Bone-marrow transplantation in AIDS

HLA-mismatched allogeneic adoptive immune therapy in patients with severely immunosuppressed AIDS: a multicenter, open-label, controlled, phase 2a study

Recurrent opportunistic infections (OIs) in patients with severely immunosuppressed AIDS remain an unresolved medical challenge despite advancements in antiretroviral therapy (ART). To address this gap, we developed an HLA-mismatched allogeneic adoptive immune therapy (AAIT) specifically targeting this patient population. The safety and efficacy of this novel therapeutic approach were preliminarily confirmed in our phase 1 trial. Subsequently, a multicenter, open-label, controlled, phase 2a trial was conducted to evaluate the efficacy of AAIT in combination with ART compared with the conventional ART-only regimen. No difference in the incidence of adverse events (AEs) was observed between the two groups at the 96-week follow-up. AAIT treatment improved CD4+ T cell recovery at weeks 72 (P = 0.048) and 96 (P = 0.024) compared to the Control Group. Additionally, stratified analysis of patients in the AAIT Group showed that donor/recipient sex mismatch was significantly associated with the likelihood of patients achieving an immunological response (OR = 8.667; 95% CI, 2.010-37.377; P = 0.004). These findings suggest that AAIT serves as a promising adjunct therapy for improving the outcomes of patients with severely immunosuppressed AIDS. Further studies are needed to elucidate the immunological mechanisms underlying AAIT and identify the subpopulations that respond optimally to this therapeutic approach. This trial is registered at www.clinicaltrials.gov (NCT04098770).Trial registration: ClinicalTrials.gov identifier: NCT04098770.Trial registration: ClinicalTrials.gov identifier: NCT02651376.

Eliminating the HIV tissue reservoir: current strategies and challenges

BACKGROUND

Acquired immunodeficiency syndrome (AIDS) is still one of the most widespread and harmful infectious diseases in the world. The presence of reservoirs housing the human immunodeficiency virus (HIV) represents a significant impediment to the development of clinically applicable treatments on a large scale. The viral load in the blood can be effectively reduced to undetectable levels through antiretroviral therapy (ART), and a higher concentration of HIV is sequestered in various tissues throughout the body, forming the tissue reservoir - the source of viremia after interruption treatment.

METHODS

We take the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) as a guideline for this review. In June 2023, we used the Pubmed, Embase, and Scopus databases to search the relevant literature published in the last decade.

RESULTS

Here we review the current strategies and treatments for eliminating the HIV tissue reservoirs: early and intensive therapy, gene therapy (including ribozyme, RNA interference, RNA aptamer, zinc finger enzyme, transcriptional activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats/associated nuclease 9 (CRISPR/Cas9)), 'Shock and Kill', 'Block and lock', immunotherapy (including therapeutic vaccines, broadly neutralising antibodies (bNAbs), chimeric antigen receptor T-cell immunotherapy (CAR-T)), and haematopoietic stem cell transplantation (HSCT).

CONCLUSION

The existence of an HIV reservoir is the main obstacle to the complete cure of AIDS. Choosing the appropriate strategy to deplete the HIV reservoir and achieve a functional cure for AIDS is the focus and difficulty of current research. So far, there has been a lot of research and progress in reducing the HIV reservoir, but in general, the current research is still very preliminary. Much research is still needed to properly assess the reliability, effectiveness, and necessity of these strategies.

HIV cure strategies: which ones are appropriate for Africa?

Although combination antiretroviral therapy (ART) has reduced mortality and improved lifespan for people living with HIV, it does not provide a cure. Patients must be on ART for the rest of their lives and contend with side effects, unsustainable costs, and the development of drug resistance. A cure for HIV is, therefore, warranted to avoid the limitations of the current therapy and restore full health. However, this cure is difficult to find due to the persistence of latently infected HIV cellular reservoirs during suppressive ART. Approaches to HIV cure being investigated include boosting the host immune system, genetic approaches to disable co-receptors and the viral genome, purging cells harboring latent HIV with latency-reversing latency agents (LRAs) (shock and kill), intensifying ART as a cure, preventing replication of latent proviruses (block and lock) and boosting T cell turnover to reduce HIV-1 reservoirs (rinse and replace). Since most people living with HIV are in Africa, methods being developed for a cure must be amenable to clinical trials and deployment on the continent. This review discusses the current approaches to HIV cure and comments on their appropriateness for Africa.

