Hematopoietic stem cell transplantation for AIDS-related malignancies

From Berlin to London: HIV-1 Reservoir Reduction Following Stem Cell Transplantation

PURPOSE OF REVIEW

Few interventional strategies lead to significant reductions in HIV-1 reservoir size or prolonged antiretroviral (ART)-free remission. Allogeneic stem cell transplantations (SCT) with or without donor cells harboring genetic mutations preventing functional expression of CCR5, an HIV coreceptor, lead to dramatic reductions in residual HIV burden. However, the mechanisms by which SCT reduces viral reservoirs and leads to a potential functional HIV cure are not well understood.

RECENT FINDINGS

A growing number of studies involving allogeneic SCT in people with HIV are emerging, including those with and without transplants involving CCR5^Δ32/Δ32 mutations. Donor cells resistant to HIV entry are likely required in order to achieve permanent ART-free viral remission. However, dramatic reductions in the HIV reservoir secondary to beneficial graft-versus-host effects may lead to loss of HIV detection in blood and various tissues and lead to prolonged time to HIV rebound in individuals with wild-type CCR5 donors. Studies of SCT recipients and those who started very early ART during hyperacute infection suggest that dramatic reductions in reservoir size or restriction of initial reservoir seeding may lead to 8-10 months of time prior to eventual, and rapid, HIV recrudescence. Studies of allogeneic SCT in people with HIV have provided important insights into the size and nature of the HIV reservoir, and have invigorated other gene therapies to achieve HIV cure.

γ-Herpesvirus load as surrogate marker of early death in HIV-1 lymphoma patients submitted to high dose chemotherapy and autologous peripheral blood stem cell transplantation

Autologous stem cell transplantation (ASCT) is a feasible procedure for human immunodeficiency virus-1 (HIV-1) lymphoma patients, whose underlying disease and intrinsic HIV-1- and ASCT-associated immunodeficiency might increase the risk for γ-herpesvirus load persistence and/or reactivation. We evaluated this hypothesis by investigating the levels of Epstein-Barr virus (EBV)- and Kaposi sarcoma-associated herpesvirus (KSHV)-DNA levels in the peripheral blood of 22 HIV-1-associated lymphoma patients during ASCT, highlighting their relationship with γ-herpesvirus lymphoma status, immunological parameters, and clinical events. EBV-DNA was detected in the pre-treatment plasma and peripheral blood mononuclear cells (PBMCs) of 12 (median 12135 copies/mL) and 18 patients (median 417 copies/10⁶ PBMCs), respectively; the values in the two compartments were correlated (r = 0.77, p = 0.0001). Only EBV-positive lymphomas showed detectable levels of plasma EBV-DNA. After debulking chemotherapy, plasma EBV-DNA was associated with lymphoma chemosensitivity (p = 0.03) and a significant higher mortality risk by multivariate Cox analysis adjusted for EBV-lymphoma status (HR, 10.46, 95% CI, 1.11–98.32, p = 0.04). After infusion, EBV-DNA was detectable in five EBV-positive lymphoma patients who died within six months. KSHV-DNA load was positive in only one patient, who died from primary effusion lymphoma. Fluctuations in levels of KSHV-DNA reflected the patient’s therapy and evolution of his underlying lymphoma. Other γ-herpesvirus-associated malignancies, such as multicentric Castleman disease and Kaposi sarcoma, or end-organ complications after salvage treatment were not found. Overall, these findings suggest a prognostic and predictive value of EBV-DNA and KSHV-DNA, the monitoring of which could be a simple, complementary tool for the management of γ-herpesvirus-positive lymphomas in HIV-1 patients submitted to ASCT.

Effect of HIV infection on the outcome of cancer therapy in children

SUMMARY

Systematic studies comparing the outcomes of cancer treatment between children with and without HIV are scarce. The literature seems to suggest that, even with present therapeutic advances, prognosis is poor with HIV infection. The aim of this Review was to assess scientific publications from 1990 to present, addressing the difficulties associated with treatment of cancer in children with AIDS and the adaptive changes in therapy. Although much progress has been achieved, further research is needed about antiretroviral and cytotoxic drug interactions, the optimum use of supportive therapy including stem cells and bone marrow transplant, the timing of the initiation of highly active antiretroviral therapy, and the optimum use of protease inhibitors.

Hematopoietic cell transplantation with cord blood for cure of HIV infections

Hematopoietic cell transplantation (HCT) using CCR5-Δ32/Δ32 stem cells from an adult donor has resulted in the only known cure of human immunodeficiency virus (HIV) infection. However, it is not feasible to repeat this procedure except rarely because of the low incidence of the CCR5-Δ32 allele, the availability of only a small number of potential donors for most patients, and the need for a very close human leukocyte antigen (HLA) match between adult donors and recipients. In contrast, cord blood (CB) transplantations require significantly less stringent HLA matching. Therefore, our hypothesis is that cure of HIV infections by HCT can be accomplished much more readily using umbilical CB stem cells obtained from a modestly sized inventory of cryopreserved CCR5-Δ32/Δ32 CB units. To test this hypothesis, we developed a screening program for CB units and are developing an inventory of CCR5-Δ32/Δ32 cryopreserved units available for HCT. Three hundred such units are projected to provide for white pediatric patients a 73.6% probability of finding an adequately HLA matched unit with a cell dose of ≥2.5 × 10(7) total nucleated cells (TNCs)/kg and a 27.9% probability for white adults. With a cell dose of ≥1 × 10(7) TNCs/kg, the corresponding projected probabilities are 85.6% and 82.1%. The projected probabilities are lower for ethnic minorities. Impetus for using CB HCT was provided by a transplantation of an adult with acute myelogenous leukemia who was not HIV infected. The HCT was performed with a CCR5-Δ32/Δ32 CB unit, and posttransplantation in vitro studies indicated that the patient's peripheral blood mononuclear cells were resistant to HIV infection.

The role of transplantation in diffuse large B-cell lymphoma: the impact of rituximab plus chemotherapy in first-line and relapsed settings

Rituximab has improved the prognosis of patients with diffuse large B-cell lymphoma, but a high proportion of patients with advanced disease will relapse or will fail to achieve a remission with front-line treatment. Salvage chemotherapy, followed by high-dose chemotherapy or radiation therapy and autologous stem cell transplantation, remains the best treatment option for such patients, especially those who retain chemosensitivity. Allogeneic transplantation is under investigation in this setting, often as a treatment for relapse after autologous transplantation. Treatment-related mortality due to graft-versus-host disease, preparative regimen toxicity, and poor immune recovery often limits its benefits. This article reviews the role of hematopoietic stem cell transplantation in the treatment of diffuse large B-cell lymphoma, the incorporation of rituximab, and avenues of clinical investigation in this rapidly evolving field.