Allogeneic stem cell transplantation for HIV-positive patients with hematologic malignancies

Haematopoietic stem-cell transplantation in an HIV endemic area: time to consider donors exposed to or living with HIV

South Africa has more than 8 million people living with HIV. However, the number of patients undergoing haematopoietic stem-cell transplantation (HSCT) in South Africa is far below the target number. Donor numbers are insufficient to meet demand. Both HSCT and solid organ transplantation have proved successful in people living with HIV. Solid organ transplantation also has good outcomes when both donors and recipients have HIV. This Personal View explores the possible inclusion of people living with HIV and umbilical cord blood from HIV-negative infants exposed to HIV as donor sources for HSCT. Beyond the risk of HIV transmission, additional complications must be considered, such as delayed or inadequate immune reconstitution and an increased risk of haematological abnormalities and malignancies. Interactions between antiretroviral drugs and drugs used in the conditioning regimen, as well as the need to maintain virological suppression when gastrointestinal absorption deteriorates, are additional complicating factors. The process also requires more stringent ethical processes to be in place to minimise physical and emotional harm. However, in an HIV endemic country, people living with HIV or donors exposed to HIV must be considered as part of a multidisciplinary collaborative effort to provide more patients with the opportunity to have a life-saving HSCT.

Next-generation probiotics: a promising approach towards designing personalized medicine

Second brain, forgotten organ, individual's identity card, and host's fingerprint are the few collective terms that are often used to describe the gut microbiome because of its variability, accountability, and its role in deciding the host's health. Also, the understanding of this host health-gut microbiota relationship can create an opportunity to control an individual's health by manipulating the gut microbiota composition. Several approaches like administration of probiotic, prebiotics, synbiotics, faecal microbiota transplantation have been tried to mitigate the dysbiosis originated ill effects. But the effects of these approaches are highly generic and non-specific. This creates the necessity to design personalized medicine that focuses on treatment of specific disease considering the individual specific gut microbiome. The health promoting commensals could be the new promising prophylactic and therapeutic agents for designing personalized medicine. These commensals are designated as next-generation probiotics (NGPs) and their unusual characteristics, unknown identity and special growth requirements have presented difficulties for researcher, industrial exploitation, and regulatory agencies. In this perspective, this review discusses the concept of NGPs, NGP candidates as tool for designing personalized medicine, designer probiotics as NGPs, required regulatory framework, and propose a road map to develop the NGP based product.

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.

Acute Myeloid Leukemia in Patients Living with HIV Infection: Several Questions, Fewer Answers

Both human immunodeficiency virus (HIV) infection and acute myeloid leukemia (AML) may be considered relatively uncommon disorders in the general population, but the precise incidence of AML in people living with HIV infection (PLWH) is uncertain. However, life expectancy of newly infected HIV-positive patients receiving anti-retroviral therapy (ART) is gradually increasing, rivaling that of age-matched HIV-negative individuals, so that the occurrence of AML is also expected to progressively increase. Even if HIV is not reported to be directly mutagenic, several indirect leukemogenic mechanisms, mainly based on bone marrow microenvironment disruption, have been proposed. Despite a well-controlled HIV infection under ART should no longer be considered per se a contraindication to intensive chemotherapeutic approaches, including allogeneic hematopoietic stem cell transplantation, in selected fit patients with AML, survival outcomes are still generally unsatisfactory. We discussed several controversial issues about pathogenesis and clinical management of AML in PLWH, but few evidence-based answers may currently be provided, due to the limited number of cases reported in the literature, mainly as case reports or small retrospective case series. Prospective multicenter clinical trials are warranted to more precisely investigate epidemiology and cytogenetic/molecular features of AML in PLWH, but also to standardize and further improve its therapeutic management.