HLA-mismatched allogeneic adoptive immune therapy in severely immunosuppressed AIDS patients

Severely immunosuppressed AIDS patients with recurrent opportunistic infections (OIs) represent an unmet medical need even in the era of antiretroviral therapy (ART). Here we report the development of a human leukocyte antigen (HLA)-mismatched allogeneic adaptive immune therapy (AAIT) for severely immunosuppressed AIDS patients. Twelve severely immunosuppressed AIDS patients with severe OIs were enrolled in this single-arm study. Qualified donors received subcutaneous recombinant granulocyte-colony-stimulating factor twice daily for 4-5 days to stimulate hematopoiesis. Peripheral blood mononuclear cells were collected from these donors via leukapheresis and transfused into the coupled patients. Clinical, immunological, and virological parameters were monitored during a 12-month follow-up period. We found AAIT combined with ART was safe and well-tolerated at the examined doses and transfusion regimen in all 12 patients. Improvements in clinical symptoms were evident throughout the study period. All patients exhibited a steady increase of peripheral CD4+ T cells from a median 10.5 to 207.5 cells/μl. Rapid increase in peripheral CD8+ T-cell count from a median 416.5 to 1206.5 cells/μl was found in the first 90 days since initiation of AAIT. In addition, their inflammatory cytokine levels and HIV RNA viral load decreased. A short-term microchimerism with donor cells was found. There were no adverse events associated with graft-versus-host disease throughout the study period. Overall, AAIT treatment was safe, and might help severely immunosuppressed AIDS patients to achieve a better immune restoration. A further clinical trial with control is necessary to confirm the efficacy of AAIT medication.

HIV Eradication Strategies: Implications for the Central Nervous System

PURPOSE OF REVIEW

In addition to preventive protocols and antiretroviral therapy, HIV-1 eradication has been considered as an additional strategy to help fight the AIDS epidemic. With the support of multiple funding agencies, research groups worldwide have been developing protocols to achieve either a sterilizing or a functional cure for HIV-infection.

RECENT FINDINGS

Most of the studies focus on the elimination or suppression of circulating CD4+ T cells, the best characterized HIV-1 latent reservoir. The role of the central nervous system (CNS) as a latent reservoir is still controversial. Although brain macrophages and astrocytes are susceptible to HIV-1 infection, it has not been ascertained whether the CNS carries latent HIV-1 during cART and, if so, whether the virus can be reactivated and spread to other compartments after ART interruption. Here, we examine the implications of HIV-1 eradication strategies on the CNS, regardless of whether it is a true latent reservoir and, if so, whether it is present in all patients.

Stem cell transplantation in strategies for curing HIV/AIDS

HIV-1 can persist in a latent form in resting memory CD4+ cells and macrophages carrying an integrated copy of the HIV genome. Because of the presence of these stable reservoir cells, eradication by antiretroviral therapy is unlikely and in order to achieve eradication, alternative treatment options are required. Stem cell transplantation has been considered previously to effect the clinical course of HIV-infection but in practice eradication or virus control was not achievable. However, modifications of stem cell transplantation using natural or artificial resistant cell sources, combination with new techniques of gene editing or generating cytotoxic anti HIV effector cells have stimulated this field of HIV cell therapy substantially. Here, we look back on 30 years of stem cell therapy in HIV patients and discuss most recent developments in this direction.

Hematopoietic stem cell transplantation for HIV cure

The apparent cure of an HIV-infected person following hematopoietic stem cell transplantation (HSCT) from an allogeneic donor homozygous for the ccr5Δ32 mutation has stimulated the search for strategies to eradicate HIV or to induce long-term remission without requiring ongoing antiretroviral therapy. A variety of approaches, including allogeneic HSCT from CCR5-deficient donors and autologous transplantation of genetically modified hematopoietic stem cells, are currently under investigation. This Review covers the experience with HSCT in HIV infection to date and provides a survey of ongoing work in the field. The challenges of developing HSCT for HIV cure in the context of safe, effective, and convenient once-daily antiretroviral therapy are also discussed.

