Distinct EBV and CMV reactivation patterns following antibody-based immunosuppressive regimens in patients with severe aplastic anemia

Treatment of newly diagnosed severe aplastic anemia in children: Evidence-based recommendations

Severe aplastic anemia (SAA) is a rare potentially fatal hematologic disorder. Although overall outcomes with treatment are excellent, there are variations in management approach, including differences in treatment between adult and pediatric patients. Certain aspects of treatment are under active investigation in clinical trials. Because of the rarity of the disease, some pediatric hematologists may have relatively limited experience with the complex management of SAA. The following recommendations reflect an up-to-date evidence-based approach to the treatment of children with newly diagnosed SAA.

Virus-reactive T cells expanded in aplastic anemia eliminate hematopoietic progenitor cells by molecular mimicry

ABSTRACT

Acquired aplastic anemia is a bone marrow failure syndrome characterized by hypocellular bone marrow and peripheral blood pancytopenia. Frequent clinical responses to calcineurin inhibition and antithymocyte globulin strongly suggest critical roles for hematopoietic stem/progenitor cell-reactive T-cell clones in disease pathophysiology; however, their exact contribution and antigen specificities remain unclear. We determined differentiation states and targets of dominant T-cell clones along with their potential to eliminate hematopoietic progenitor cells in the bone marrow of 15 patients with acquired aplastic anemia. Single-cell sequencing and immunophenotyping revealed oligoclonal expansion and effector differentiation of CD8+ T-cell compartments. We reexpressed 28 dominant T-cell receptors (TCRs) of 9 patients in reporter cell lines to determine reactivity with (1) in vitro-expanded CD34+ bone marrow, (2) CD34- bone marrow, or (3) peptide pools covering immunodominant epitopes of highly prevalent viruses. Besides 5 cytomegalovirus-reactive TCRs, we identified 3 TCRs that recognized antigen presented on hematopoietic progenitor cells. T cells transduced with these TCRs eliminated hematopoietic progenitor cells of the respective patients in vitro. One progenitor cell-reactive TCR (11A5) also recognized an epitope of the Epstein-Barr virus-derived latent membrane protein 1 (LMP1) presented on HLA-A∗02:01. We identified 2 LMP1-related mimotopes within the human proteome as activating targets of TCR 11A5, providing proof of concept that molecular mimicry of viral and self-epitopes can drive T cell-mediated elimination of hematopoietic progenitor cells in aplastic anemia.

Guidelines for the diagnosis and management of adult aplastic anaemia: A British Society for Haematology Guideline

Pancytopenia with hypocellular bone marrow is the hallmark of aplastic anaemia (AA) and the diagnosis is confirmed after careful evaluation, following exclusion of alternate diagnosis including hypoplastic myelodysplastic syndromes. Emerging use of molecular cyto-genomics is helpful in delineating immune mediated AA from inherited bone marrow failures (IBMF). Camitta criteria is used to assess disease severity, which along with age and availability of human leucocyte antigen compatible donor are determinants for therapeutic decisions. Supportive care with blood and platelet transfusion support, along with anti-microbial prophylaxis and prompt management of opportunistic infections remain key throughout the disease course. The standard first-line treatment for newly diagnosed acquired severe/very severe AA patients is horse anti-thymocyte globulin and ciclosporin-based immunosuppressive therapy (IST) with eltrombopag or allogeneic haemopoietic stem cell transplant (HSCT) from a matched sibling donor. Unrelated donor HSCT in adults should be considered after lack of response to IST, and up front for young adults with severe infections and a readily available matched unrelated donor. Management of IBMF, AA in pregnancy and in elderly require special attention. In view of the rarity of AA and complexity of management, appropriate discussion in multidisciplinary meetings and involvement of expert centres is strongly recommended to improve patient outcomes.

COVID-19 in patients with anemia and haematological malignancies: risk factors, clinical guidelines, and emerging therapeutic approaches

Extensive research in countries with high sociodemographic indices (SDIs) to date has shown that coronavirus disease 2019 (COVID-19) may be directly associated with more severe outcomes among patients living with haematological disorders and malignancies (HDMs). Because individuals with moderate to severe immunodeficiency are likely to undergo persistent infections, shed virus particles for prolonged periods, and lack an inflammatory or abortive phase, this represents an overall risk of morbidity and mortality from COVID-19. In cases suffering from HDMs, further investigation is needed to achieve a better understanding of triviruses and a group of related variants in patients with anemia and HDMs, as well as their treatment through vaccines, drugs, and other methods. Against this background, the present study aimed to delineate the relationship between HDMs and the novel COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Besides, effective treatment options for HDM cases were further explored to address this epidemic and its variants. Therefore, learning about how COVID-19 manifests in these patients, along with exploiting the most appropriate treatments, may lead to the development of treatment and care strategies by clinicians and researchers to help patients recover faster. Video Abstract.

Detection and management of HLA sensitization in candidates for adult heart transplantation

Heart transplantation (HT) remains the preferred therapy for patients with advanced heart failure. However, for sensitized HT candidates who have antibodies to human leukocyte antigens , finding a suitable donor can be challenging and can lead to adverse waitlist outcomes. In recent years, the number of sensitized patients awaiting HT has increased likely due to the use of durable and mechanical circulatory support as well as increasing number of candidates with underlying congenital heart disease. This State-of-the-Art review discusses the assessment of human leukocyte antigens antibodies, potential desensitization strategies including mechanisms of action and specific protocols, the approach to a potential donor including the use of complement-dependent cytotoxicity, flow cytometry, and virtual crossmatches, and peritransplant induction management.

The impact of Rituximab administered before transplantation in patients undergoing allogeneic hematopoietic stem cell transplantation: A real-world study

Rituximab is used to eliminate B cells as a chimeric monoclonal antibody directed against CD20, a B-cell antigen expressed on B cells. To explore the impact of rituximab administered before transplantation, we implemented a retrospective, monocentric study and utilized real-world data collected at our center between January 2018 and December 2020, and then followed until December 2021. Based on whether a dose of 375mg/m2 rituximab was used at least once within two weeks before transplantation, patients undergoing allo-HSCT were classified into two groups: rituximab (N=176) and non-rituximab (N=344) group. Amongst all the patients, the application of rituximab decreased EBV reactivation (P<0.01) and rituximab was an independent factor in the prevention of EBV reactivation by both univariate and multivariate analyses (HR 0.56, 95%CI 0.33-0.97, P=0.04). In AML patients, there were significant differences in the cumulative incidence of aGVHD between the two groups (P=0.04). Our data showed that rituximab was association with a decreased incidence of aGVHD in AML patients according to both univariate and multivariate analyses. There was no difference between the two groups in other sets of populations. Thus, our study indicated that rituximab administered before transplantation may help prevent EBV reactivation in all allo-HSCT patients, as well as prevent aGVHD in AML patients after allo-HSCT.

