Donor lymphocyte infusion for treatment of life-threatening respiratory syncytial virus infection following bone marrow transplantation

Rhinovirus/enterovirus identification by electron microscopy in lower respiratory tract infection in a patient with relapsed myelodysplastic syndrome after allogeneic hematopoietic cell transplantation and donor lymphocyte infusion

Donor lymphocyte infusion (DLI) is a curable treatment option, inducing a graft-versus-tumor effect in patients with relapsed hematological malignancies after allogeneic hematopoietic cell transplantation (allo-HCT). However, not only graft-versus-host disease but also pulmonary complications are problematic adverse events after DLI. Although viral infections can be associated with pulmonary complications after DLI, the mechanism underlying these complications remains unclear. Detecting the causative virus infections after pulmonary complications following DLI is challenging, as invasive examinations, such as bronchoalveolar lavage and lung biopsies, are necessary. Family Picornaviridae, including Human-Rhinovirus (HRV) and Enterovirus (EnV), can induce fatal lower respiratory tract infection (LRTI) in recipients who undergo allo-HCT, which can be underdiagnosed. We encountered a 62-year-old man with relapsed myelodysplastic syndrome 20 days after a second HLA-haplo-identical allo-HCT and 4 DLI procedures who was later found to have HRV and EnV LRTI by postmortem electron microscopy. Despite high-dose immunosuppression, severe hypoxemia did not improve, and he succumbed to respiratory failure. Immunosuppressive therapy for idiopathic pneumonia syndrome after allo-HCT may be effective, but its efficacy for acute respiratory failure after DLI is controversial. Our case indicated that the control of viral replication should be prioritized over that of inflammation in HRV and EnV LRTI after DLI.

Comparing the application of mNGS after combined pneumonia in hematologic patients receiving hematopoietic stem cell transplantation and chemotherapy: A retrospective analysis

Rapid and accurate pathogen identification is essential for timely and effective treatment of pneumonia. Here, we describe the use of metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage (BALF) fluid to identify pathogens in patients with hematologic comorbid respiratory symptoms in a retrospective study with 84 patients. In the transplantation group, 8 cases (19.5%) and 47 cases (97.9%) were positive for BALF by conventional method detection and mNGS detection, respectively, and 6 cases (14.0%) and 41 cases (91.1%) in chemotherapy group, respectively. The detection rate of mNGS in both groups was significantly higher than that of conventional detection methods (all P<0.05). Pseudomonas aeruginosa and Streptococcus pneumoniae were the most common bacterial infections in the transplantation and chemotherapy groups, respectively. Aspergillus was the most common fungal infection in both groups. Human betaherpesvirus 5 (HHV-5), torque teno virus and human betaherpesvirus 7 (HHV-7) were the most common pathogen species in both groups. The most common type of infection in patients in the transplantation and chemotherapy groups was the mixed infection of bacteria-virus. Most patients in the transplantation group had mixed infections based on multiple viruses, with 42 cases of viral infections in the transplantation group and 30 cases of viral infections in the chemotherapy group, which were significantly higher in the transplantation group than in the chemotherapy group (χ2 = 5.766, P=0.016). and the mixed infection of virus-virus in the transplantation group was significantly higher than that in the chemotherapy group (27.1% vs 4.4%, P=0.003). The proportion of death due to pulmonary infection was significantly higher in the transplantation group than in the chemotherapy group (76.9% vs 16.7%, χ2 = 9.077, P=0.003). This study demonstrated the value of mNGS of BALF in improving the diagnosis and prognosis of hematologic comorbid pneumonia, helping patients to obtain timely and effective treatment, and giving guidance on the overall treatment plan for patients, with particular benefit for patients with hematologic chemotherapy comorbid pneumonia.

Advances in Allogeneic Cancer Cell Therapy and Future Perspectives on “Off-the-Shelf” T Cell Therapy Using iPSC Technology and Gene Editing

The concept of allogeneic cell therapy was first presented over 60 years ago with hematopoietic stem cell transplantation. However, complications such as graft versus host disease (GVHD) and regimen-related toxicities remained as major obstacles. To maximize the effect of graft versus leukemia, while minimizing the effect of GVHD, donor lymphocyte infusion was utilized. This idea, which was used against viral infections, postulated that adoptive transfer of virus-specific cytotoxic T lymphocytes could reconstitute specific immunity and eliminate virus infected cells and led to the idea of banking third party cytotoxic T cells (CTLs). T cell exhaustion sometimes became a problem and difficulty arose in creating robust CTLs. However, the introduction of induced pluripotent stem cells (iPSCs) lessens such problems, and by using iPSC technology, unlimited numbers of allogeneic rejuvenated CTLs with robust and proliferative cytotoxic activity can be created. Despite this revolutionary concept, several concerns still exist, such as immunorejection by recipient cells and safety issues of gene editing. In this review, we describe approaches to a feasible “off-the-shelf” therapy that can be distributed rapidly worldwide. We also offer perspectives on the future of allogeneic cell cancer immunotherapy.