Safety and Efficacy of Combination Antiretroviral Therapy in Human Immunodeficiency Virus-Infected Adults Undergoing Autologous or Allogeneic Hematopoietic Cell Transplantation for Hematologic Malignancies

The ability to continue combination antiretroviral therapy (cART) in human immunodeficiency virus (HIV)-infected patients undergoing hematopoietic cell transplantation (HCT) for treatment of hematologic malignancies is likely a critical factor in preventing the establishment of an HIV reservoir in transplanted stem cells. Thus, we studied the feasibility of continued antiretroviral therapy in our HIV-infected patients undergoing autologous or allogeneic transplantation. All HIV-infected adults undergoing HCT for hematologic malignancy at Fred Hutchinson Cancer Research Center between 2006 and 2014 were included; most were enrolled in a prospective clinical study to monitor HIV reservoirs after transplantation (NCT00968630 and NCT00112593). Non-nucleotide reverse transcriptase inhibitor or integrase-strand inhibitor-anchored antiretroviral therapy regimens were continued or selected before HCT by infectious disease physicians. Plasma HIV RNA was measured every other day for the first 2 weeks after transplantation and then every 2 weeks. Missed doses of cART and reasons for changing the cART regimen during the post-transplantation hospitalization were documented through review of inpatient pharmacy records. Seven autologous and 8 allogeneic transplantations were performed. In 9 transplantations, the cART regimen was not altered after HCT and no doses were missed. In 2 patients who required alterations in their cART regimen because of development of acute renal failure (n = 1) and small bowel obstruction (n = 1) after HCT, enfuvirtide was used as a bridging component of the regimen. Plasma HIV RNA remained suppressed during the first 28 days in 12 of 15 transplantations, and no patients had a plasma HIV RNA >1000 copies/mL during long-term follow up. Non-nucleotide reverse transcriptase inhibitor- and integrase-strand inhibitor-based cART are safe and effective in HIV-infected persons during the peri-HCT period. Most patients undergoing HCT were able to continue cART without missed doses. Sustained HIV viremia and emergence of resistance were not detected.

HIV and Stem Cell Transplantation

In human immunodeficiency virus (HIV)-infected persons, the incidence of hematologic malignancies, including leukemia and lymphoma, is increased despite the use of successful antiretroviral therapy. Hematopoietic stem cell transplantation (SCT) is emerging as a safe and effective therapy for HIV-infected persons with hematologic malignancies. Management of these patients is complicated by drug-drug interactions involving antiretroviral therapy (ART) that may impact conditioning agent efficacy and metabolism of immunosuppressive medications and potentiate drug toxicities. As such, optimal strategies for ART remain controversial. We discuss recent advances, controversies, and future directions related to SCT in HIV-infected persons, including the investigation of allogeneic SCT as a strategy for HIV cure.

Genetic modification of hematopoietic stem cells as a therapy for HIV/AIDS

The combination of genetic modification and hematopoietic stem cell (HSC) transplantation may provide the necessary means to develop an alternative treatment option to conventional antiretroviral therapy. As HSCs give rise to all hematopoietic cell types susceptible to HIV infection, modification of HSCs is an ideal strategy for the development of infection-resistant immune cell populations. Although promising results have been obtained in multiple animal models, additional evidence is needed to convincingly demonstrate the feasibility of this approach as a treatment of HIV-1 infected patients. Here, we review the potential of HSC transplantation and the recently identified limitations of this approach. Using the Berlin Patient as a model for a functional cure, we contrast the confines of autologous versus allogeneic transplantation. Finally, we suggest that although autologous, gene-modified HSC-transplantation may significantly reduce plasma viremia, reaching the lower detection limits currently obtainable through daily HAART will remain a challenging endeavor that will require innovative combinatorial therapies.