[The diagnostic value of whole blood Epstein-Barr virus DNA load in lymphoproliferative diseases after allogeneic hematopoietic stem cell transplantation]

Objectives: To investigate the diagnostic value of whole blood quantitative PCR for DNA load of Epstein-Barr virus (EBV) in post-transplant lymphoproliferative disease (PTLD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: A total of 694 patients with hematologic diseases who underwent allo-HSCT at the Hematology Department of Peking University First Hospital from April 2004 to April 2019 were included, and their data were retrospectively analyzed. Results: ①Among the 694 cases, 29 cases (22 males and 7 females, with a median age of 22 (1-52) years) developed PTLD after allo-HSCT with a cumulative incidence of 4.2% and a median onset time of 2.1 (0.8-20.6) months. ② Univariate analysis showed that age<30 years, diagnosis with aplastic anemia, human leukocyte antigen (HLA) mismatch, use of antithymocyte globulin (ATG) in preconditioning regimens, and EBV reactivation were the risk factors for the occurrence of PTLD. Multivariate analysis showed that EBV reactivation was an independent risk factor for the occurrence of PTLD. ③Further analysis of EBV reactivation cases showed that the peak value of EBV-DNA load was significantly higher in the PTLD group than that in the non-PTLD group (P<0.001) and the incidence of PTLD increased with the increase of EBV-DNA load. Receiver operating characteristic (ROC) curve analysis indicated that PTLD was more likely to be diagnosed when the EBV-DNA load was >1.19×10(6) copies/ml (sensitivity 0.800 and specificity 0.768) . ④All patients with PTLD received rituximab-based treatment, with an overall response rate of 86.2% and an overall survival rate of 54.3%. Conclusion: The PTLD occurrence after allo-HSCT is highly correlated with EBV reactivation, and the higher the EBV-DNA load, the greater the risk of PTLD occurrence. The dynamic monitoring of EBV-DNA load plays an important role in predicting PTLD occurrence.

Validation of a Post-Transplant Lymphoproliferative Disorder Risk Prediction Score and Derivation of a New Prediction Score Using a National Bone Marrow Transplant Registry Database

BACKGROUND

We externally validated Fujimoto's post-transplant lymphoproliferative disorder (PTLD) scoring system for risk prediction by using the Taiwan Blood and Marrow Transplant Registry Database (TBMTRD) and aimed to create a superior scoring system using machine learning methods.

MATERIALS AND METHODS

Consecutive allogeneic hematopoietic cell transplant (HCT) recipients registered in the TBMTRD from 2009 to 2018 were included in this study. The Fujimoto PTLD score was calculated for each patient. The machine learning algorithm, least absolute shrinkage and selection operator (LASSO), was used to construct a new score system, which was validated using the fivefold cross-validation method.

RESULTS

We identified 2,148 allogeneic HCT recipients, of which 57 (2.65%) developed PTLD in the TBMTRD. In this population, the probabilities for PTLD development by Fujimoto score at 5 years for patients in the low-, intermediate-, high-, and very-high-risk groups were 1.15%, 3.06%, 4.09%, and 8.97%, respectively. The score model had acceptable discrimination with a C-statistic of 0.65 and a near-perfect moderate calibration curve (HL test p = .81). Using LASSO regression analysis, a four-risk group model was constructed, and the new model showed better discrimination in the validation cohort when compared with The Fujimoto PTLD score (C-statistic: 0.75 vs. 0.65).

CONCLUSION

Our study demonstrated a more comprehensive model when compared with Fujimoto's PTLD scoring system, which included additional predictors identified through machine learning that may have enhanced discrimination. The widespread use of this promising tool for risk stratification of patients receiving HCT allows identification of high-risk patients that may benefit from preemptive treatment for PTLD.

IMPLICATIONS FOR PRACTICE

This study validated the Fujimoto score for the prediction of post-transplant lymphoproliferative disorder (PTLD) development following hematopoietic cell transplant (HCT) in an external, independent, and nationally representative population. This study also developed a more comprehensive model with enhanced discrimination for better risk stratification of patients receiving HCT, potentially changing clinical managements in certain risk groups. Previously unreported risk factors associated with the development of PTLD after HCT were identified using the machine learning algorithm, least absolute shrinkage and selection operator, including pre-HCT medical history of mechanical ventilation and the chemotherapy agents used in conditioning regimen.

Relationship between plasma rabbit anti-thymocyte globulin concentration and immunosuppressive therapy response in patients with severe aplastic anemia

OBJECTIVES

Patients with acquired aplastic anemia (AA) without HLA-matched sibling donors or aged >40 years receive immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG). We investigated the relationship between plasma rabbit ATG (r-ATG) concentration and IST response.

METHODS

From May 2012 to October 2017, 81 patients with severe AA who required initial IST were included. A 1:1 block randomization was employed for 2.5 and 3.5 mg/kg doses of r-ATG.

RESULTS

No significant difference in response rates was observed between the 2.5 and 3.5 mg/kg groups (63% vs. 58%, P = .894). Median r-ATG concentrations on days 14 and 28 after IST were 15.2 (0.0-97.7) and 1.8 (0.0-74.9 µg/mL), respectively. According to r-ATG concentration, response rates were significantly higher in the group with higher r-ATG concentration than in those with lower r-ATG concentration (day 14, 88% vs. 52%; P = .006 and day 28, 79% vs. 46%; P = .005). In multivariate analysis, higher r-ATG concentrations at day 28 were independent predictors of favorable response to IST at 6 months (odds ratio, 0.29; 95% confidence interval, 0.09-0.93; P = .037).

CONCLUSIONS

The present data indicate that higher r-ATG concentration at day 28 resulted in improved IST response.