Cellular Immunotherapy and the Lung

The new era of cellular immunotherapies has provided state-of-the-art and efficient strategies for the prevention and treatment of cancer and infectious diseases. Cellular immunotherapies are at the forefront of innovative medical care, including adoptive T cell therapies, cancer vaccines, NK cell therapies, and immune checkpoint inhibitors. The focus of this review is on cellular immunotherapies and their application in the lung, as respiratory diseases remain one of the main causes of death worldwide. The ongoing global pandemic has shed a new light on respiratory viruses, with a key area of concern being how to combat and control their infections. The focus of cellular immunotherapies has largely been on treating cancer and has had major successes in the past few years. However, recent preclinical and clinical studies using these immunotherapies for respiratory viral infections demonstrate promising potential. Therefore, in this review we explore the use of multiple cellular immunotherapies in treating viral respiratory infections, along with investigating several routes of administration with an emphasis on inhaled immunotherapies.

Infusion of cytotoxic T lymphocytes for the treatment of viral infections in hematopoetic stem cell transplant patients

PURPOSE OF REVIEW

Allogeneic hematopoietic stem cell transplantation has proven curative for a range of malignant and nonmalignant disorders. However, the clinical success of this therapy is marred by the morbidity associated with viral infections, which are frequent (cytomegalovirus 15.6-28%, adenovirus 3-21%, BK virus 18.5-20.7%) post-transplant. These infections occur as a consequence of transplant conditioning regimens designed to eliminate not only malignant cells but also host immune cells that might interfere with stem cell engraftment. The result is a transient period of immune compromise when hematopoietic stem cell transplant recipients are at risk of infectious complications associated with both latent (cytomegalovirus, Epstein-Barr virus, BK virus, human herpes virus 6, herpes simplex virus, varicella-zoster virus) and community-acquired viruses including adenovirus, respiratory syncytial virus, and parainfluenza virus.

RECENT FINDINGS

Current standard of care for many of these infections involves pharmacologic agents, which are often ineffective and associated with side effects including nephrotoxicity and hepatotoxicity. Ultimately, because these agents do not address the underlying immune compromise, viral rebound often occurs. Thus, a number of groups have explored the clinical potential of adoptively transferred virus-specific T cells (VSTs) as an approach to prevent/treat virus-associated complications.

SUMMARY

The current review will highlight recent publications showcasing VST manufacturing technologies and clinical experience with such cells.

Respiratory Virus Infections in Hematopoietic Cell Transplant Recipients

Highly immunocompromised pediatric and adult hematopoietic cell transplant (HCT) recipients frequently experience respiratory infections caused by viruses that are less virulent in immunocompetent individuals. Most of these infections, with the exception of rhinovirus as well as adenovirus and parainfluenza virus in tropical areas, are seasonal variable and occur before and after HCT. Infectious disease management includes sampling of respiratory specimens from nasopharyngeal washes or swabs as well as sputum and tracheal or tracheobronchial lavages. These are subjected to improved diagnostic tools including multiplex PCR assays that are routinely used allowing for expedient detection of all respiratory viruses. Disease progression along with high mortality is frequently associated with respiratory syncytial virus, parainfluenza virus, influenza virus, and metapneumovirus infections. In this review, we discuss clinical findings and the appropriate use of diagnostic measures. Additionally, we also discuss treatment options and suggest new drug formulations that might prove useful in treating respiratory viral infections. Finally, we shed light on the role of the state of immune reconstitution and on the use of immunosuppressive drugs on the outcome of infection.

Donor lymphocyte infusion after allogeneic hematopoietic stem cell transplantation

Donor lymphocyte infusion, a rescue therapy after hematopoietic stem cell transplantation, has been increasingly adopted, as modalities of stem cell transplantation have widened. First described as donor lymphocyte transfusion or cell therapy, it consists of infusion of donor lymphocytes, collected in steady state or after growth factor enhancement. As in literature the most used name is donor lymphocyte infusion, we'll adopt it here. Its most striking efficacy is observed in patients with chronic myelogenous leukemia, who relapsed after allogeneic stem cells transplantation. However, graft-versus-host disease, its main complication, may still hamper its feasibility.