Allogeneic stem-cell transplantation in HIV-1-infected patients with high-risk hematological disorders

INTRODUCTION

Although a number of patients with HIV infection and hematological disease have successfully undergone allogeneic hematopoietic stem-cell transplantation (HSCT), short and long-term outcomes remain not well known. We report the largest Spanish experience treating HIV-infected adult patients with high-risk hematological malignancies with allogeneic HSCT.

METHODS

We retrospectively reviewed 22 HIV-positive patients who received allogeneic HSCT in five centers in Spain.

RESULTS

A total of 22 patients with high-risk hematological malignancies were transplanted between 1999 and 2018. Median age was 44 years. With a median follow-up of 65 months (8-112), overall survival and event-free survival were 46%. Nonrelapse mortality was 14% at 12 months and relapse was 24% at 24 months. Grade II-IV acute graft-versus-host disease (GVHD) rate was 44%, and moderate/severe chronic GVHD rate was 41% at 24 months. All patients received combination antiretroviral therapy. Two patients showed severe toxicity related to drug interaction with antiretroviral therapy. 68% of patients showed infectious complications with viral infections as the most frequent cause. Two patients had invasive aspergillosis and one patient presented disseminated tuberculosis. All survivors except one maintained undetectable HIV load at last follow-up after HSCT.

CONCLUSION

Allogeneic HSCT is an effective therapy for high-risk hematological malignancies in patients with HIV infection, and long-term HIV suppression with combination antiretroviral therapy is feasible. However, drug interactions with antiretroviral agents, occurrence of GVHD, and frequent infectious complications account for a complex procedure in this population. Selected HIV-infected patients with hematologic malignancies should be considered for allo-HSCT when indicated, in experienced centers.

A Brazilian university hospital position regarding transplantation criteria for HIV-positive patients according to the current literature

Human immunodeficiency virus (HIV) infection was considered a contraindication for solid organ transplantation (SOT) in the past. However, HIV management has improved since highly active antiretroviral therapy (HAART) became available in 1996, and the long-term survival of patients living with HIV has led many transplant programs to reevaluate their policies regarding the exclusion of patients with HIV infection.Based on the available data in the medical literature and the cumulative experience of transplantation in HIV-positive patients at our hospital, the aim of the present article is to outline the criteria for transplantation in HIV-positive patients as recommended by the Immunocompromised Host Committee of the Hospital das Clínicas of the University of São Paulo.

Risks and Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation for Hematologic Malignancies in Patients with HIV Infection

Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative therapy for hematologic malignancies in persons living with HIV (PLHIV), however, uncertainties exist in many domains related to their care, including optimal donor selection, conditioning regimen, immunosuppression for graft-versus-host disease (GVHD), and long-term outcomes. We undertook a comprehensive systematic review from multiple databases to evaluate the foregoing uncertainties. The final sample comprised 49 patients (median age at HCT, 34 years; 46 males [93.8%]). Acute GVHD (aGVHD) was reported in 19 patients (59.3%) in the overall cohort, with grade II in 12 (37.5%) and grade III in 2 (6.2%). In the entire cohort, overall survival (OS) was 81.6% at 6 months and 56.6% at 12 months. Among 32 patients, the OS at 6 months was 73.3% for patients who received myeloablative conditioning (MAC) and 88.2% for those who received reduced-intensity conditioning (RIC), and OS at 12 months was 53.3% for MAC and 58.8% for RIC. Twenty-four patients were alive in complete remission on long-term follow-up, with 25 deaths reported. Fifteen deaths (60%) occurred due to relapse, including 3 (12%) from infection, 2 (8%) from GVHD, and 5 (20%) from other causes, including renal failure, respiratory failure, and liver failure. To our knowledge, this is the largest series of allo-HCT in PLHIV reported to date, and our results indicate that clinical outcomes (including engraftment, infection rate, and survival) are not significantly different from those in patients without HIV (historical controls). RIC regimens are associated with a slightly greater likelihood of survival compared with MAC regimens. Prospective trials are critically needed to evaluate the optimal conditioning regimens, ideal donor source, and most appropriate GVHD prophylaxis.