Age and CMV-Infection Jointly Affect the EBV-Specific CD8+ T-Cell Repertoire

CD8⁺ T cells play an important role in protection against viral infections. With age, changes in the T-cell pool occur, leading to diminished responses against both new and recurring infections in older adults. This is thought to be due to a decrease in both T-cell numbers and T-cell receptor (TCR) diversity. Latent infection with cytomegalovirus (CMV) is assumed to contribute to this age-associated decline of the immune system. The observation that the level of TCR diversity in the total memory T-cell pool stays relatively stable during aging is remarkable in light of the constant input of new antigen-specific memory T cells. What happens with the diversity of the individual antigen-specific T-cell repertoires in the memory pool remains largely unknown. Here we studied the effect of aging on the phenotype and repertoire diversity of CMV-specific and Epstein-Barr virus (EBV)-specific CD8⁺ T cells, as well as the separate effects of aging and CMV-infection on the EBV-specific T-cell repertoire. Antigen-specific T cells against both persistent viruses showed an age-related increase in the expression of markers associated with a more differentiated phenotype, including KLRG-1, an increase in the fraction of terminally differentiated T cells, and a decrease in the diversity of the T-cell repertoire. Not only age, but also CMV infection was associated with a decreased diversity of the EBV-specific T-cell repertoire. This suggests that both CMV infection and age can impact the T-cell repertoire against other antigens.

Acquired severe aplastic anaemia: how medical therapy evolved in the 20th and 21st centuries

The progress in aplastic anaemia (AA) management is one of success. Once an obscure entity resulting in death in most affected can now be successfully treated with either haematopoietic stem cell transplantation (HSCT) or immunosuppressive therapy (IST). The mechanisms that underly the diminution of haematopoietic stem cells (HSCs) are now better elucidated, and include genetics and immunological alterations. Advances in supportive care with better antimicrobials, safer blood products and iron chelation have greatly impacted AA outcomes. Working somewhat 'mysteriously', anti-thymocyte globulin (ATG) forms the base for both HSCT and IST protocols. Efforts to augment immunosuppression potency have not, unfortunately, led to better outcomes. Stimulating HSCs, an often-sought approach, has not been effective historically. The thrombopoietin receptor agonists (Tpo-RA) have been effective in stimulating early HSCs in AA despite the high endogenous Tpo levels. Dosing, timing and best combinations with Tpo-RAs are being defined to improve HSCs expansion in AA with minimal added toxicity. The more comprehensive access and advances in HSCT and IST protocols are likely to benefit AA patients worldwide. The focus of this review will be on the medical treatment advances in AA.

CCR5 maintains macrophages in the bone marrow and drives hematopoietic failure in a mouse model of severe aplastic anemia

Severe aplastic anemia (SAA) is an acquired, T cell-driven bone marrow (BM) failure disease characterized by elevated interferon gamma (IFNγ), loss of hematopoietic stem cells (HSCs), and altered BM microenvironment, including dysfunctional macrophages (MΦs). T lymphocytes are therapeutic targets for treating SAA, however, the underlying mechanisms driving SAA development and how innate immune cells contribute to disease remain poorly understood. In a murine model of SAA, increased beta-chemokines correlated with disease and were partially dependent on IFNγ. IFNγ was required for increased expression of the chemokine receptor CCR5 on MΦs. CCR5 antagonism in murine SAA improved survival, correlating with increased platelets and significantly increased platelet-biased CD41^hi HSCs. T cells are key drivers of disease, however, T cell-specific CCR5 expression and T cell-derived CCL5 were not necessary for disease. CCR5 antagonism reduced BM MΦs and diminished their expression of Tnf and Ccl5, correlating with reduced frequencies of IFNγ-secreting BM T cells. Mechanistically, CCR5 was intrinsically required for maintaining BM MΦs during SAA. Ccr5 expression was significantly increased in MΦs from aged mice and humans, relative to young counterparts. Our data identify CCR5 signaling as a key axis promoting the development of IFNγ-dependent BM failure, particularly relevant in aging where Ccr5 expression is elevated.

Infectious Complications in Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia (AIHA) may be frequently challenged by infectious complications, mainly as a result of immunosuppressive treatments administered. Furthermore, infectious agents are known triggers of AIHA onset and relapse. Although being risk factors for mortality, infections are an underestimated issue in AIHA. This review will collect the available evidence on the frequency and type of infectious complications in AIHA, detailing the risk related to each treatment (i.e., steroids, rituximab, splenectomy, classic immunosuppressive agents, and new target drugs). Moreover, we will briefly discuss the infectious complications in AIHA secondary to other diseases that harbor an intrinsic infectious risk (e.g., primary immunodeficiencies, systemic autoimmune diseases, lymphoproliferative disorders, solid organ and hematopoietic stem cell transplants). Finally, viral and bacterial reactivations during immune suppressive therapies will be discussed, along with suggested screening and prophylactic strategies.

How age and infection history shape the antigen-specific CD8+ T-cell repertoire: Implications for vaccination strategies in older adults

Older adults often show signs of impaired CD8⁺ T‐cell immunity, reflected by weaker responses against new infections and vaccinations, and decreased protection against reinfection. This immune impairment is in part thought to be the consequence of a decrease in both T‐cell numbers and repertoire diversity. If this is indeed the case, a strategy to prevent infectious diseases in older adults could be the induction of protective memory responses through vaccination at a younger age. However, this requires that the induced immune responses are maintained until old age. It is therefore important to obtain insights into the long‐term maintenance of the antigen‐specific T‐cell repertoire. Here, we review the literature on the maintenance of antigen‐experienced CD8⁺ T‐cell repertoires against acute and chronic infections. We describe the complex interactions that play a role in shaping the memory T‐cell repertoire, and the effects of age, infection history, and T‐cell avidity. We discuss the implications of these findings for the development of new vaccination strategies to protect older adults.

Solar Ultraviolet Radiation and Vitamin D Deficiency on Epstein-Barr Virus Reactivation: Observational and Genetic Evidence From a Nasopharyngeal Carcinoma-Endemic Population

Background

We investigated the relationship of Epstein-Barr virus viral capsid antigen (EBV VCA-IgA) serostatus with ambient and personal ultraviolet radiation (UVR) and vitamin D exposure.

Methods

Using data from a multicenter case-control study, we included 1026 controls subjects in 2014–2017 in Hong Kong, China. Odds ratios (ORs) and 95% confidence intervals (CIs) of the association between UVR exposure and EBV VCA-IgA (seropositivity vs seronegativity) were calculated using unconditional logistic regression models adjusted for potential confounders.

Results

We observed a large increase in seropositivity of EBV VCA-IgA in association with duration of sunlight exposures at both 10 years before recruitment and age 19–30 years (adjusted OR = 3.59, 95% CI = 1.46–8.77; and adjusted OR = 2.44, 95% CI = 1.04–5.73 for ≥8 vs <2 hours/day; P for trend = .005 and .048, respectively). However, no association of EBV VCA-IgA serostatus with other indicators of UVR exposure was found. In addition, both circulating 25-hydroxyvitamin D (25OHD) and genetic predicted 25OHD were not associated with EBV VCA-IgA serostatus.