Preventing stem cell transplantation-associated viral infections using T-cell therapy

Hematopoietic stem cell transplantation is the treatment of choice for many hematologic malignancies and genetic diseases. However, viral infections continue to account for substantial post-transplant morbidity and mortality. While antiviral drugs are available against some viruses, they are associated with significant side effects and are frequently ineffective. This review focuses on the immunotherapeutic strategies that have been used to prevent and treat infections over the past 20 years and outlines different refinements that have been introduced with the goal of moving this therapy beyond specialized academic centers.

Adoptive therapy with donor lymphocyte infusion after allogenic hematopoietic SCT in pediatric patients

The aim of this study was to analyse the experience of Polish Pediatric Group for Hematopoietic Stem Cell Transplantation in respect to donor lymphocyte infusion procedure. The study included 51 pediatric patients with malignant (45) and non-malignant (6) diseases treated with DLI in the period 1993-2012. The indications for DLI were as follows: (1) increasing recipient chimerism after non-ablative hematopoietic SCT (18 patients); (2) immunomodulation after a reduced intensity conditioning regimen (2 patients); (3) increase in minimal residual disease detection (3 patients); and (4) relapse (28 patients). DLI was carried out at a median of 6 (0.5-79) months after SCT. DLI was administered as either a single-dose (in 19 cases) or in escalating-dose regimens (in 32 cases). The median total dose of CD3-positive T cells was 28.0 (0.1-730.0) × 10(6)/kg body weight. The time for assessment of DLI efficacy ranged from 0 to 70 (median 3) months. At evaluation, 18 patients experienced CR, 3 achieved PR, 19 showed relapse and 11 rejected the graft. DLI was found to be effective in 39% of cases. Complications of the procedure occurred in 18 patients; of these, 2 died. To sum up DLI shows efficacy in a significant percentage of children. Mortality related to the therapy adverse effects is low. However, this method requires standardization.

Cellular therapy following allogeneic stem-cell transplantation

Allogeneic hematopoietic stem-cell transplantation (HSCT) is the most effective approach for many patients with hematologic malignancies. Unfortunately, relapse remains the most common cause of death after allogeneic HSCT, and the prognosis of relapsed disease is poor for most patients. Induction of a graft-versus-leukemia (GVL), or graft-versus-tumor, effect through the use of donor leukocyte infusion (DLI), or donor lymphocyte infusion, has been remarkably successful for relapsed chronic myelogenous leukemia. Unfortunately, response to DLI in other hematologic malignancies is much less common and depends on many factors including histology, pace and extent of relapse, and time from HSCT to relapse. Furthermore, graft-versus-host disease (GVHD) is common after DLI and often limits successful immunotherapy. Ultimately, manipulations to minimize GVHD while preserving or enhancing GVL are necessary to improve outcomes for relapse after allogeneic HSCT.

Graft-versus-host disease after donor leukocyte infusions: presentation and management

Donor leukocyte infusion (DLI) is used after both myeloablative and non-myeloablative stem-cell transplantation to treat and prevent relapse, to establish full donor chimerism, and to treat and prevent infections. The major treatment-related complication of DLI is graft-versus-host disease (GVHD). The presentation and treatment of GVHD after DLI is similar to its presentation and treatment after stem-cell transplantation, with some notable exceptions. While GVHD and graft-versus-tumor (GVT) effects are highly correlated after DLI, some patients experience remission without GVHD. Studies to define tumor-specific target antigens and GVT effector cells, as well as strategies of donor T-cell manipulation and optimization of DLI dose and schedule, may ultimately lead to the consistent ability to separate GVHD from GVT activity, improvement in the safety and specificity of DLI, and enhancement of the anti-tumor activity of donor T cells.

A case of immune recovery vitritis induced by donor leukocyte infusion for the treatment of cytomegalovirus retinitis

Donor leukocyte infusion (DLI) has been successfully used for some life-threatening viral infections after stem cell transplantation (SCT). We describe here the first case of DLI treatment for cytomegalovirus (CMV) retinitis. A 49-year-old female patient with AML, M1 underwent SCT with a reduced-intensity conditioning regimen from HLA-haploidentical son. On day +140, the patient developed CMV retinitis of her left eye despite the continuing antiviral therapy. DLI at a dose of 1 x 10(5) CD3+ cells/kg was added to ganciclovir and foscarnet therapy. Eighteen days after the DLI, the funduscopic findings revealed improvement of the retinitis and the development of vitreous inflammation. Simultaneously, the number of CD4+ cells in the peripheral blood rapidly increased. Thus, we consider it likely that DLI induced a local immune response against CMV antigens, which resulted in the immune recovery vitritis. This case suggested the potentiality of DLI for the treatment of CMV retinitis.

