Clinical observation of low-dose combination chemotherapy in refractory/recurrent paroxysmal nocturnal hemoglobinuria patients: A single-center retrospective analysis.

BACKGROUND: We performed a retrospective analysis to investigate the clinical characteristics and therapeutic strategies of 20 refractory/recurrent PNH patients, including the clinical efficacy of chemotherapy treatment, safety, and survival. METHODS: The clinical data of 20 classic PNH patients who were refractory/recurrent or had glucocorticoid dependence in our hospital were analyzed, including clinical manifestations, laboratory examinations, treatment efficacy, and survival. RESULTS: Seventeen patients had a marked improvement in anemia after chemotherapy, 14 patients acquired blood transfusion independence, and the Hb of 3 patients increased to normal levels. Although 6 patients still needed blood transfusion, the transfusion interval was significantly prolonged. The percentages of LDH, TBIL, and RET, which are indicators of hemolysis, were significantly lower than those before chemotherapy. The dosage of adrenal glucocorticoids was reduced by more than half compared with that before chemotherapy. CONCLUSIONS: Chemotherapy can reduce PNH clones, promote normal hematopoiesis, and control hemolytic attack. It is a promising and widely used therapeutic method.

Outcome of allogeneic hematopoietic stem cell transplantation in adult patients with paroxysmal nocturnal hemoglobinuria.

The safety and efficacy of allogeneic hematopoietic stem cell transplantation (HSCT) for paroxysmal nocturnal hemoglobinuria (PNH) remain unclear. Therefore, we retrospectively analyzed the outcomes of 42 adult patients with PNH who underwent allogeneic HSCT using the registry database of the Japan Society for Hematopoietic Cell Transplantation. The median patient age was 32.5 years. The number of packed red cell (PRC) transfusions was < 20 times in 19 patients and ≥ 20 times in 16; 7 patients had missing data. Stem cell sources were bone marrow (N = 15) or peripheral blood (N = 13) from a related donor or bone marrow (N = 11) and cord blood (N = 3) from an unrelated donor. The cumulative incidence of neutrophil engraftment at day 40 was 81%. Six patients died before engraftment, and the 6-year overall survival (OS) was 74%. The OS of patients with < 20 pretransplant PRC transfusions was significantly higher than that of patients with ≥ 20 pretransplant PRC transfusions (95% vs. 63%; P < 0.05). Moreover, the OS of patients aged < 30 years was significantly higher than that of patients aged ≥ 30 years (90% vs. 59%; P < 0.05). Allogeneic HSCT for PNH could provide favorable survival; however, pretransplant transfusion burden and patient age should be considered when deciding the timing of allogeneic HSCT.

Paroxysmal nocturnal hemoglobinuria: current treatments and unmet needs.

The current standard of care for paroxysmal nocturnal hemoglobinuria (PNH) are the C5 inhibitors eculizumab and ravulizumab, both monoclonal antibodies designed to target the complement protein C5, thereby preventing its cleavage and the formation of the terminal attack complex. C5 inhibitors have yielded substantial improvements in the treatment of PNH and changed the mortality and morbidity, as well as health-related quality of life of patients with the disease. These treatments target underlying intravascular hemolysis; however, they do not address extravascular hemolysis, resulting in incomplete response and remaining symptoms in some patients. Therefore, despite treatment with a C5 inhibitor, some patients still experience anemia with associated fatigue, transfusion needs, and impaired health-related quality of life. DISCLOSURES: This research was developed under a research contract between RTI Health Solutions and Apellis Pharmaceuticals and was funded by Apellis Pharmaceuticals. Bektas, Copley-Merriman, and Khan are employees of RTI Health Solutions. Sarda is an employee of Apellis Pharmaceuticals. Shammo consults for Apellis Pharmaceuticals.

