Improving cytomegalovirus-specific T cell reconstitution after haploidentical stem cell transplantation. J Immunol Res. 2014;2014:631951. [PMID: 24864269 PMCID: PMC4017791 DOI: 10.1155/2014/631951]

The frequencies of lymphocyte subsets on "day 30″ correlate with the clinical outcome of pediatric hematopoietic stem cell transplantation

We aimed to determine the relationship between lymphocyte subsets on day 30 (D30) and prognosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children. We retrospectively examined the clinical outcomes and lymphocyte subsets on D30 after allo-HSCT in 115 pediatric patients at the Children's Hospital of Soochow University between January 2016 and June 2019. Measurements were performed using flow cytometry on D30. Lymphocyte subsets were compared among the umbilical cord blood (UCB) (n = 22), HLA-matched sibling donor (MSD) (n = 14), haploidentical donor transplantation (HID) (n = 57), and unrelated donor transplantation (UD) (n = 22) groups. The relationships between the frequencies and counts of lymphocyte subsets and clinical outcomes were analyzed. T and B cell counts were the highest in the MSD group compared to the other groups, and natural killer cell counts were the highest in the UCB group. Lymphocyte subsets on D30 after allo-HSCT were correlated with the occurrence of acute (aGVHD) and chronic graft versus host disease (cGVHD). A high frequency of B cells (≥4.65%) was associated with the development of severe aGVHD. High frequencies of CD4⁺T (≥10.25%) were correlated with extensive cGVHD. Moreover, a high frequency of CD4⁺T cells (≥9.80%) was correlated with GVHD-free and failure-free survival (GFFS) after allo-HSCT. However, on D30, there were no statistically significant correlations between viral infections and lymphocyte subsets. The frequencies of lymphocyte subsets on D30 after allo-HSCT are good indicators of prognosis after allo-HSCT in children.

Donor-derived cytomegalovirus-cytotoxic T lymphocytes and leflunomide successfully control refractory cytomegalovirus infections and disease of multiple sites after allogeneic-hematopoietic stem cell transplantation: A case report

Drug-resistant cytomegalovirus (CMV) infection after hematopoietic stem cell transplantation (HSCT) often leads to morbidity and mortality. Several studies have shown that CMV-cytotoxic T lymphocytes (CTLs) can overcome drug-resistant CMV infection, but still many questions remain unanswered. Here, we present a case of refractory CMV infection after allogeneic HSCT (allo-HSCT). Donor-derived CMV-CTLs failed to eliminate the virus in unique peripheral blood on the first application, when 70 mg methylprednisolone (MP) was taken per day. After a second attempt with a combination of 8 mg MP with leflunomide, a complete and persisting clearance of all involved sites, including peripheral blood, urinary system, leptomeninges, and retina, was achieved. To summarize, intravenous infusion of CTLs can eliminate CMV in the oculi and central nervous system (CNS), and a low dosage of 8 mg MP has no interaction with CMV-CTLs.

CMV Infection and CMV-Specific Immune Reconstitution Following Haploidentical Stem Cell Transplantation: An Update

Haploidentical stem cell transplantation (haploSCT) has advanced to a common procedure for treating patients with hematological malignancies and immunodeficiency diseases. However, cure is seriously hampered by cytomegalovirus (CMV) infections and delayed immune reconstitution for the majority of haploidentical transplant recipients compared to HLA-matched stem cell transplantation. Three major approaches, including in vivo T-cell depletion (TCD) using antithymocyte globulin for haploSCT (in vivo TCD-haploSCT), ex vivo TCD using CD34 + positive selection for haploSCT (ex vivo TCD-haploSCT), and T-cell replete haploSCT using posttransplant cyclophosphamide (PTCy-haploSCT), are currently used worldwide. We provide an update on CMV infection and CMV-specific immune recovery in this fast-evolving field. The progress made in cellular immunotherapy of CMV infection after haploSCT is also addressed. Groundwork has been prepared for the creation of personalized avenues to enhance immune reconstitution and decrease the incidence of CMV infection after haploSCT.

