in the mini-allograft MM patients.

CONCLUSION

Mini-allograft induced excellent disease control in MM patients with high-risk disease, but is still associated with a significant GVHD.

Immunologic recovery after autologous blood stem cell transplantation in patients with AL-amyloidosis

We prospectively studied absolute lymphocyte (ALC) and monocyte counts (AMC), lymphocyte subsets and proliferative in vitro responses to mitogen and antigen in 12 patients with AL-amyloidosis (AL) undergoing autologous blood stem cell transplantation (SCT) with high-dose i.v. melphalan. Myeloid and lymphoid recovery (>500 per microl) occurred in a median of 10 days post SCT. While there was a continuous decline in the number of CD4+ T cells at 3 months, ALC, AMC, B cells (CD19+), CD8+ T cells, and NK cells (CD16+/56+) returned to baseline. While T cell proliferative responses to phytohemagglutinin (PHA) remained depressed, B cell function measured by the proliferative response to staphylococcal antigen returned to baseline by 3 months. To supplement our findings, we retrospectively evaluated ALC, AMC and serum immunoglobulin levels in a separate group of patients treated with the same protocol at our institution. ALC and AMC recovery was similar to the pattern observed in the initial study group. Immunoglobulin levels remained within normal ranges at 3 and 12 months after SCT. Of 50 patients who were followed for a minimum of 1 year following SCT, seven (14%) developed shingles and one (2%) had PCP pneumonia. In conclusion, cellular immune function, reflected by absolute numbers of CD4+ T cells and PHA responsive T cell proliferation, is significantly suppressed at 3 months after SCT in patients with AL, and this post-transplant immunosuppression is associated with a low but clinically meaningful occurrence of opportunistic infections typical of T cell immunosuppression.