Hematopoietic Cell Transplantation for Paroxysmal Nocturnal Hemoglobinuria in the Age of Eculizumab.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired clonal hematopoietic cell disease characterized by the destruction of hematopoietic cells through activation of the complement system with manifestations that can be life-threatening including hemolysis, thrombosis, and marrow failure. Allogeneic hematopoietic cell transplantation (HCT) remains the sole cure for PNH, but eculizumab, a terminal complement inhibitor of C5, has been used to prevent complement-mediated hemolysis in patients with PNH since its approval by the Food and Drug Administration in 2007. We examined outcomes of HCT in patients with PNH to evaluate the effects of disease subtype, conditioning intensity, and eculizumab use either pre-HCT or post-HCT. Fifty-five patients with a diagnosis of PNH underwent at least 1 HCT, with 4 patients requiring a second HCT for graft failure. The median age at the time of first HCT was 30.0 years (range, 4.2 to 66.9 years). Seventeen patients (30.9%) had classical PNH, and the remaining 38 patients had PNH associated with another marrow disorder (aplastic anemia in 26 of the 38). Indications for HCT included pancytopenia in 47.3% of the patients, myeloid malignancy (myelodysplastic syndrome, myeloproliferative neoplasm, or acute myelogenous leukemia) in 21.8%, recurrent hemolysis in 20.0%, and thrombosis in 10.9%. Of the 55 first HCTs, 26 were performed with myeloablative conditioning, 27 were performed with reduced-intensity conditioning, and 2 sets of identical twins underwent HCT without any conditioning. Donor types included HLA-matched related in 38.2%, HLA-matched unrelated in 34.5%, single HLA-allele mismatched unrelated in 16.4%, umbilical cord blood in 5.5%, syngeneic in 3.6%, and HLA-haploidentical in 1.8%. The median duration of follow-up in surviving patients was 6.1 years (range, 2.1 to 46.1 years) after first HCT. The median time to neutrophil and platelet engraftment was 17 days and 19 days, respectively; all but 2 patients (96.3%) had sustained engraftment. Overall survival was 70% at 5 years. Neither the choice of conditioning intensity nor PNH subtype affected survival. Nineteen patients died during follow-up, including 12 patients before day +365. Six patients received treatment with eculizumab before HCT, and 2 were treated after HCT. All patients treated with eculizumab were alive at a median follow-up of 2.3 years (range, .2 to 6.9 years). Both patients treated with eculizumab after HCT had minimal to no acute GVHD (aGVHD), with grade I skin aGVHD in 1 patient and no aGVHD in the other patient, and no chronic GVHD at 2.1 and 4.1 years post-HCT, respectively. With the approval of eculizumab, the indications for HCT include persistent hemolysis, persistent thrombosis, and associated marrow failure. Administration of eculizumab before and after HCT warrants further study, particularly considering our observation of minimal to no GVHD in 2 patients who received eculizumab after HCT.

The Hematopoietic Cell Transplant Comorbidity Index predicts survival after allogeneic transplant for nonmalignant diseases.

Despite improvements, mortality after allogeneic hematopoietic cell transplantation (HCT) for nonmalignant diseases remains a significant problem. We evaluated whether pre-HCT conditions defined by the HCT Comorbidity Index (HCT-CI) predict probability of posttransplant survival. Using the Center for International Blood and Marrow Transplant Research database, we identified 4083 patients with nonmalignant diseases transplanted between 2007 and 2014. Primary outcome was overall survival (OS) using the Kaplan-Meier method. Hazard ratios (HRs) were estimated by multivariable Cox regression models. Increasing HCT-CI scores translated to decreased 2-year OS of 82.7%, 80.3%, 74%, and 55.8% for patients with HCT-CI scores of 0, 1 to 2, 3 to 4, and ≥5, respectively, regardless of conditioning intensity. HCT-CI scores of 1 to 2 did not differ relative to scores of 0 (HR, 1.12 [95% CI, 0.93-1.34]), but HCT-CI of 3 to 4 and ≥5 posed significantly greater risks of mortality (HR, 1.33 [95% CI, 1.09-1.63]; and HR, 2.31 [95% CI, 1.79-2.96], respectively). The effect of HCT-CI differed by disease indication. Patients with acquired aplastic anemia, primary immune deficiencies, and congenital bone marrow failure syndromes with scores ≥3 had increased risk of death after HCT. However, higher HCT-CI scores among hemoglobinopathy patients did not increase mortality risk. In conclusion, this is the largest study to date reporting on patients with nonmalignant diseases demonstrating HCT-CI scores ≥3 that had inferior survival after HCT, except for patients with hemoglobinopathies. Our findings suggest that using the HCT-CI score, in addition to disease-specific factors, could be useful when developing treatment plans for nonmalignant diseases.