T cell immunobiology and cytokine storm of COVID-19

2019 coronavirus disease (COVID-19) presents as a newly recognized pneumonia and could rapidly progress into acute respiratory distress syndrome which has brought about a global pandemic. Until now, no curative therapy has been strongly recommended for COVID-19 except for personalized supportive care. T cells and virus-specific T cells are essential to protect against virus infection, including COVID-19. Delayed immune reconstitution (IR) and cytokine storm (CS) remain serious obstacles for the cure of COVID-19. Most COVID-19 patients, especially among elderly patients, had marked lymphopenia and increased neutrophils, but T cell counts in severe COVID-19 patients surviving the disease gradually restored later. Elevated pro-inflammatory cytokines, particularly IL-6, IL-10, IL-2 and IL-17, and exhausted T cells are found in peripheral blood and the lungs. It suggests that Thymosin α1 and adoptive COVID-19-specific T cells could improve IR, while convalescent plasma, IL-6 blockade, mesenchymal stem cells and corticosteroids could suppress CS. More clinical studies in this field worldwide are urgently warranted to pave the way for therapy of COVID-19 in the future.

Generation of high-affinity CMV-specific T cells for adoptive immunotherapy using IL-2, IL-15, and IL-21

Cytomegalovirus (CMV) infection remains a life-threatening condition in individuals with a suppressed immune system. CMV may also represent a clinically relevant target for immune responses in CMV-positive malignancies. We established a protocol to expand CMV-specific T cells (CMV-T) using peripheral blood mononuclear cells (PBMCs). PBMCs from 16 HLA-A*0201 donors were cultured with a cytokine cocktail comprising IL-2/IL-15/IL-21 along with overlapping peptides from CMV-pp65. Ten days later, T cells were stimulated with anti-CD3 (OKT3) and irradiated autologous PBMCs. CMV-T were detected by HLA-A*0201 CMV-pp65_NLVPMVATV wild type and q226a mutant tetramers (for high-affinity T cells), intracellular cytokine staining, a CD107a mobilization assays as well as IFN-γ and TNF-α production in cell culture supernatants. We reliably obtained 50.25 ± 27.27% of CD8+ and 22.08 ± 21.83% of CD4+ T cells post-CMV-pp65 stimulation of PBMCs with a Th1-polarized phenotype and decreased Th2/Th17 responses. Most CD3 + CD8 + tetramer+ T cells were effector-memory cells, particularly among high-affinity CMV-T (q226a CMV-tetramer+). High-affinity CMV-T cells, compared to WT-tetramer+ cells, expressed higher IL-21R and lower FasL post-stimulation with CMV-pp65. The IL-2/IL-15/IL-21 cocktail also promoted CCR6 and CXCR3 expression necessary for T-cell migration into tissues. We have optimized methods for generating high-affinity CMV-specific T cells that can be used for adoptive cellular therapy in clinical practice.

Bone marrow mesenchymal stem cells combined with Sox2 increase the functional recovery in rat with traumatic brain injury

Background

About 10 million individuals suffer from traumatic brain injury (TBI) each year in the world, which is one of the most serious neurological disorders. The morbidity of TBI is 55.5~6.1/100,000 in China, which takes more costing in the therapy, and the outcome of that is not well. Therefore, we expect to find new methods to treat TBI and improve the outcomes of TBI. In the previous studies reviewed, we found that stem cell transplantation may hold promising potential for modifying motor dysfunction induced by TBI.

Methods

Twenty-six adult SD rats were involved in our study. Two adult SD rats were used as donors of bone marrow stem cells (BMSCs), and the other adult SD rats were divided into four groups randomly, which were used to establish the TBI models. BMSCs were transduced with lentivirous-Sox2, and we try to examine the effects of Sox2 on the differentiation of BMSCs.

Establishment of rat TBI model

Rats were anesthetized using pentobarbital sodium (at a concentration of 1.5% and a dose of 40 mg/kg) and fixed under the stereotaxic device. A 1.0-cm craniotomy was performed lateral to the sagittal suture. The skullcap was carefully removed, and rats were then subjected to TBI using a controlled cortical injury instrument. A standardized parietal contusion was performed using a 20-mg steel rod with a diameter of 4 mm, which dropped from a height of 30 cm. After injury, the incision was sutured, and rats were carefully observed and nursed.

Treatments

Seven days after TBI, rats were divided into four groups and were transplanted with BMSC-Sox2, single BMSC, single Lentivirus-Sox2, and PBS into injured brain, respectively. The motor function was tested using the neurological severity score (NSS).