Novel cell and gene therapies for HIV

Highly active antiretroviral therapy dramatically improves survival in HIV-infected patients. However, persistence of HIV in reservoirs has necessitated lifelong treatment that can be complicated by cumulative toxicities, incomplete immune restoration, and the emergence of drug-resistant escape mutants. Cell and gene therapies offer the promise of preventing progressive HIV infection by interfering with HIV replication in the absence of chronic antiviral therapy. Individuals homozygous for a deletion in the CCR5 gene (CCR5Δ32) are largely resistant to infection from R5-topic HIV-1 strains, which are most commonly transmitted. A recent report that an HIV-infected patient with relapsed acute myelogenous leukemia was effectively cured from HIV infection after transplantation of hematopoietic stem/progenitor cells (HSC) from a CCR5Δ32 homozygous donor has generated renewed interest in developing treatment strategies that target viral reservoirs and generate HIV resistance in a patient's own cells. Although the development of cell-based and gene transfer therapies has been slow, progress in a number of areas is evident. Advances in the fields of gene-targeting strategies, T-cell-based approaches, and HSCs have been encouraging, and a series of ongoing and planned trials to establish proof of concept for strategies that could lead to successful cell and gene therapies for HIV are under way. The eventual goal of these studies is to eliminate latent viral reservoirs and the need for lifelong antiretroviral therapy.

Allogeneic haematopoietic stem cell transplantation in patients with human immunodeficiency virus: the experiences of more than 25 years

For treatment of several malignancies, transplantation of allogeneic haematopoietic stem cells (HSCT) derived from bone marrow or peripheral blood has been used as a therapeutic procedure for decades. In the past, HSCT has been suggested as a treatment option for infection with the human immunodeficiency virus type 1 (HIV-1), but these attempts were mostly unsuccessful. Today, after the introduction of an active anti-retroviral therapy, the lifetime expectancy of HIV-infected patients has improved substantially, but nevertheless the incidence rate of malignancies in these patients has increased considerably. Therefore, it can be assumed that there will be a rising necessity for HIV-1-infected patients with malignancies for allogeneic HSCT. At the same time, there is increasing interest in treatment methods which might target the HIV-1 reservoir more effectively, and the question has been raised as to whether allogeneic HSCT could be linked to such strategies. In this paper the data of more than 25 years experience with allogeneic HSCT in patients with HIV-1 are reviewed and analysed.

AIDS-related lymphoproliferative disease

Not long after the recognition of HIV as the causative agent of AIDS, it was evident that individuals infected with HIV developed lymphoma at a greater rate than the population at large. Approximately two thirds of AIDS-related lymphoma (ARL) cases are categorized as diffuse large B-cell type, with Burkitt lymphomas comprising 25% and other histologies a much smaller proportion. Typically, these individuals have presented with advanced extranodal disease and CD4+ lymphocyte counts of less than 200/mm3. Recent clinical trials have demonstrated a better outcome with chemotherapy for ARL since the introduction of combination antiretroviral treatment, termed highly active antiretroviral therapy (HAART). For patients with relapses, solid evidence points to the safety and utility of hematopoietic-cell transplantation as a salvage modality. Coinfection with other viruses such as Epstein-Barr virus and Kaposi sarcoma-associated herpesvirus have led to the genesis of previously rare or unrecognized lymphoma subtypes such as plasmablastic and primary effusion lymphomas. The immunosuppressive impact of treatment for patients with ARL receiving chemotherapy with HAART appears transient and opportunistic infections have become less problematic than prior to HAART. Significant progress has been made in the understanding and management of ARL but outcomes still remain inferior compared to those achieved in HIV- individuals.

AIDS-related malignancies

Immunodeficiency alters the risk of cancer. Specific types of immune dysfunction are associated with different tumor risks, but most tumors are related to oncogenic viruses. In acquired immunodeficiency due to the human immunodeficiency virus (HIV), HIV itself rarely directly causes cancer; rather, it provides the immunologic background against which other viruses can escape immune control and induce tumors. The most common malignancies are Kaposi's sarcoma and non-Hodgkin's lymphoma. This chapter discusses the pathophysiologic background of these tumors, how they have been affected by the use of anti-HIV medications, and their clinical management.