Cancer in the National Cancer Institute inherited bone marrow failure syndrome cohort after fifteen years of follow-up.

The National Cancer Institute Inherited Bone Marrow Failure Syndromes Cohort enrolls patients with the four major syndromes: Fanconi anemia, dyskeratosis congenita, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome, and follows them with a common comprehensive protocol. The current analysis includes more than double the numbers of patients and person-years since our first report, published in 2010. Patients with Fanconi anemia and dyskeratosis congenita developed head and neck and anogenital squamous cell carcinomas at rates that were hundreds-fold greater than those of the general population. In competing risk analyses the cumulative incidence of severe bone marrow failure, leading to stem cell transplantation or death, was more than 70% by age 60. Patients with Diamond-Blackfan anemia developed lung, colon, and cervical cancer at rates greater than those of the general population. The cumulative incidence of severe bone marrow failure in those with Diamond-Blackfan anemia was 50% by age 60. The smaller group, with Shwachman-Diamond syndrome, have not as yet developed a significant number of solid tumors, but 40% developed bone marrow failure by age 50. The risk of solid tumors following stem cell transplantation in Fanconi anemia and in dyskeratosis congenita was significantly higher than in non-transplanted patients. There was no clear association of genotype with cancer in any of the syndromes. Cancer was most common in Fanconi anemia, followed by dyskeratosis congenita; Diamond-Blackfan anemia and Shwachman-Diamond syndrome are less cancer-prone, but nonetheless all patients are at increased risks of bone marrow failure and specific cancers. clinicaltrials.gov Identifier: 00027274.

Outcomes of allogeneic stem cell transplantation in patients with paroxysmal nocturnal hemoglobinuria with or without aplastic anemia.

OBJECTIVE: The aim of this study was to evaluate the long-term outcomes of allogeneic stem cell transplantation (SCT) in patients with paroxysmal nocturnal hemoglobinuria (PNH) with or without aplastic anemia (AA). METHOD: A total of 33 patients with PNH clones who underwent allogeneic SCT were analyzed. RESULTS: After a median follow-up of 57 months (range, 6.0-151.3), the 5-year estimated overall survival rate was 87.9±5.7%. Four patients died of transplant-related mortality (TRM). With the exception of one patient with early TRM, 32 patients were engrafted. Two patients who had developed delayed GF received a second transplant and recovered. The cumulative incidences of acute graft-vs-host disease (GVHD) (≥grade II) and chronic GVHD (≥moderate) were 27.3±7.9% and 18.7±7.0%, respectively. Twenty-one patients receiving SCT with reduced-intensity conditioning (RIC) had available follow-up data for PNH cell population for the first 6 months post-transplant. Analysis of these data revealed that the PNH clones disappeared within approximately 2 months. CONCLUSION: RIC regimen was sufficient to eradicate PNH clones with sustained donor-type engraftment after allogeneic SCT. Therefore, application of allogeneic SCT with RIC should be considered in patients with PNH, in accordance with the severity of the underlying bone marrow failure.

Rapamycin is highly effective in murine models of immune-mediated bone marrow failure.