Conclusions

Our results suggest that personal UVR exposure may be associated with higher risk of EBV reactivation, but we did not find clear evidence of vitamin D exposure (observational or genetic), a molecular mediator of UVR exposure. Further prospective studies in other populations are needed to confirm this finding and to explore the underlying biological mechanisms. Information on photosensitizing agents, and serological markers of EBV, and biomarkers related to systemic immunity and inflammation should be collected and are also highly relevant in future studies.

Autologous haematopoietic stem cell transplantation and other cellular therapy in multiple sclerosis and immune-mediated neurological diseases: updated guidelines and recommendations from the EBMT Autoimmune Diseases Working Party (ADWP) and the Joint Accreditation Committee of EBMT and ISCT (JACIE)

These updated EBMT guidelines review the clinical evidence, registry activity and mechanisms of action of haematopoietic stem cell transplantation (HSCT) in multiple sclerosis (MS) and other immune-mediated neurological diseases and provide recommendations for patient selection, transplant technique, follow-up and future development. The major focus is on autologous HSCT (aHSCT), used in MS for over two decades and currently the fastest growing indication for this treatment in Europe, with increasing evidence to support its use in highly active relapsing remitting MS failing to respond to disease modifying therapies. aHSCT may have a potential role in the treatment of the progressive forms of MS with a significant inflammatory component and other immune-mediated neurological diseases, including chronic inflammatory demyelinating polyneuropathy, neuromyelitis optica, myasthenia gravis and stiff person syndrome. Allogeneic HSCT should only be considered where potential risks are justified. Compared with other immunomodulatory treatments, HSCT is associated with greater short-term risks and requires close interspeciality collaboration between transplant physicians and neurologists with a special interest in these neurological conditions before, during and after treatment in accredited HSCT centres. Other experimental cell therapies are developmental for these diseases and patients should only be treated on clinical trials.

Reactivation and dynamics of cytomegalovirus and Epstein-Barr virus after rabbit antithymocyte globulin and cyclosporine for aplastic anemia

OBJECTIVES

This study aimed to identify the natural course of cytomegalovirus (CMV)/Epstein-Barr virus (EBV) after rabbit antithymocyte globulin and cyclosporine (rATG-CsA) for aplastic anemia (AA).

METHODS

In 113 prospectively observed AA patients treated with rATG-CsA, the CMV/EBV cohort was classified into two groups by baseline viremic status: no viremia (CMV-G1, n = 112; EBV-G1, n = 98) and the presence of viremia (CMV-G2, n = 1; EBV-G2, n = 13).

RESULTS

In CMV-G1, the mean CMV load increased up to 3 months but was completely resolved from 6 months. The mean EBV load of EBV-G1 showed a peak at 1 month and then gradually decreased over time but remained detectable throughout the observation period. EBV-G2 showed fluctuating EBV dynamics. With reactivation rates of 38.4% in CMV-G1 and 62.2% in EBV-G1, a longer time to rATG-CsA from diagnosis and a lower absolute lymphocyte count at 1 month from rATG-CsA were significantly associated with CMV and EBV reactivation, respectively. The mean peak CMV and EBV loads of patients with CMV-related (3.5%) and EBV-related (0.9%) diseases were evidently higher than those of the remaining patients without CMV and EBV diseases in the respective cohort.

CONCLUSION

Considering frequent reactivation and distinct courses of CMV/EBV, virologic surveillance is recommended after rATG-CsA for AA.

Haploidentical transplantation using low-dose alemtuzumab: Comparison with haploidentical transplantation using low-dose thymoglobulin

OBJECTIVES

To establish the optimal strategy for haploidentical hematopoietic stem cell transplantation (HSCT).

METHODS

We performed a prospective study on haploidentical HSCT using low-dose alemtuzumab. Alemtuzumab was added at 0.25 mg/kg for 2 days. The primary outcome measure was the survival rate with the engraftment of donor cells and without grade III-IV acute graft-vs-host disease (GVHD) at 60 days after transplantation.

RESULTS

Fourteen adult patients with advanced hematological disease were enrolled. The primary outcome measure was achieved in 86% of the patients. Six patients experienced relapse/progression. Non-relapse death was observed in three patients, and all of them had a history of previous allogeneic HSCT. Overall survival and progression-free survival rates at 1 year were 51% and 43%, respectively. Four patients were suspected to have herpes simplex virus infection and three had aseptic meningitis under the use of acyclovir at 200 mg. There were no deaths due to viral infection. Compared to those who underwent haploidentical HSCT using thymoglobulin, patients with alemtuzumab showed a slower recovery of CD8⁺ T-cells and lower incidences of GVHD and EB virus reactivation.

CONCLUSIONS

Haploidentical HSCT using low-dose alemtuzumab can be performed safely. We need to overcome the high relapse/progression rate in non-remission patients.

Epstein-Barr virus post-transplant lymphoproliferative disease (PTLD) after hematopoietic stem cell transplantation

Epstein-Barr virus (EBV) viremia and post-transplant lymphoproliferative disease (PTLD) are severe complications after hematopoietic stem cell transplantation (HSCT). A series of risk factors have been found to predict EBV viremia and PTLD, including the T-cell depletion, reduced intensity conditioning, and alternative donor. The rituximab pre-emptive therapy could improve PTLD prognosis significantly, but the trigger of initiating rituximab pre-emptive therapy has not been well established. Additionally, EBV-specific cytotoxic T cell (CTL) is a promising approach to treat EBV-PTLD.