Bone marrow transplantation for nonmalignant diseases

Bone marrow transplantation (BMT) has emerged as a major therapeutic option for a number of nonmalignant disorders affecting the bone marrow and leading to clinical manifestations most likely affecting distant organs. Disorders such as autoimmune diseases, metabolic disorders, hemoglobinopathies, immunodeficiencies, and others have been the target of high-dose therapy and autologous or allogeneic bone marrow, stem cell, or cord blood transplantation. Successful results have been reported in a large number of these disorders. In most instances the goal of transplantation is to provide sufficient degree of marrow engraftment to allow long-term amelioration of disease phenotype. For many of these disorders, early diagnosis is crucial in achieving the desired results as transplantation becomes difficult when significant end-organ damage sets in. Major unsolved problems, including toxicity of conditioning regimens, graft-versus-host disease, and donor availability, need to be addressed. We attempt to provide a comprehensive review of BMT and discuss unique features of this modality for treatment of nonmalignant disorders.

Eliminating human immunodeficiency virus (HIV) from infected individuals and cells: is it possible?

The literature from 1984 to 1991 has been searched for reports of patients who have eliminated human immunodeficiency virus (HIV) from their system. While such reports are scarce, it appears that a small number of HIV-positive patients have reverted to a negative state either spontaneously or following radical immunosuppressive regimens for neoplastic disease. Although no carefully planned animal experiments or clinical trials have been reported, it would appear that bone marrow ablation and replacement may eliminate HIV from healthy, asymptomatic HIV-positive individuals. Although much of the clinical experience to date suggests that radical immunosuppression is not indicated in advanced AIDS patients in whom the virus has likely spread beyond the immune system, such cases do not represent evidence that immunosuppression is not indicated in healthy, HIV-positive individuals.

Severe combined immune deficiency presenting with cyclic hematopoiesis

At age 2 months a male infant presented with a cyclic clinical syndrome every 14-21 days that included pharyngeal aphthous ulcers, high fever, lymphadenopathy, pallor, and malaise. Serial blood studies indicated cycling of all blood cell elements, compatible with a diagnosis of cyclic hematopoiesis (CH). He also manifested a progressively severe immune deficiency, not described before in human CH. When first studied at age 5 months, he was hypogammaglobulinaemic with normal B lymphocyte numbers. By 6.5 months, he was agammaglobulinaemic. At age 8 months, he developed severe pneumocystis carinii pneumonia, and studies showed a state of severe combined immune deficiency. The patient received a bone marrow transplant from his HLA-identical sister with no preconditioning therapy. Subsequently, normal immune function developed and the cyclic hematopoiesis resolved. The majority of lymphocytes is of donor origin. Persistence of erythrocytes and neutrophils of recipient origin suggests that the hematopoietic stem cells were not abnormal. We speculate that this patient had a primary deficiency of a differentiation factor affecting maturation of lymphoid and myeloid progenitor cells.

Acquired immunodeficiency syndrome (AIDS)

The Acquired Immunodeficiency Syndrome (AIDS), caused by the human immunodeficiency virus (HIV), also called the human T-lymphotropic virus type III/lymphadenopathy-associated virus [HTLV-III/LAV], has affected over 23,000 people; more than half of those with the disease have died. The actual case fatality rate approaches 100%. AIDS affects all groups and classes of people, although some are at special risk. Distribution of the disease is worldwide. The illness' effects on the body are widespread; of special interest are the ophthalmologic manifestations. The eye may be infected by various viruses (cytomegalovirus, varicella-zoster virus, herpes simplex virus or HIV itself), toxoplasma gondii, candida sp, cryptococcus neoformans, M. tuberculosis, or M. avium-intracellulare. Kaposi's sarcoma may affect the eye as well. Retinal vascular abnormalities (e.g., cotton-wool spots, vasculitis) are not uncommon in AIDS. The syndrome may present with neuro-ophthalmologic manifestations. No effective treatment for the illness is currently available, although several hold promise and there is hope for an AIDS vaccine. Prevention of infection through reduction of risks appears to be the only defense against AIDS at this time.

