Stem cell transplantation for primary immunodeficiencies: the European experience

Epstein-Barr virus-associated smooth muscle tumors in immunocompromised patients: Six case reports

BACKGROUND

Epstein-Barr virus associated smooth muscle tumor (EBV-SMT) is a rare oncological entity. However, there is an increasing incidence of EBV-SMTs, as the frequency of organ transplantation and immunosuppression grows. EBV-SMT diagnosis relies on histopathology and immunochemical staining to distinguish it from post-transplant lymphoproliferative disorder (PTLD). There is no clear consensus on the treatment of EBV-SMTs. However, surgical resection, chemotherapy, radiation therapy, and immunosuppression reduction have been explored with varying degrees of success.

CASE SUMMARY

Our case series includes six cases of EBV-SMTs across different age groups, with different treatment modalities, adding to the limited existing literature on this rare tumor. The median latency time between immunosuppression and disease diagnosis is four years. EBV-SMTs present with variable degrees of aggressiveness and seem to have worse clinical outcomes in patients with tumor multiplicity and worse immunocompetency.

CONCLUSION

It is imperative to continue building on this knowledge and keeping EBV-SMTs on the differential in immunocompromised individuals.

Stem-cell transplantation for children with primary immune deficiencies: A retrospective study of 19 patients from one center in Mexico

INTRODUCTION

For many patients with Primary immune deficiency (PID), stem-cell transplantation (SCT) may be lifesaving.

OBJECTIVE

To review our experience of 11 years transplanting children with PID in Mexico.

METHODS

Chart review of patients who underwent SCT from 2008 to 2018, to describe their diagnoses, time to transplant, conditioning regime, survival rate and outcomes. All patients received post-transplant cyclophosphamide as graft-versus-host-disease (GVHD) prophylaxis.

RESULTS

19 patients with combined, phagocytic or syndromic PID from 5 states. Twelve of them were male (58%) and 14 survive (79%). Mean age at HSCT was 41.9 months; mean time from diagnosis, 31.2 months. Seven grafts were umbilical cord and 12 haploidentical. The conditioning regime was myeloablative, with seven primary graft failures. Two patients had partial and 10 full chimerism. Five patients died within 2 months after transplant. Immune reconstitution was complete in 11 of 19 patients. We found a prevalence of 21% GVHD.

DISCUSSION

We describe 19 patients from Mexico with 8 PID diagnoses who underwent allogenic HSCT over a period of 11 years. Survival rate and other outcomes compare well with industrialized countries. We recommend the use of post-transplant cyclophosphamide to prevent GVHD in scenarios of resource scarcity and a lack of HLA-identical donors.

Primary immunodeficiencies: HSCT experiences of a single center in Turkey

BACKGROUND

Primary immunodeficiency diseases (PID) are characterized by the occurrence of frequent infections and are caused by many genetic defects. Hematopoietic stem cell transplantation (HSCT) is the only curative treatment option for the majority of PID. As a Pediatric Hematology-Oncology-Immunology Transplantation Unit, we wanted to present our HSCT experience regarding treatment of primary immunodeficiency diseases.

METHODS

58 patients were included in the study between January 2014 and June 2019. We searched 9/10 or 10/10 matched-related donor (MRD) firstly, in the absence of fully matched-related donor. We screened matched unrelated donor (MUD) from donor banks. MRD was used in 24 (41.3%) patients, MUD in 20 (34.4%) patients, and haploidentical donors in 14 (24.1%) patients. Demographic data, HSCT characteristics, and outcome were evaluated. While 16 patients had severe combined immunodeficiency (SCID), the remaining was non-SCID.

RESULTS

Of the 58 patients, 38 were male and 20 were female. Median age at transplantation was 12 months (range: 2.5-172 months). Combined immunodeficiencies consisted 67.2% of patients. Mean follow-up time was 27 months (6 months-5 years). Median neutrophil, lymphocyte, and thrombocyte engraftment days were similar in comparison of both donor type and stem cell source. The most common complication was acute GvHD in 15 (25.8%) patients. In total, five patients (31%) belonging to the SCID group and 10 patients (23.8%) belonging to the non-SCID group died. Our total mortality rate was 15 (25.8%) in all patients.

CONCLUSIONS

We would like to present our HSCT experiences as a pediatric immunology transplantation center. Existing severe infections before transplantation period, BCGitis, and CMV are important issues of transplantation in Turkey. However, the follow-up time is shorter than some studies, our results regarding complications and survival are similar to previous reports.

Multicenter Outcome of Hematopoietic Stem Cell Transplantation for Primary Immune Deficiency Disorders in India

Background

Hematopoietic stem cell transplantation (HSCT) is the curative option for many primary immune deficiency disorders (PID). In the last 5 years, increased awareness, availability of diagnostics based on flow cytometry, genetic testing, improved supportive care, use of reduced toxicity conditioning, and success of haploidentical donor HSCT have improved access to HSCT for children with PID in India. We present results on children with PID who underwent HSCT across India and the factors that influenced outcome.