Rabbit antithymocyte globulin dose does not affect response or survival as first-line therapy for acquired aplastic anemia: a multicenter retrospective study

In a prospective randomized study, treatment for aplastic anemia (AA) with rabbit antithymocyte globulin (r-ATG) and cyclosporine showed inferior hematological response and survival in comparison to horse antithymocyte globulin (h-ATG) and cyclosporine. However, h-ATG was discontinued in most Asian, South American, and European countries, where r-ATG became the only ATG formulation available. We retrospectively evaluated consecutive patients with acquired AA who received either rabbit (n = 170) or horse (n = 85) ATG and cyclosporine for first-line treatment from 1992 to 2014 in seven referral centers in Brazil and Argentina. Overall response at 3 months was 17% (95%CI, 11-23%) for r-ATG and 44% (95%CI, 33-55%) for h-ATG (p < 0.001). At 6 months, it was 31% (95%CI, 34-39%) for r-ATG and 59% (95%CI, 48-69%) for h-ATG (p < 0.001). Overall survival at 5 years was 57% (95%CI, 47-65%) for r-ATG and 80% (95%CI, 69-87%) for h-ATG (log-rank = 0.001). Relapse was significantly higher in patients receiving h-ATG (28%; 95%CI, 17-43%) as compared to r-ATG (9.4%; 95%CI, 4-21%; log-rank, p = 0.01). The type of ATG was the only factor associated with both response and survival. The r-ATG dose varied from 1 to 5 mg/kg/day, but it did not correlate with outcomes. In summary, this is the largest multicenter study comparing the two ATG formulations in AA. Our results indicate that the dose of r-ATG does not influence hematologic response or survival in first-line therapy for acquired AA. Considering the toxicity and costs of r-ATG, our findings challenge its aggregate benefit to cyclosporine therapy and further strengthen that h-ATG should remain standard therapy in AA.

The Pathophysiology of Acquired Aplastic Anemia: Current Concepts Revisited

Idiopathic acquired aplastic anemia is a rare, life-threatening bone marrow failure syndrome characterized by cytopenias and hypocellular bone marrow. The pathophysiology is unknown; the most favored model is of a dysregulated immune system leading to autoreactive T-cell destruction of hematopoietic stem and progenitor cells in a genetically susceptible host. The authors review the literature and propose that the major driver of acquired aplastic anemia is a combination of hematopoietic stem and progenitor cells intrinsic defects and an inappropriately activated immune response in the setting of a viral infection. Alterations in bone marrow microenvironment may also contribute to the disease process.

Graves' disease following allogenic hematopoietic stem cell transplantation for severe aplastic anemia: case report and literature review

BACKGROUND

Similar autoimmune processes (defective T-cell function) take place during the pathogenesis of aplastic anemia (AA) and Graves' disease (GD). Antithyroid drugs used for the management of GD may induce AA and GD may occur following treatment of severe aplastic anemia (SAA).

CASE PRESENTATION

Clinical and laboratory investigations were performed for an 11-year-and-2-month-old girl who was referred for bilateral exophthalmus and abnormal thyroid function tests. She had been diagnosed as having severe acquired AA at the age of 8 years and had been treated with allogenic hematopoietic stem cell transplantation from her healthy human leukocyte antigen-matched sibling donor. Clinical examination revealed a weight of 32.6 kg (-0.88 standard deviation [SD] score); height, 145.7 cm (-0.14 SD score); body mass index 15.5 kg/m2 (-1.01 SD score); heart rate, 110/min; blood pressure, 128/74 mmHg; bilateral exophthalmos and an enlarged thyroid gland. The laboratory workup showed hemoglobin of 11.1 g/dL; white blood cells, 7500/mL; platelets, 172,000/mL; free thyroxine (FT4), 4.80 ng/dL (normal, 0.5-1.51); free triiodothyronine (FT3), 17.7 pg/mL (normal, 2.5-3.9); thyrotropin (TSH), 0.015 mIU/mL (normal, 0.38-5.3); antithyroglobulin peroxidase (TPO) antibody, 61.7 IU/mL (normal, 0-9); antithyroglobulin (TG) antibody, <0.9 IU/mL (normal, 0-4) and thyrotropin (TSH) receptor antibodies 14 U/L (normal, 0-1). Doppler ultrasonography showed diffuse enlargement of the thyroid gland and increased vascularity. She was treated with methimazole (0.6 mg/kg/day). L-thyroxine treatment was also needed (50 μg/day). Thrombocytopenia developed during follow-up. A thyroidectomy was performed for definitive treatment at the 14th month of treatment.

CONCLUSIONS

The association of hyperthyroidism and AA in the pediatric age group is rare. The long-term use of antithyroid drugs and radioactive iodine should be avoided due to their hematologic toxic side effects.

Cyclophilin A as a target in the treatment of cytomegalovirus infections

BACKGROUND

Viruses are obligate parasites that depend on the cellular machinery of the host to regenerate and manufacture their proteins. Most antiviral drugs on the market today target viral proteins. However, the more recent strategies involve targeting the host cell proteins or pathways that mediate viral replication. This new approach would be effective for most viruses while minimizing drug resistance and toxicity.

METHODS

Cytomegalovirus replication, latency, and immune response are mediated by the intermediate early protein 2, the main protein that determines the effectiveness of drugs in cytomegalovirus inhibition. This review explains how intermediate early protein 2 can modify the action of cyclosporin A, an immunosuppressive, and antiviral drug. It also links all the pathways mediated by cyclosporin A, cytomegalovirus replication, and its encoded proteins.

RESULTS

Intermediate early protein 2 can influence the cellular cyclophilin A pathway, affecting cyclosporin A as a mediator of viral replication or anti-cytomegalovirus drug.

CONCLUSION

Cyclosporin A has a dual function in cytomegalovirus pathogenesis. It has the immunosuppressive effect that establishes virus replication through the inhibition of T-cell function. It also has an anti-cytomegalovirus effect mediated by intermediate early protein 2. Both of these functions involve cyclophilin A pathway.

Hepatitis B in renal transplant patients

Hepatitis B virus (HBV) poses a significant challenge for both dialysis patients and kidney transplant recipients despite its decreasing rates, especially in developed countries. The best preventive method is vaccination. Patients with chronic renal disease should ideally be vaccinated prior to dialysis, otherwise, reinforced vaccination practices and close antibody titer monitoring should be applied while on dialysis. HBV infected dialysis patients who are renal transplant candidates must be thoroughly examined by HBV-DNA, and liver enzyme testing and by liver biopsy. When needed, one must consider treating patients with tenofovir or entecavir rather than lamivudine. Depending on the cirrhosis stage, dialysis patients are eligible transplant recipients for either a combined kidney-liver procedure in the case of decompensated cirrhosis or a lone kidney transplantation since even compensated cirrhosis after sustained viral responders is no longer considered an absolute contraindication. Nucleoside analogues have led to improved transplantation outcomes with both long-term patient and graft survival rates nearing those of HBsAg(-) recipients. Moreover, in the cases of immunized HBsAg(-) potential recipients with concurrent prophylaxis, we are enabled today to safely use renal grafts from both HBsAg(+) and HBsAg(-)/anti-HBc(+) donors. In so doing, we avoid unnecessary organ discarding. Universal prophylaxis with entecavir is recommended in HBV kidney recipients and should start perioperatively. One of the most important issues in HBV(+) kidney transplantation is the duration of antiviral prophylaxis. In the absence of robust data, it seems that prophylactic treatment may be discontinued in selected stable, low-risk recipients during maintenance immunosuppression and should be reintroduced when the immune status is altered. All immunosuppressive agents in kidney transplantation can be used in HBV(+) recipients. Immunosuppression is intimately associated with increased viral replication; thus it is important to minimize the total immunosuppression burden long term.

