Epstein-Barr virus infections after allogeneic stem cell transplantation: a comparison between non-malignant and malignant hematological disorders

Risk factors for post-transplant Epstein-Barr virus events in pediatric recipients of hematopoietic stem cell transplants

BACKGROUND

Epstein-Barr virus (EBV) can cause severe disease following hematopoietic stem cell transplant (HSCT), including post-transplant lymphoproliferative disorder (PTLD). The objective was to analyze risk factors associated with post-transplant EBV outcomes among pediatric allogeneic HSCT recipients.

METHODS

We used data from 156 pediatric allogeneic HSCT recipients enrolled in the Canadian multicenter TREASuRE study. Cox and Prentice-Williams-Petersen models were used to analyze risk factors for post-transplant EBV events including occurrence and recurrence of EBV DNAemia, increase in EBV viral load (EBV-VL), and preemptive use of rituximab, an effective therapy against PTLD.

RESULTS

Females were at higher risk for increasing EBV-VL (adjusted hazard ratio (HR) = 2.83 [95% confidence intervals (CI): 1.33-6.03]) and rituximab use (HR = 3.08 [1.14-8.30]), but had the same EBV DNAemia occurrence (HR = 1.21 [0.74-1.99]) and recurrence risks (HR=1.05 [0.70-1.58]) compared to males. EBV DNAemia was associated with recipient pre-transplant EBV seropositivity (HR = 2.47 [1.17-5.21]) and with graft from an EBV-positive donor (HR = 3.53 [1.95-6.38]). Anti-thymocyte globulin (ATG) was strongly associated with all EBV outcomes, including the use of rituximab (HR = 5.33 [1.47-19.40]). Mycophenolate mofetil (MMF) significantly decreased the risk of all EBV events including the rituximab use (HR = 0.13 [0.03-0.63]).

CONCLUSION

This study in pediatric allogeneic HSCT patients reveals a reduced risk of all EBV outcomes with the use of MMF. Risk factors for EBV events such as EBV-VL occurrence and recurrence include EBV positivity in the donor and recipient, and use of ATG, whereas risk factors for the most severe forms of EBV outcome (EBV-VL and the use of rituximab) include female sex and ATG use.

Factors Associated with Post-Transplant Active Epstein-Barr Virus Infection and Lymphoproliferative Disease in Hematopoietic Stem Cell Transplant Recipients: A Systematic Review and Meta-Analysis

This systematic review was undertaken to identify risk factors associated with post-transplant Epstein-Barr virus (EBV) active infection and post-transplant lymphoproliferative disease (PTLD) in pediatric and adult recipients of hematopoietic stem cell transplants (HSCT). A literature search was conducted in PubMed and EMBASE to identify studies published until 30 June 2020. Descriptive information was extracted for each individual study, and data were compiled for individual risk factors, including, when possible, relative risks with 95% confidence intervals and/or p-values. Meta-analyses were planned when possible. The methodological quality and potential for bias of included studies were also evaluated. Of the 3362 titles retrieved, 77 were included (62 for EBV infection and 22 for PTLD). The overall quality of the studies was strong. Several risk factors were explored in these studies, but few statistically significant associations were identified. The use of anti-thymocyte globulin (ATG) was identified as the most important risk factor positively associated with post-transplant active EBV infection and with PTLD. The pooled relative risks obtained using the random-effect model were 5.26 (95% CI: 2.92-9.45) and 4.17 (95% CI: 2.61-6.68) for the association between ATG and post-transplant EBV infection and PTLD, respectively. Other risk factors for EBV and PTLD were found in the included studies, such as graft-versus-host disease, type of conditioning regimen or type of donor, but results are conflicting. In conclusion, the results of this systematic review indicate that ATG increases the risk of EBV infection and PTLD, but the link with all other factors is either nonexistent or much less convincing.