Patients and Methods

We collected retrospective data on the outcome of HSCT for PID from seven centers. We analyzed the impact of the type of PID, conditioning regimen, time period of HSCT- before or after January 2016, graft versus host disease prophylaxis, cause of mortality and overall survival.

Results

A total of 228 children underwent HSCT for PID at a median age of 12 months (range, 1 to 220 months) with a median follow up of 14.4 months. Infants accounted for 51.3% of the cohort and the male female ratio was 3:1. SCID (25%) and HLH (25%) were the more frequent diagnoses. Matched family donor was available in 36.4% and 44.3% children had a haploidentical HSCT. Reduced and myeloablative conditioning regimens were used with 64% children receiving a treosulfan based conditioning regimen. Peripheral blood stem cells were the predominant graft source at 69.3%. The survival in infants (60.2%) was inferior to children aged over 1 year (75.7% p value = 0.01). Children with Wiskott Aldrich syndrome (74.3%) and chronic granulomatous disease (82.6%) had the best outcomes. The survival was superior in children receiving HSCT from a matched sibling (78%) versus an alternate donor HSCT (61% p value = 0.04). In the cohort transplanted after January 2016 survival improved from 26.8% to 77.5% (p value = 0.00). Infection remains the main cause of mortality at in over 50% children. The 5-year overall survival rate was 68%.

Conclusion

Survival of children with PID undergoing HSCT in India has improved dramatically in last 5 years. Alternate donor HSCT is now feasible and has made a therapeutic option accessible to all children with PID.

Dissection of Signaling Events Downstream of the c-Mpl Receptor in Murine Hematopoietic Stem Cells Via Motif-Engineered Chimeric Receptors

Hematopoietic stem cells (HSCs) are a valuable resource in transplantation medicine. Cytokines are often used to culture HSCs aiming at better clinical outcomes through enhancement of HSC reconstitution capability. Roles for each signal molecule downstream of receptors in HSCs, however, remain puzzling due to complexity of the cytokine-signaling network. Engineered receptors that are non-responsive to endogenous cytokines represent an attractive tool for dissection of signaling events. We here tested a previously developed chimeric receptor (CR) system in primary murine HSCs, target cells that are indispensable for analysis of stem cell activity. Each CR contains tyrosine motifs that enable selective activation of signal molecules located downstream of the c-Mpl receptor upon stimulation by an artificial ligand. Signaling through a control CR with a wild-type c-Mpl cytoplasmic tail sufficed to enhance HSC proliferation and colony formation in cooperation with stem cell factor (SCF). Among a series of CRs, only one compatible with selective Stat5 activation showed similar positive effects. The HSCs maintained ex vivo in these environments retained long-term reconstitution ability following transplantation. This ability was also demonstrated in secondary recipients, indicating effective transmission of stem cell-supportive signals into HSCs via these artificial CRs during culture. Selective activation of Stat5 through CR ex vivo favored preservation of lymphoid potential in long-term reconstituting HSCs, but not of myeloid potential, exemplifying possible dissection of signals downstream of c-Mpl. These CR systems therefore offer a useful tool to scrutinize complex signaling pathways in HSCs.

Epstein-Barr Virus+ Smooth Muscle Tumors as Manifestation of Primary Immunodeficiency Disorders

Epstein–Barr virus positive (EBV⁺) smooth muscle tumors (SMTs) constitute a very rare oncological entity. They usually develop in the context of secondary immunodeficiency caused by human immunodeficiency virus infection or immunosuppressive treatment after solid organ transplantation. However, in a small fraction of predominantly pediatric patients, EBV⁺ SMTs may occur in patients with primary immunodeficiency disorders (PIDs), such as GATA2 and CARMIL2 deficiency. In secondary immunodeficiencies and when the underlying condition can not be cured, the treatment of EBV⁺ SMTs is based on surgery in combination with antiretroviral and reduced or altered immunosuppressive pharmacotherapy, respectively. Importantly, without definitive reconstitution of cellular immunity, long-term survival is poor. This is particularly relevant for patients with EBV⁺ SMTs on the basis of PIDs. Recently, allogeneic hematopoietic stem cell transplantation resulted in cure of immunodeficiency and EBV⁺ SMTs in a GATA2-deficient patient. We propose that in the absence of secondary immunodeficiency disorders patients presenting with EBV⁺ SMTs should be thoroughly evaluated for PIDs. Allogeneic hematopoietic stem cell transplantation should be taken into consideration, ideally in the setting of a prospective clinical trial.