Prevalence and clinical outcomes of hepatitis B virus infection in patients with aplastic anemia

The association of HBV infection with other hematopoietic diseases has been discussed previously. However, the clinical significance and clinical outcomes of HBV infection in AA patients have not been clarified. In this study, we sought to investigate the prevalence and related events of HBV in patients with AA who received immunosuppressive therapy. We retrospectively analyzed 245 patients with acquired AA. The HBsAg positivity rate was 14.69% in this group of AA patients. No significant difference was observed in the severity of AA patients with HBV infection and in those without (P = 0.6358). HBV reactivation occurred in 4.76% of HBsAg-positive patients who received ATG/ALG + CsA treatment without anti-viral prophylaxis. HBV-infected patients who received CsA alone did not develop reactivation. Patients with HBV reactivation showed favorable clinical outcomes, with no HBV-related deaths. There was no significant difference in overall probability of survival in patients with different HBV infection status (P = 0.8617). Given the low rate of reactivation and favorable outcomes after reactivation in AA patients, close monitoring of HBV DNA, hepatic function and patient immune status may be a more effective approach than routine prophylaxis for AA patients with HBV infection undergoing ATG/ALG + CsA treatment. Further studies are warranted to clarify the optimal time to initiate anti-viral treatment.

ATG in allogeneic stem cell transplantation: standard of care in 2017? Counterpoint

Publisher's Note: This article has a companion Point by Bacigalupo. Publisher's Note: Join in the discussion of these articles at Blood Advances Community Conversations.

Effect of antithymocyte globulin source on outcomes of bone marrow transplantation for severe aplastic anemia

For treatment of severe aplastic anemia, immunosuppressive therapy with horse antithymocyte globulin results in superior response and survival compared with rabbit antithymocyte globulin. This relative benefit may be different in the setting of transplantation as rabbit antithymocyte globulin results in more profound immunosuppression. We analyzed 833 severe aplastic anemia transplants between 2008 and 2013 using human leukocyte antigen (HLA)-matched siblings (n=546) or unrelated donors (n=287) who received antithymocyte globulin as part of their conditioning regimen and bone marrow graft. There were no differences in hematopoietic recovery by type of antithymocyte globulin. Among recipients of HLA-matched sibling transplants, day 100 incidence of acute (17% versus 6%, P<0.001) and chronic (20% versus 9%, P<0.001) graft-versus-host disease were higher with horse compared to rabbit antithymocyte globulin. There were no differences in 3-year overall survival, 87% and 92%, P=0.76, respectively. Among recipients of unrelated donor transplants, acute graft-versus-host disease was also higher with horse compared to rabbit antithymocyte globulin (42% versus 23%, P<0.001) but not chronic graft-versus-host disease (38% versus 32%, P=0.35). Survival was lower with horse antithymocyte globulin after unrelated donor transplantation, 75% versus 83%, P=0.02. These data support the use of rabbit antithymocyte globulin for bone marrow transplant conditioning for severe aplastic anemia.

Epstein-Barr Virus-associated Lymphoproliferative Disorder with Encephalitis Following Anti-thymocyte Globulin for Aplastic Anemia Resolved with Rituximab Therapy: A Case Report and Literature Review

Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPDs) sometimes occur following Anti-thymocyte globulin (ATG) administration for allogenic stem cell transplantation but are rare in aplastic anemia (AA) patients. A 55-year-old woman with AA following ATG developed refractory fever and was diagnosed with EBV-LPD. She was successfully treated with weekly rituximab monotherapy; however, she developed EBV encephalitis. She was admitted to the intensive care unit and finally recovered from unconsciousness. EBV-LPD should be considered after ATG for AA when symptoms appear. Because EBV-LPD following ATG for AA can rapidly progress, weekly monitoring of EBV-DNA and early intervention may be necessary.

Successful Treatment of Epstein-Barr Virus-Associated Lymphoproliferative Disorder with Rituximab in a Patient Undergoing Immunosuppressive Therapy for Aplastic Anemia

Epstein-Barr virus-associated lymphoproliferative disorder (EBV-LPD) is a currently emerging serious complication in immunosuppressed patients, especially in allogeneic transplant recipients. Several fatal cases of EBV-LPD have been reported in aplastic anemia (AA) patients receiving immunosuppressive therapy (IST) with antithymocyte globulin (ATG) plus cyclosporine A (CsA), but no appropriate prophylactic or therapeutic strategy has been established. Herein, we describe a 29-year-old man whose EBV-LPD was successfully treated with rituximab. He received IST with ATG plus CsA for hepatitis-associated AA. EBV-DNA in plasma, which was not detectable before IST, gradually increased after IST initiation. A high fever and systemic lymphadenopathy developed 31 days after IST initiation. An EBV-DNA titer of 5.7 × 105 copies/μl was detected, and a diagnosis of EBV-LPD was made. Although discontinuation of IST was not effective, a single dose of rituximab on day 33 resolved the clinical symptoms and completely eliminated EBV-DNA. Even after restarting CsA administration, no elevation of EBV-DNA was observed, and his complete blood cell count had fully recovered 1 year after IST. This case suggests that this treatment strategy for EBV-LPD with EBV-DNA monitoring and rituximab administration, which has been recommended in allogeneic transplant recipients, may also be useful in the context of AA patients receiving IST.

Current management of severe acquired aplastic anemia

Overall survival in severe aplastic anemia has markedly improved in the past four decades due to advances in stem cell transplantation, immunosuppressive therapies and supportive care. Horse anti-thymocyte globulin plus cyclosporine is the standard immunosuppressive regimen in severe aplastic anemia, and often employed as initial therapy as most are not candidates for a matched related stem cell transplantation. With this regimen, hematologic response can be achieved in 60 to 70% of cases, but relapse is observed in 30 to 40% of responders and clonal evolution in 10 to 15% of patients. Efforts to improve outcomes beyond horse anti-thymocyte globulin plus cyclosporine have been disappointing, with no significant improvement in the critical parameter of hematologic response, which strongly correlates with long-term survival in severe aplastic anemia. Furthermore, rates of relapse and clonal evolution have also not improved with the development of three drug regimens or with more lymphocytotoxic therapies. Therefore, horse anti-thymocyte globulin plus cyclosporine remains the standard immunosuppression of choice as first therapy in severe aplastic anemia. Interestingly, survival has markedly improved over the years in large part due to better anti-infective therapy and more successful salvage therapies with immunosuppression and stem cell transplantation. In this review general aspects of diagnosis and management are discussed.