Results

We found that the ectopic expression of Sox2 enhanced BMSCs to differentiate into neurons. Seven days after TBI, the rats were treated with BMSC-Sox2, BMSC, Sox2, and PBS. Results showed that NSS were 3.352 ± 0.398 in the BMSC-Sox2 group, 4.013 ± 0.495 in the BMSC group, 4.968 ± 0.293 in the Sox2 group, and 6.257 ± 0.361 in the PBS group, suggesting that there were obvious improvements in the neurological function in BMSC-Sox2, BMSC, and Sox2 groups. In addition, the BMSC-Sox2 group had the lowest scores, p < 0.05.

Conclusion

The ectopic expression of Sox2 could enhance BMSCs to differentiate into neurons, and intervention of BMSCs combined with Sox2 transplantation could promote recovery of motor function in rats with TBI.

Immune reconstitution following hematopoietic stem cell transplantation using different stem cell sources

Introduction: Adequate immune reconstitution post-HSCT is crucial for the success of transplantation, and can be affected by both patient- and transplant-related factors. Areas covered: A systematic literature search in PubMed, Scopus, and abstracts of international congresses is performed to investigate immune recovery posttransplant. In this review, we discuss the pattern of immune recovery in the post-transplant period focusing on the impact of stem cell source (bone marrow, peripheral blood stem cells, and cord blood) on immune recovery and HSCT outcome. We examine the impact of serotherapy on immune reconstitution and the need to tailor dosing of serotherapy agents when using different stem cell sources. We discuss new techniques being used particularly with cord blood and haploidentical grafts to improve immune recovery in each scenario. Expert opinion: Cord blood T cells provide a unique CD4+ biased immune reconstitution. Initial studies using targeted serotherapy with cord grafts showed improved immune recovery with limited alloreactivity. Two competing haploidentical approaches have developed in recent years including TCRαβ/CD19 depleted grafts and post-cyclophosphamide haplo-HSCT. Both approaches have comparable survival rates with limited alloreactivity. However, delayed immune reconstitution is still an ongoing problem and could be improved by modified donor lymphocyte infusions from the same haploidentical donor.

Cytomegalovirus infection is associated with AML relapse after allo-HSCT: a meta-analysis of observational studies

Cytomegalovirus (CMV) infection and primary disease relapse remain challenging problems after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We sought to assess the association between CMV infection and disease relapse after transplantation. PubMed, EMBASE, the Cochrane Library, SCI, and Chinese Biomedicine Databases were searched up to July 1, 2018, for all studies that investigate pre-transplant CMV serostatus, CMV replication, and primary disease relapse in allo-HSCT patients with hematologic malignancies. Meta-analysis of 24 eligible cohort studies showed a significantly lower relapse risk after allo-HSCT in patients with CMV replication in acute myeloid leukemia (AML) (HR = 0.64, 95% CI, 0.50-0.83; P < 0.001) subgroup. However, CMV replication was associated with increased non-relapse mortality (NRM) in AML patients (HR = 1.64, 95% CI, 1.46-1.85; P < 0.001), but not associated with overall survival (OS) or graft-versus-host disease for AML patients (P > 0.05). There was no association between pre-transplant CMV serostatus and disease relapse, although D-/R- was associated with better OS in acute leukemia patients (HR = 0.89, 95% CI, 0.83-0.96; P = 0.003). In AML patients, CMV replication may be a protective predictor against disease relapse, although the potential benefit of CMV replication is offset by increased NRM.

The impact of inflationary cytomegalovirus-specific memory T cells on anti-tumour immune responses in patients with cancer

Human cytomegalovirus (CMV) is a ubiquitous, persistent beta herpesvirus. CMV infection contributes to the accumulation of functional antigen-specific CD8⁺ T-cell pools with an effector-memory phenotype and enrichment of these immune cells in peripheral organs. We review here this 'memory T-cell inflation' phenomenon and associated factors including age and sex. 'Collateral damage' due to CMV-directed immune reactivity may occur in later stages of life - arising from CMV-specific immune responses that were beneficial in earlier life. CMV may be considered an age-dependent immunomodulator and a double-edged sword in editing anti-tumour immune responses. Emerging evidence suggests that CMV is highly prevalent in patients with a variety of cancers, particularly glioblastoma. A better understanding of CMV-associated immune responses and its implications for immune senescence, especially in patients with cancer, may aid in the design of more clinically relevant and tailored, personalized treatment regimens. 'Memory T-cell inflation' could be applied in vaccine development strategies to enrich for immune reactivity where long-term immunological memory is needed, e.g. in long-term immune memory formation directed against transformed cells.