Hematopoietic Stem Cell Transplant for Primary Immunodeficiency Diseases: A Single-Center Experience

OBJECTIVES

The only curative treatment for many patients with primary immunodeficiency disease is hematopoietic stem cell transplant. In this study, we report the transplant outcomes of patients with primary immunodeficiency diseases.

MATERIALS AND METHODS

Herein, we present the transplant outcomes of 20 patients with primary immunodeficiency disease seen at our center in Kayseri, Turkey, from 2010 to 2015.

RESULTS

The disease distribution of the 20 patients were as follows: 6 patients with severe combined immunodeficiency, 4 patients with hemophagocytic lymphohistiocytosis, 2 patients with chronic granulomatous disease, 2 patients with type 2 Griscelli syndrome, 2 patients with B-cell deficiency plus bone marrow failure, 1 patient with severe congenital neutropenia, 1 patient with X-linked lymphoproliferative disease, 1 patient with T-cell deficiency plus relapsed non-Hodgkin lymphoma, and 1 patient with type 1 leukocyte adhesion deficiency. Of the 20 patients, 11 received related HLA-matched, 6 received haploidentical, 2 received unrelated HLA-matched, and 1 received HLA-mismatched transplant. The median age at transplant was 21 months, and median follow-up was 5 months. Overall survival rate was 65%. Mean engraftment times for neutrophils and platelets were 14.25 ± 3.08 and 24.7 ± 11.4 days. Graft-versus-host disease was observed in 30% of patients.

CONCLUSIONS

Patients with primary immunodeficiency disease treated at our center had acceptable transplant outcomes. This study supports the use of hematopoietic stem cell transplant in patients with primary immunodeficiency disease.

Functional screen identifies regulators of murine hematopoietic stem cell repopulation

Holmfeldt et al. perform a transplant-based screen to identify regulators of HSPC engraftment and report that Foxa3 is critical for optimal HSC function after transplant.

Understanding the molecular regulation of hematopoietic stem and progenitor cell (HSPC) engraftment is paramount to improving transplant outcomes. To discover novel regulators of HSPC repopulation, we transplanted >1,300 mice with shRNA-transduced HSPCs within 24 h of isolation and transduction to focus on detecting genes regulating repopulation. We identified 17 regulators of HSPC repopulation: Arhgef5, Armcx1, Cadps2, Crispld1, Emcn, Foxa3, Fstl1, Glis2, Gprasp2, Gpr56, Myct1, Nbea, P2ry14, Smarca2, Sox4, Stat4, and Zfp521. Knockdown of each of these genes yielded a loss of function, except in the cases of Armcx1 and Gprasp2, whose loss enhanced hematopoietic stem cell (HSC) repopulation. The discovery of multiple genes regulating vesicular trafficking, cell surface receptor turnover, and secretion of extracellular matrix components suggests active cross talk between HSCs and the niche and that HSCs may actively condition the niche to promote engraftment. We validated that Foxa3 is required for HSC repopulating activity, as Foxa3^−/− HSC fails to repopulate ablated hosts efficiently, implicating for the first time Foxa genes as regulators of HSPCs. We further show that Foxa3 likely regulates the HSC response to hematologic stress. Each gene discovered here offers a window into the novel processes that regulate stable HSPC engraftment into an ablated host.

Congenital defects in V(D)J recombination

INTRODUCTION OR BACKGROUND

The V(D)J recombination is a DNA rearrangement process that generates the diversity of T and B lymphocyte immune repertoire. It proceeds through the generation of a DNA double-strand break (DNA-DSB) by the Rag1/2 lymphoid-specific factors, which is repaired by the non-homologous end joining (NHEJ) DNA repair pathway. V(D)J recombination also constitutes a checkpoint in the lymphoid development.

SOURCES OF DATA

V(D)J recombination defect results in severe combined immune deficiency (SCID) with a lack of T and B lymphocytes.

AREAS OF AGREEMENT

The V(D)J recombination represents one of the few programmed molecular events leading to DNA-DSBs that strictly relies on NHEJ. Two NHEJ factors, Artemis and XLF/Cernunnos, were identified through the molecular studies of SCID patients. Mutations in PRKDC and DNA Ligase IV genes also result in SCID.

GROWING POINTS

Studies in mice have demonstrated that XLF/Cernunnos is dispensable for V(D)J recombination in lymphoid cells but not for the repair of genotoxic-induced DNA-DSBs, which raises the question of the implication of Rag1/2 factors in the DNA repair phase of V(D)J recombination.

AREAS TIMELY FOR DEVELOPING RESEARCH

New factors of NHEJ, such as PAXX, are being identified. Patients with NHEJ deficiency (XRCC4) without immune deficiency were recently reported. We, therefore, may not have yet the complete picture of DNA-DSB repair in the context of V(D)J recombination.