Alemtuzumab in T-cell large granular lymphocytic leukaemia: interim results from a single-arm, open-label, phase 2 study

Background

T-cell large granular lymphocytic leukemia (T-LGL) is a lymphoproliferative disease presenting with immune-mediated cytopenias and characterized by clonal expansion of cytotoxic CD3⁺CD8⁺ lymphocytes. Methotrexate, cyclosporine, or cyclophosphamide improve cytopenias in 50% of patients as first therapy, but the activity of an anti-CD52 monoclonal antibody, alemtuzumab, is not defined in T-LGL.

Methods

Twenty-five consecutive subjects with T-LGL were enrolled from October 2006 to March 2015 at the National Institutes of Health (www.clinicaltrials.gov-NCT00345345). Alemtuzumab was administered at 10 mg/day intravenously for 10 days. The primary endpoint was haematologic response at 3 months. Analysis was intention to treat. Here we report the protocol specified interim benchmark of a phase II clinical trial using alemtuzumab in T-LGL.

Findings

In this heterogeneous, previously treated cohort, 14/25 (56%; 95% CI, 37–73%) subjects had a haematological response at 3 months. In T-LGL cases not associated with myelodysplasia or marrow transplantation, the response rate was 14/19 (74%; 95% CI, 51–86%). First dose infusion reactions were common which improved with symptomatic therapy. EBV and CMV reactivations were common and subclinical. In only 2 patients pre-emptive anti-CMV therapy was instituted. There were no cases of EBV or CMV disease. Alemtuzumab induced sustained reduction of absolute clonal population of T-cytotoxic lymphocytes, as identified by TCRBV-receptor phenotype, but the abnormal clone serendipitously persisted in responders. STAT3 mutations in the SH2 domain, identified in ten subjects, did not correlate with response. When compared with healthy volunteers, T-LGL subjects showed a distinct plasma cytokine and JAK-STAT signature prior to treatment, but neither correlated to response.

Interpretation

This is the largest and only prospective cohort of T-LGL subjects treated with alemtuzumab yet reported. The high activity with a single course of a lymphocytotoxic agent in a mainly relapsed and refractory suggests that haematologic response outcomes can be accomplished without the need for continued use of oral immunosuppression.

Funding

This research was supported by the Intramural Research Program of the NIH, National Heart, Lung, and Blood Institute.

B-Cell-Rich T-Cell Lymphoma Associated with Epstein-Barr Virus-Reactivation and T-Cell Suppression Following Antithymocyte Globulin Therapy in a Patient with Severe Aplastic Anemia

B-cell lymphoproliferative disorder (B-LPD) is generally characterized by the proliferation of Epstein-Barr virus (EBV)-infected B lymphocytes. We here report the development of EBV-negative B-LPD associated with EBV-reactivation following antithymocyte globulin (ATG) therapy in a patient with aplastic anemia. The molecular autopsy study showed the sparse EBV-infected clonal T cells could be critically involved in the pathogenesis of EBV-negative oligoclonal B-LPD through cytokine amplification and escape from T-cell surveillances attributable to ATG-based immunosuppressive therapy, leading to an extremely rare B-cell-rich T-cell lymphoma. This report helps in elucidating the complex pathophysiology of intractable B-LPD refractory to rituximab.

Fatal Epstein-Barr Virus Reactivation in an Acquired Aplastic Anemia Patient Treated with Rabbit Antithymocyte Globulin and Cyclosporine A

Epstein-Barr virus (EBV) associated lymphoproliferative disorder (LPD) after immunosuppressive therapy for aplastic anemia (AA) is extremely rare in a nontransplant setting and has not been well described. This report describes a severe AA patient in whom fatal EBV-LPD developed after being treated with rabbit antithymocyte globulins (ATG) and cyclosporine A (CsA). An 81-year-old man was diagnosed as having severe AA. He was started on CsA followed by administration of ATG for five consecutive days. One month after the start of ATG, persistent fever which was not responsive to antibiotics or antifungal agents developed and atypical lymphocytes emerged in peripheral blood. Repeated blood cultures were negative. An extremely high level of EBV virus in his peripheral blood plasma was detected by means of a quantitative real-time PCR assay. Even after the cessation of CsA, the fever persisted and the peripheral atypical lymphocytes proliferated rapidly. The patient suffered from respiratory failure, liver dysfunction, and metabolic acidosis. Rituximab was administered without success and he died.

Graves disease following rabbit antithymocyte globulin treatment of severe aplastic anemia in a Korean child

Antithymocyte globulin (ATG) is used as an immunosuppressive treatment (IST) to deplete clonal suppressor T cells in patients with severe aplastic anemia (SAA). The depletion of suppressor T cells by ATG may affect the activation of B cells, which results in an increased risk for autoimmune conditions. A 12-year-old boy was diagnosed with idiopathic SAA. As he did not have an human leukocyte antigen-matched sibling, he was treated with rabbit ATG (3.5 mg/kg/day for 5 days) and cyclosporine. Five months later, he became transfusion independent. However, 23 months after IST, he complained of mild hand tremors, sweating, weight loss, palpitations, and goiter. Results of thyroid function tests revealed hyperthyroidism (free thyroxine, 3.42 ng/dL; thyroid stimulating hormone [TSH], <0.01 nIU/mL; triiodothyronine, 3.99 ng/mL). Results of tests for autoantibodies were positive for the antimicrosome antibody and TSH-binding inhibitory immunoglobulin, but negative for the antithyroglobulin antibody and antinuclear antibody. He was treated with methimazole, and his symptoms improved. The patient has been disease free for 39 months after IST and 9 months after methimazole treatment. This case report suggests that although rare, rabbit ATG may have implications in the pathogenesis of autoimmune hyperthyroidism. Our findings suggest that thyroid function tests should be incorporated in the routine follow-up of SAA patients treated with ATG.