Next generation probiotics in disease amelioration

Studies on the role of gut commensal bacteria in health development have rapidly attracted much more attention beyond the classical pathogens over the last decade. Many important reports have highlighted the changes in the gut microbiota (dysbiosis) are closely related to development of intra- and extra-intestinal, chronic inflammation related diseases such as colitis, obesity/metabolic syndromes, diabetes mellitus, liver diseases, cardiovascular diseases and also cancer and neurodegenerative diseases. To circumvent these difficulties, the strategy of modulating the structure of the gut microbiota has been under intensive study and shed more light on amelioration of these inflammation related diseases. While traditional probiotics generally show marginal ameliorative effects, emerging next generation probiotics start to reveal as new preventive and therapeutic tools. Recent studies have unraveled many potential next generation probiotics (NGP). These include Prevotella copri and Christensenella minuta that control insulin resistance, Parabacteroides goldsteinii, Akkermansia muciniphila and Bacteroides thetaiotaomicron that reverse obesity and insulin resistance, Faecalibacterium prausnitzii that protects mice against intestinal diseases, and Bacteroides fragilis that reduces inflammation and shows anticancer effect. New agents will soon be revealed for targeted therapy on specific inflammation related diseases. The important roles of next generation probiotics and gut microbiota normobiosis on the maintenance of intestinal integrity and homeostasis are emphasized.

How I treat patients with HIV-related hematological malignancies using hematopoietic cell transplantation

Hematopoietic cell transplantation (HCT) has now been shown to be safe and effective for selected HIV-infected patients with hematological malignancies. Autologous HCT is now the standard of care for patients with HIV-related lymphomas who otherwise meet standard transplant criteria. Limited data also support use of allogeneic HCT (alloHCT) in selected HIV-infected patients who meet standard transplant criteria. We recommend enrolling patients in clinical trials that offer access to CCR5Δ32 homozygous donors, if available. HIV-infected patients requiring HCT may also be considered for participation in trials evaluating the activity of gene-modified hematopoietic stem cells in conferring resistance to HIV infection. To be considered for HCT, patients must have HIV infection that is responsive to combination antiretroviral therapy (cART). Careful planning for the peri-HCT management of the cART can avoid risk of significant drug interactions and development of cART-resistant HIV. In general, we recommend against the use of boosted proteasome inhibitors and nonnucleotide reverse transcriptase inhibitors in the cART regimen, in favor of nucleoside reverse transcriptase inhibitors and integrase inhibitors (without cobicistat). After HCT, patients must be closely monitored for development of opportunistic infections (OI), such as cytomegalovirus. Prevention of OI should include prophylactic and pre-emptive antimicrobials.

CCR5-edited gene therapies for HIV cure: Closing the door to viral entry

Human immunodeficiency virus (HIV) was first reported and characterized more than three decades ago. Once thought of as a death sentence, HIV infection has become a chronically manageable disease. However, it is estimated that a staggering 0.8% of the world's population is infected with HIV, with more than 1 million deaths reported in 2015 alone. Despite the development of effective anti-retroviral drugs, a permanent cure has only been documented in one patient to date. In 2007, an HIV-positive patient received a bone marrow transplant to treat his leukemia from an individual who was homozygous for a mutation in the CCR5 gene. This mutation, known as CCR5Δ32, prevents HIV replication by inhibiting the early stage of viral entry into cells, resulting in resistance to infection from the majority of HIV isolates. More than 10 years after his last dose of anti-retroviral therapy, the transplant recipient remains free of replication-competent virus. Multiple groups are now attempting to replicate this success through the use of other CCR5-negative donor cell sources. Additionally, developments in the use of lentiviral vectors and targeted nucleases have opened the doors of precision medicine and enabled new treatment methodologies to combat HIV infection through targeted ablation or down-regulation of CCR5 expression. Here, we review historical cases of CCR5-edited cell-based therapies, current clinical trials and future benefits and challenges associated with this technology.