[Infections in immunocompromised patients (II). The transplanted patient]

Los receptores de los diferentes tipos de trasplante presentan un riesgo elevado de infección. En los trasplantados de precursores hematopoyéticos predominan las infecciones nosocomiales. Durante el periodo posprendimiento temprano (30-100 días tras la infusión del trasplante), la incidencia de infección es más elevada en pacientes con enfermedad de injerto contra huésped. En el pulmón pueden aparecer lesiones nodulares por infección fúngica invasora o bien un patón difuso habitualmente secundario a infección vírica o a neumonía por P. jirovecii. Después de los primeros 100 días persiste un moderado riesgo de infección por microorganismos convencionales y oportunistas, como la infección tardía por CMV. Los avances en las técnicas quirúrgicas y el empleo de calcineurínicos han reducido la mortalidad por infecciones en trasplantados de órgano sólido. Durante el primer mes, son frecuentes las infecciones nosocomiales; entre el primer y sexto mes son más frecuentes las infecciones oportunistas dependientes de la inmunidad celular y a partir de sexto mes el riesgo baja y predominan las infecciones comunitarias semejantes a las de los pacientes inmunocompetentes.

Improvement in poor graft function after allogeneic hematopoietic stem cell transplantation upon administration of mesenchymal stem cells from third-party donors: a pilot prospective study

Poor graft function (PGF) is a refractory complication that occurs after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the present study, we prospectively evaluated the efficacy and safety of mesenchymal stem cells (MSCs) expanded from the bone marrow of a third-party donor to patients with PGF after allo-HSCT. Twenty patients with PGF (7 with primary and 13 with secondary PGF) received MSCs (1 × 10(6)/kg) one to three times at 28-day intervals. Seventeen patients were responsive to MSCs, whereas three were not. Within the first 100 days after MSC treatment, 13 patients developed 20 episodes of infection. Moreover, five patients experienced cytomegalovirus-DNA viremia, and seven experienced Epstein-Barr virus (EBV)-DNA viremia within the first 100 days after MSC treatment; three of the latter developed EBV-associated posttransplant lymphoproliferative disorders (PTLD) within the follow-up period. Grade II acute graft-versus-host disease (GVHD) occurred in one patient, and local chronic GVHD occurred in two patients after receiving MSC treatment, including one acute GVHD and one chronic GVHD, respectively, after accepting donor lymphocyte infusions due to PTLD. After a follow-up period of an average of 508 days (range 166-904 days) posttransplantation, 11 patients died. No short-term toxic side effects were observed after MSC treatment. Two patients experienced leukemic relapse. With the exception of three patients with PTLD, no secondary tumors occurred. These results indicate that MSCs derived from the bone marrow of a third-party donor are beneficial in the treatment of both primary and secondary PGF that develops after allo-HSCT. However, additional studies will be needed to determine whether such treatment might increase the risk of EBV infection and reactivation or the development of EBV-associated PTLD.

EBV-induced post transplant lymphoproliferative disorders: a persisting challenge in allogeneic hematopoetic SCT

EBV-induced post transplantation lymphoproliferative disorder (EBV-PTLD) is a life-threatening complication after allogeneic hematopoietic cell transplantation. Profound T-cell depletion of the allograft represents a major risk factor for EBV-PTLD. With regard to the increasing use of alternative stem cell sources such as cord blood or purified haploidentical stem cell grafts both associated with impaired immune reconstitution, the frequent occurrence of EBV-PTLD demands particular vigilance on laboratory changes and early symptoms. Here we have summarized today's knowledge about EBV-PTLD in a comprehensive review explaining the underlying mechanisms of EBV-based transformation, EBV-PTLD development, clinical presentation, incidence, diagnosis, screening, therapy and prognosis. In this context, we emphasize on the necessity of regularly applied screening tools and pre-emptive treatment strategies including anti-CD20 Abs particularly in high-risk patients to avoid disease progression to malignant lymphoma. Although EBV-PTLD has always been associated with a high mortality rate, novel immunotherapeutic approaches such as the transfer of EBV-specific T cells nowadays offer improved chances of disease control even at late stages.