Anti-thymocyte globulin could improve the outcome of allogeneic hematopoietic stem cell transplantation in patients with highly aggressive T-cell tumors

The early experiment result in our hospital showed that anti-thymocyte globulin (ATG) inhibited the proliferation of lymphoid tumor cells in the T-cell tumors. We used the ATG as the part of the conditioning regimen and to evaluate the long-term anti-leukemia effect, the safety and complication in the patients with highly aggressive T-cell lymphomas. Twenty-three patients were enrolled into this study. At the time of transplant, six patients reached first or subsequent complete response, three patients had a partial remission and 14 patients had relapsed or primary refractory disease. The conditioning regimen consisted of ATG, total body irradiation, toposide and cyclophosphamide. The complete remission rate after transplant was 95.7%. At a median follow-up time of 25 months, 16 (69.6%) patients are alive and free from diseases, including nine patients in refractory and progressive disease. Seven patients died after transplant, five from relapse and two from treatment-related complications. The incidence of grades II–IV acute graft-vs-host disease (GvHD) was 39.1%. The maximum cumulative incidence of chronic GvHD was 30%. The most frequent and severe conditioning-related toxicities observed in 8 out of 23 patients were grades III/IV infections during cytopenia. Thus, ATG-based conditioning is a feasible and effective alternative for patients with highly aggressive T-cell tumors.

Successful treatment of Rituximab-resistant Epstein-Barr virus-associated post-transplant lymphoproliferative disorder using R-CHOP

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorder (EBV-PTLD) is a complication of hematopoietic stem cell transplantation (HSCT). Standard initial treatment of patients with EBV-PTLD includes administration of rituximab or dose reduction of a calcineurin inhibitor. We report successful chemotherapeutic treatment of rituximab-resistant EBV-PTLD after HSCT in a patient with severe aplastic anemia (AA). A 38-year-old woman with antithymocyte globulin (ATG)-resistant severe AA received bone marrow transplantation from an unrelated donor (human leukocyte antigen-DR single-locus mismatch). The conditioning regimen included fludarabine, cyclophosphamide, ATG, and total body irradiation, and prophylaxis for graft-versus-host disease consisted of short methotrexate and tacrolimus. Neutrophil engraftment occurred on day 21. Left cervical lymph node swelling was observed after day 45, and analysis of a biopsy specimen revealed EBV-PTLD and a high blood EBV load (56,000 copies). The patient was treated with rituximab 4 times per week, but the lymphadenopathy continued and the blood EBV load increased to 96,000 copies. Half-dose treatment with rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisolone (R-CHOP) was initiated on day 71. After 32 days of treatment with R-CHOP, the patient's neutrophil level was restored to > 0.5 × 10(9)/L and both the lymphadenopathy and the blood EBV load (< 100 copies) were rapidly reduced. Although chemotherapy is not preferred soon after HSCT, it may be an effective strategy for treating patients with rituximab-resistant EBV-PTLD.

Response-guided therapy for steroid-refractory acute GVHD starting with very-low-dose antithymocyte globulin

Treatment for steroid-refractory acute graft-versus-host disease (GVHD) has not been established yet. In this article, we report a single-center experience with rabbit antithymocyte globulin (ATG) for the treatment of steroid-refractory acute GVHD. We retrospectively analyzed 11 consecutive patients between December 2009 and December 2013. ATG was given at an initial dose of 1.0 mg/kg for all but one patient with gradual dose escalation while assessing responses. The overall improvement at day 28 was 55% after a median of two treatments (range: 1-5), and a median dose of 3 mg/kg (range: 1.0-11.75 mg/kg) of ATG. Patients with skin (100%, 3/3) and gut (83%, 5/6) responded favorably, whereas the cases with liver involvement showed poor responses (25%, 1/4). The overall survival and transplant-related mortality at 1 year were 55% and 45%, respectively. There were no patients who had developed a post-transplant lymphoproliferative disorder. We suggest that response-guided ATG therapy could be an option for patients with steroid-refractory GVHD, without increasing the incidence of opportunistic infections.

Successful Allogeneic Stem Cell Transplantation for Severe Aplastic Anemia after Treatment of Lymphoproliferative Disorder Caused by Rabbit Antithymocyte Globulin

Immunosuppressive therapy (IST) with a combination of antithymocyte globulin (ATG) and cyclosporine (CsA) is an effective therapeutic modality for patients with aplastic anemia (AA) who are not eligible for allogeneic stem cell transplantation (Allo-SCT) from a human leukocyte antigen-identical sibling donor. However, there have been reports of some patients developing lymphoproliferative disorder (LPD) after IST for AA. We herein report a case of a 26-year-old man with severe AA (SAA) complicated by LPD after a single course of IST, who was successfully treated with Allo-SCT from an unrelated donor. Two months after starting IST for SAA, he developed LPD in the stomach. CsA was reduced, however, his neutrophil counts decreased, and CsA could not be discontinued. The patient was treated with rituximab monotherapy, and LPD resulted in complete remission. However, he failed IST for SAA and underwent Allo-SCT with reduced-intensity conditioning to recover his hematopoiesis. The patient has achieved complete hematopoietic recovery without the recurrence of LPD for five years after transplantation. This is the first report of successful Allo-SCT for SAA after the treatment of LPD caused by the use of rabbit ATG. This case provides useful information for the management of SAA with the development of LPD after IST.

Ileal mass-like lesion induced by Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in a patient with aplastic anemia

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening hyperinflammatory syndrome characterized by activated macrophages engulfing erythrocytes, leukocytes, platelets, and their precursor cells in bone marrow, liver, spleen, or lymph nodes. We report a case of Epstein-Barr virus (EBV)-associated HLH unusually presenting as an ileal mass. A 23-year-old man presented initially with persistent fever unresponsive to antibiotics and pancytopenia. A bone marrow aspiration and biopsy were used to diagnose the patient with aplastic anemia and HLH. A relatively well-defined low-density mass was radiologically noted in the terminal ileum, along with enlarged lymph nodes, and was suspected to be malignant lymphoma or an abscess. The ileocecectomy specimen revealed a transmural hemorrhagic infarction with numerous activated macrophages phagocytosing erythrocytes, plasma cells, and lymphocytes, and he was diagnosed with EBV-associated HLH. The patient received an allo-unrelated peripheral blood stem-cell transplantation and expired due to graft-versus-host disease following liver failure. The present case is very unique, in that EBV-associated HLH presented with an unusual ileal mass resulting from hemorrhagic infarction in a patient with aplastic anemia, suggesting variability in the biological behavior of EBV-associated disease.