Antiviral immunity and T-regulatory cell function are retained after selective alloreactive T-cell depletion in both the HLA-identical and HLA-mismatched settings

Nonselective T-cell depletion reduces the incidence of severe graft-versus-host disease after allogeneic hematopoietic stem cell transplantation, but the cost is delayed and disordered antigen-specific immune reconstitution and increased infection. We use a method of selective depletion of alloreactive T cells expressing the activation marker CD69 after coculture with stimulator cells in a modified or standard mixed lymphocyte reaction. The technique has been shown to reduce alloreactivity while retaining third-party responses in vitro and, in a mismatched murine model, led to donor T-cell engraftment with a virtual absence of graft-versus-host disease and increased survival. We show in a human HLA-mismatched and unrelated HLA-identical setting that this technique retains >80% of specific cellular antiviral activity by cytomegalovirus-tetramer analysis and cytomegalovirus/Epstein-Barr virus peptide-stimulated interferon-gamma ELISpot assay. Furthermore, CD4(+) CD25(+) T-regulatory cells are not removed by this method of selective allodepletion and retain their function in suppressing allogeneic proliferative responses. Preservation of antiviral cytotoxic T lymphocytes in selectively allodepleted stem cell grafts would lead to improved antiviral immunity after transplantation. The retention of immunosuppressive CD4(+) CD25(+) T-regulatory cells could lead to more ordered immune reconstitution and further suppress alloreactive responses after transplantation.

Adoptive immunotherapy for posttransplantation viral infections

Viral diseases are a major cause of morbidity and mortality after hemopoietic stem cell transplantation. Because viral complications in these patients are clearly associated with the lack of recovery of virus-specific cellular immune responses, reconstitution of the host with in vitro expanded cytotoxic T lymphocytes is a potential approach to prevent and treat these diseases. Initial clinical studies of cytomegalovirus and Epstein-Barr virus in human stem cell transplant patients have shown that adoptively transferred donor-derived virus-specific T cells may restore protective immunity and control established infections. Preclinical studies are evaluating this approach for other viruses while strategies for generating T cells specific for multiple viruses to provide broader protection are being evaluated in clinical trials. The use of genetically modified T cells or the use of newer suicide genes may result in improved safety and efficacy.

Infectious risks and outcomes after stem cell transplantation: are nonmyeloablative transplants changing the picture?

PURPOSE OF REVIEW

Opportunistic infections contribute to morbidity and mortality after myeloablative allogeneic stem cell transplantation. The development of nonmyeloablative or toxicity-reduced conditioning regimens for allogeneic hematopoietic stem cell transplantation might change this picture significantly. These regimens are in general highly immunosuppressive, but effects on myelopoiesis and mucosal toxicities are usually reduced compared with myeloablative hematopoietic stem cell transplantation conditioning regimens. This review summarizes the infectious risks associated with each type of hematopoietic stem cell transplantation conditioning regimen, and presents the results of early clinical studies.

RECENT FINDINGS

Although the data are preliminary, the results of recent studies suggest that nonmyeloablative conditioning regimens may decrease the risks of bacterial infections associated with mucosal damage and persistent neutropenia; however, risks for late viral and fungal infections persist during severe graft versus host disease. Results of several case reports and series emphasize that therapeutic outcomes of infections may be improved in patients who receive nonmyeloablative conditioning regimens.

SUMMARY

Infectious risks and outcomes after hematopoietic stem cell transplantation appear to be in evolution given the introduction of alternative, nonmyeloablative conditioning regimens. Although infections remain a prominent cause of transplant-related mortality, the timing and types of infections may differ. Further studies are necessary to define appropriate preventative strategies, and to determine whether patients with ongoing infections might benefit from nonmyeloablative hematopoietic stem cell transplantation.

Viral infections in immunocompromised patients: what's new with respiratory viruses?

