9: Allogeneic hematopoietic stem cell transplantation in HIV-positive patients with malignant and non-malignant disorders

Graft-versus-leukaemia effect post fludarabine, melphalan and alemtuzumab reduced intensity allogeneic stem cell transplantat in HIV-infected patient with acute myeloid leukaemia

Allogeneic stem cell transplantation (Allo-HSCT) is sine qua non to cure high-risk acute myeloid leukaemia (AML). In spite the advent of highly active antiretroviral treatment, HIV-infected patients display a remarkable risk for haematological neoplasms such as non-Hodgkin lymphomas, Hodgkin lymphoma and acute leukaemia. Several case series have confirmed the efficacy of the autologous stem cell transplantation for the treatment of non-Hodgkin lymphomas in the HIV setting. Nonetheless, there is a paucity of data for the role of the Allo-HSCT in HIV-infected individuals with haematological malignancies. Herein, we presented the successful long-term outcome of a HIV-infected patient who received reduced intensity conditioned, matched unrelated donor transplant with alemtuzumab as graft-versus-host disease prophylaxis for therapy-related acute myeloid leukaemia. We propose that Allo-HSCT in HIV patients is safe and that alemtuzumab-based conditioning could further work to eradicate HIV in those whose donor is not CCR5 homozygous.

Hematopoietic stem cell transplantation for AIDS-related malignancies

PURPOSE OF REVIEW

AIDS-related malignancies are an ongoing cause of mortality in individuals with HIV infection. In the HIV-negative setting, high-dose chemotherapy or stem cell transplantation is an option for patients with hematologic malignancies. Prior to the advent of effective HIV therapy, stem cell transplantation was not feasible for HIV-positive patients. The purpose of this article is to explore the transplant options for HIV-positive patients after widespread use of highly active antiretroviral therapy.

RECENT FINDINGS

Early autologous stem cell transplantation has studies had high relapse rates but they demonstrated that mobilization and engraftment of autologous stem cells were possible in AIDS patients. Recently, in less advanced AIDS lymphoma, autologous stem cell transplantation has resulted in low transplant-related mortality and durable remissions. In addition, case-control studies of HIV-positive versus HIV-negative lymphoma patients undergoing autologous stem cell transplantation have shown similar transplant-related mortality and overall survival. The feasibility of allogeneic stem cell transplantation in HIV-infected individuals is less tested. There are challenges of drug interactions between highly active antiretroviral therapy and immunosuppressive agents as well as the potential for higher infection rates.

SUMMARY

The potential future applications of autologous and allogeneic stem cell transplantation are the cure of the malignancy as well as the underlying HIV infection by either transplantation of naturally resistant or genetically modified stem cells.

Transplantation of selected or transgenic blood stem cells - a future treatment for HIV/AIDS?

Interaction with the chemokine receptor, CCR5, is a necessary precondition for maintaining HIV-1 infection. Individuals with the CCR5-delta32 deletion who lack this receptor are highly resistant to infection by the most common forms of HIV-1. We recently reported on the successful transplantation in an HIV-1-positive patient of allogeneic stem cells homozygous for the CCR5-delta32 allele, which stopped viral replication for more than 27 months without antiretroviral therapy.Here, we report on the results of a meeting regarding the potential implications and future directions of stem cell-targeted HIV treatments. The meeting drew together an international panel of hematologists, immunologists, HIV specialists and representatives from bone marrow donor registries.The meeting came to an agreement to support further attempts to use CCR5-delta32 deleted stem cells, for example, prescreened cord blood stem cells, to treat probable HIV-1-positive patients with malignancies. Furthermore, improvement of HIV-1 therapy that interferes with the entry mechanism seems to be a promising approach in HIV-1-infected patients with no matching CCR5-delta32 deleted donor.

Stem cell transplantation in HIV-infected patients

Lymphoma remains a leading cause of mortality in HIV-infected patients. In the HIV-negative setting, high-dose therapy with autologous stem cell transplantation has been a long accepted treatment for certain malignancies such as lymphoma and leukemia. Early transplant trials excluded older patients and patients with comorbidities such as HIV infection. The procedure-related mortality of transplantation, however, has decreased both due to the use of peripheral blood stem cells instead of bone marrow and due to the use of new reduced intensity conditioning regimens. During this same era, the treatment of HIV infection has also become more effective. Patients are no longer dying of opportunistic infections and in addition, their hematologic function has improved. With these advances in HIV therapy, it is possible for HIV-infected patients to mobilize an adequate number of stem cells for an autologous transplant. In addition, with appropriate antiretroviral therapy and infection prophylaxis, the HIV-infected patient can tolerate intensive doses of chemotherapy. This review will summarize clinical trials of autologous stem cell transplantation in HIV-positive patients. Furthermore, the field of solid-organ transplantation has grown to also include HIV-positive patients. The challenges in solid-organ transplantation are similar to allogeneic stem cell transplantation, namely that patients require chronic immunosuppression. This article will also review some of the approaches to allogeneic stem cell transplantation in the HIV-positive patient and provide a rationale for the broader use of stem cell transplantation for appropriate HIV-related hematologic malignancies.