Management of infectious and immunological complications of acquired immunodeficiency syndrome (AIDS). Current and future prospects

AIDS is caused by a newly recognised virus (human immunodeficiency virus; HIV) which induces a profound defect in cellular immune function associated with increased susceptibility to opportunistic infections and certain malignancies. The clinical presentation of HIV ranges from asymptomatic infection to severe immunodeficiency manifesting as severe life-threatening infectious diseases or malignancies. While major research efforts are being directed toward development of vaccine and discovery of effective antiretroviral drugs, clinicians are faced with AIDS patients with multiple and complicated medical problems including opportunistic infections and certain malignancies. Currently, efforts are directed toward early diagnosis, treatment, and prevention of recurrence of these opportunistic infections. The current approaches are reviewed in this article. Major recent developments in AIDS research include the isolation of the HIV on culture and the availability of the antibody test. Aside from vaccine and antiretroviral drugs, other measures that may be of benefit in the treatment of AIDS patients are immunological enhancement and reconstitution. Several studies are underway to evaluate antiviral agents in the treatment of HIV infection. Those undergoing clinical trial include suramin, ribavirin, antimoniotungstate, phosphonoformate and azidothymidine. Immune enhancers that have been used include alpha- and gamma-interferon and interleukin-2. HLA-matched lymphocyte transfusions and bone marrow transplantations have been used alone and in combination to replace the AIDS patient's defective immune system.

Effect of azimexon therapy on host defense parameters and disease-associated symptoms in the acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC)

Azimexon, a 2-cyan-aziridinyl immune modulator, was given at a dose of 250 mg/m2/day for 10 days IV to 12 patients with AIDS and 16 with AIDS related complex (ARC). A decrease in total number of AIDS related symptoms from 43 to 24 and in mean number from 2.6 to 1.5 was observed among ARC patients (p less than .01). The most commonly improved symptoms were diarrhea, fatigue, and weight loss with the least frequently improved being lymphadenopathy. The following improvements in immune parameters were observed among ARC patients. DTH to recall antigens improved with an increase in number of positive tests from 35 to 47 and in mean number of positive skin tests from 2.2 on day 0 to 2.9 on day 14 (P less than .05). The geometric mean of the absolute lymphocyte count was 1.395 X 10(3)/microliter on day 0 with a significant increase of 18.0 percent on day 5 (P less than .01) and a 7.7 percent increase on day 21. The geometric mean of the OKT4+ cells on day 0 was 0.250 X 10(3)/microliter with a 33.3 percent increase on day 5 (P less than .07) and a 14.1 percent increase on day 21. T4/T8 ratio increased by 32.7 percent on day 5 (P less than .05) and by 19.4 percent on day 21 from an initial geometric mean of 0.339 X 10(3)/microliter on day 0. The geometric mean of GVH responses increased by 18.2 percent on day 5 (P less than .05) and by 24.0 percent on day 21 (P less than .07) from an initial value of 41.04 mm3. No symptomatic or immunologic improvements were observed among AIDS patients, but rather a significant decrease in mitogenic responses. PHA responses decreased by 70.3 percent on day 5 (P less than .05) and 42.2 percent on day 21 from an initial geometric mean of 4.02 X 10(3) cpm/10(3). Con-A responses decreased by 75.1 percent on day 5 (P less than .05) and increased by 20.3 percent on day 21 from an initial value of 1.14 X 10(3)/10(5) cells. Pretreatment number of absolute OKT4+ cells was the most significant prognostic survival variable. Thus, 8/9 patients with less than 0.10 X 10(3) OKT4+ blood cell/microliter subsequently died as compared to only 1/17 with greater than or equal to 0.10 X 10(3) OKT4+ cells (p less than .001). The only toxic effect of this treatment was mild hemolysis which disappeared upon cessation of treatment.(ABSTRACT TRUNCATED AT 400 WORDS)