PURPOSE OF REVIEW

The leading cause of death in solid organ and hematopoietic stem cell transplant recipients is infection. The respiratory viruses, particularly respiratory syncytial virus, influenza, parainfluenza, adenovirus, and picornaviruses, are increasingly recognized as significant pathogens in these populations.

RECENT FINDINGS

Respiratory syncytial virus has again been found to be the most common of the respiratory viruses causing severe infections in transplant recipients. Advances in prevention, particularly with regard to infection control practices, and to lesser extent treatment have had a substantial impact on the frequency and outcomes of this infection. New studies have clarified the impact of influenza in the hematopoietic stem cell transplant recipients and have provided evidence to support the use of M2 and neuraminidase inhibitors for early treatment. The epidemiology of parainfluenza and adenovirus in transplant recipients has been clarified, although therapeutic modalities are still limited and understudied. New antiviral medications may bring improved outcomes of picornavirus infections in this population. Finally, a new virus, the human metapneumovirus, has recently been described and may be a significant respiratory pathogen in immunocompromised transplant recipients.

SUMMARY

Studies published over the past year have documented a new respiratory pathogen. They have also resulted in improved understanding of the epidemiology of all of the respiratory virus pathogens, and have contributed to improve management of respiratory syncytial virus and influenza infection in hematopoietic stem cell transplant and solid organ transplant recipients.

Donor lymphocyte infusions to treat hematologic malignancies in relapse after allogeneic blood or marrow transplantation

BACKGROUND

Patients with hematologic malignancies in relapse after allogeneic bone marrow transplantation can be treated by infusing leukocytes from the original stem cell donor.

METHODS

The published literature on donor lymphocyte infusion (DLI) was reviewed.

RESULTS

DLI induces complete remissions in the majority of patients with chronic myeloid leukemia (CML) in early-stage relapse and in less than 30% of patients with relapsed acute leukemia, myelodysplasia, and multiple myeloma. DLI-induced remissions of chronic phase CML are durable, but as many as half of patients with other diseases ultimately relapse. Complications of DLI include acute and chronic graft-vs-host disease (GVHD) and aplasia, which induce profound immunosuppression and susceptibility to opportunistic infections. There is a strong correlation of GVHD and disease response.

CONCLUSIONS

Novel methods of augmenting the antitumor efficacy of DLI and of dissociating the graft-vs-leukemia effect from GVHD are needed. These studies will require an improved understanding of the cellular and molecular mechanisms of alloreactivity and the development of novel agents to control the nature and intensity of the alloimmune response.

Respiratory virus infections in adult T cell-depleted transplant recipients: the role of cellular immunity

BACKGROUND

Little is known about the role of cellular immunity in respiratory virus infections after bone marrow transplantation.

METHODS

Forty allograft recipients T-cell depleted with Campath antibodies were evaluated for respiratory virus infections in an active surveillance program with early initiation of antiviral therapy.

RESULTS

Eighteen episodes of respiratory virus infection were detected in nine patients (22%) at a median of 95 days, with lower respiratory involvement in 44%. Fourteen episodes were treated with antiviral therapy for 7 to 46 days, with 11% mortality. Respiratory virus infections were more common in patients receiving Campath 100 mg in vivo, but delayed CD4+ recovery was the most significant risk factor.

CONCLUSIONS

Respiratory virus infections are common and often recurrent in patients with severe CD4+ T lymphopenia. However, the mortality was low, which may have been due to early institution of antiviral treatment or reduced inflammatory damage to the lungs due to severe lymphopenia.

Severe infections after bone marrow transplantation

Bone marrow transplantation and stem cell transplantation have become standard therapies offering potential cures for a number of hematologic malignancies and immunologic disorders. Severe infection remains a life threatening complication after transplantation, contributes significantly to morbidity, and may necessitate admission to the ICU. It is estimated that between 20 and 40% of patients receiving bone marrow transplant will require ICU admission in the initial posttransplantation phase. Historically, survival rates after admission to the ICU are dismal, particularly if mechanical ventilation is required for respiratory failure. Other organ involvement worsens the prognosis still further and has led to proposals for rationing or restricting access to critical care units and supportive measures. Recent studies have reported small but significant improvements in outcome after critical illness. Whether this improvement is a result of changes in levels of supportive care or a more defined patient selection is uncertain. Moreover, risk factors identifying patients who will benefit most from intensive support are poorly defined. However, it is generally accepted that respiratory failure requiring invasive mechanical ventilation is associated with a poor prognosis in this patient group. Early involvement of intensivists in the management of critical illness in transplant recipients is likely to continue to improve survival in this group of patients.