Immune Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation

The timely reconstitution and regain of function of a donor-derived immune system is of utmost importance for the recovery and long-term survival of patients after allogeneic hematopoietic stem cell transplantation (HSCT). Of note, new developments such as umbilical cord blood or haploidentical grafts were associated with prolonged immunodeficiency due to delayed immune reconstitution, raising the need for better understanding and enhancing the process of immune reconstitution and finding strategies to further optimize these transplant procedures. Immune reconstitution post-HSCT occurs in several phases, innate immunity being the first to regain function. The slow T cell reconstitution is regarded as primarily responsible for deleterious infections with latent viruses or fungi, occurrence of graft-versus-host disease, and relapse. Here we aim to summarize the major steps of the adaptive immune reconstitution and will discuss the importance of immune balance in patients after HSCT.

Treatment of CMV infection after allogeneic hematopoietic stem cell transplantation

Despite a remarkable reduction in the past decades, cytomegalovirus (CMV) disease in allogeneic hematopoietic stem cell transplant (HSCT) recipients remains a feared complication, still associated with significant morbidity and mortality. Today, first line treatment of CMV infection/reactivation is still based on dated antiviral compounds Ganciclovir (GCV), Foscarnet (FOS) and Cidofovir (CDF) with their burdensome weight of side effects. Maribavir (MBV), Letermovir (LMV) and Brincidofovir (BDF) are three new promising anti-CMV drugs without myelosuppressive properties or renal toxic effects that are under investigation in randomized phase II and III trials. Adoptive T-cell therapy (ATCT) in CMV infection possesses a strong rationale, demonstrated by several proof of concept studies; its feasibility is currently under investigation by clinical trials. ATCT from third-party and naïve donors could meet the needs of HSCT recipients of seronegative donors and cord blood grafts. In selected patients such as recipients of T-cell depleted grafts, ATCT, based on CMV-specific host T-cells reconstitution kinetics, would be of value in the prophylactic and/or preemptive CMV treatment. Vaccine-immunotherapy has the difficult task to reduce the incidence of CMV reactivation/infection in highly immunocompromised HSCT patients. Newer notions on CMV biology may represent the base to flush out the Troll of transplantation.

Cytomegalovirus infection in the bone marrow transplant patient

Cytomegalovirus (CMV) infection is an important contributor to the morbidity and mortality associated with bone marrow transplantation (BMT). Infection may lead to CMV disease involving multiple organs such as pneumonia, gastroenteritis, retinitis, central nervus system involvement and others. CMV seropositivity is an important risk factor and approximately half of BMT recipients will develop clinically significant infection most commonly in the first 100 d post-transplant. The commonly used tests to diagnose CMV infection in these patients include the pp65 antigenemia test and the CMV DNA polymerase chain reaction (PCR) assay. Because of its greater sensitivity and lesser turnaround time, the CMV PCR is nowadays the preferred test and serves as a main guide for pre-emptive therapy. Methods of CMV prevention include use of blood products from seronegative donors or leukodepleted products. Prophylaxis or pre-emptive therapy strategies for CMV prevention may be used post-transplant with the latter becoming more common. The commonly used antivirals for pre-emptive therapy and CMV disease management include intravenous gancyclovir and foscarnet. The role of intravenous immunoglobulin, although used commonly in CMV pneumonia is not clear.

Haploidentical hematopoietic transplantation without T-cell depletion: current status and future perspectives

Human leukocyte antigen (HLA)-haploidentical hematopoietic stem cell transplantation (HLA-haplo HSCT) without T-cell depletion has tremendously progressed over the past 20 years and has become a feasible treatment option for leukemia patients without an HLA-identical sibling donor. Advances in conditioning regimens, graft manipulation, and pharmacological graft-versus-host disease (GVHD) prophylaxis have reduced the risk of fatal graft failure and severe GVHD, two of the most serious complications of traversing the HLA barrier. According to clinical observations, killer immunoglobulin-like receptor (KIR) mismatch and donor-specific anti-HLA (DSA) antibodies-negative status play potential roles in reducing the risk of GVHD and graft failure following HLA-haploidentical SCT. New strategies to improve transplant outcomes include donor lymphocyte, NK cell and selected T-cell subset infusion, mesenchymal stem cell (MSC) co-transplantation and interleukin-2 (IL-2) application. Future challenges remain in improving post-transplant immune reconstitution and finding the best approach to reduce the incidence and severity of GVHD while simultaneously preserving the graft-versus leukemia effect to prevent the recurrence of underlying malignancy.