Acquired aplastic anemia, the prototypical bone marrow failure disease, is characterized by pancytopenia and marrow hypoplasia. Most aplastic anemia patients respond to immunosuppressive therapy, usually with anti-thymocyte globulin and cyclosporine, but some relapse on cyclosporine withdrawal or require long-term administration of cyclosporine to maintain blood counts. In this study, we tested efficacy of rapamycin as a new or alternative treatment in mouse models of immune-mediated bone marrow failure. Rapamycin ameliorated pancytopenia, improved bone marrow cellularity, and extended animal survival in a manner comparable to the standard dose of cyclosporine. Rapamycin effectively reduced Th1 inflammatory cytokines interferon-γ and tumor necrosis factor-α, increased the Th2 cytokine interleukin-10, stimulated expansion of functional regulatory T cells, eliminated effector CD8+ T cells (notably T cells specific to target cells bearing minor histocompatibility antigen H60), and preserved hematopoietic stem and progenitor cells. Rapamycin, but not cyclosporine, reduced the proportion of memory and effector T cells and maintained a pool of naïve T cells. Cyclosporine increased cytoplasmic nuclear factor of activated T-cells-1 following T-cell receptor stimulation, whereas rapamycin suppressed phosphorylation of two key signaling molecules in the mammalian target of rapamycin pathway, S6 kinase and protein kinase B. In summary, rapamycin was an effective therapy in mouse models of immune-mediated bone marrow failure, acting through different mechanisms to cyclosporine. Its specific expansion of regulatory T cells and elimination of clonogenic CD8+ effectors support its potential clinical utility in the treatment of aplastic anemia.

Clinical course and disease burden in patients with paroxysmal nocturnal hemoglobinuria by hemolytic status.

Disease characteristics of patients enrolled in the International PNH Registry were assessed during two follow-up periods based on hemolytic status while untreated with eculizumab: Non-hemolytic cohort: follow-up time defined as time from disease start until last reported untreated lactate dehydrogenase (LDH) value <1.5×upper limit normal (ULN); Hemolytic cohort: follow-up time defined as time from LDH ≥1.5×ULN at or post-disease start, to most recent untreated follow-up. A total of 1012 patients met criteria for the Non-hemolytic cohort and 1565 patients for the Hemolytic cohort; median (min, max) years of follow-up were 2.2 (0.0, 54.2) and 1.2 (0.0, 37.2) years, respectively. Annual rate of thrombotic events (TEs) was lower in the Non-hemolytic than Hemolytic cohort (0.01 events/person-year vs. 0.03 events/person-year; p<0.001). Mortality was lower in the Non-hemolytic cohort than the Hemolytic cohort (0.1% (1 death) vs. 1.8% (22 deaths); p<0.001). While elevated risks for TEs were observed in patients with hemolysis, many TEs were also observed in patients without hemolysis. As thrombosis is the leading cause of mortality in patients with PNH, this real-world analysis highlights the importance of awareness and monitoring for TEs in patients with PNH regardless of hemolytic status.

Changing prognosis in paroxysmal nocturnal haemoglobinuria disease subcategories: an analysis of the International PNH Registry.

BACKGROUND: Paroxysmal nocturnal haemoglobinuria (PNH) is a rare disease. Although much progress has been made in the understanding of the pathophysiology of the disease, far less is known with respect to the clinical outcomes of patients with PNH. Few retrospective studies provide survival estimates, and even fewer have explored the clinical heterogeneity of the disease. Haemolytic and aplastic anaemia (AA) forms of the disease have been recognised as main disease categories, with the haemolytic form being associated with the worst prognosis by the largest studied cohort some years ago. AIMS: To describe mortality and causes of death in PNH overall and by PNH classification and to evaluate risk factors associated with mortality. METHODS: We analysed data of 2356 patients enrolled in the International PNH Registry with multivariate analyses, using time-dependent covariates. Patients were classified into haemolytic, AA/PNH syndrome or intermediate PNH. RESULTS: Overall, 122 (5.2%) patients died after enrolment, the incidence according to subcategories being 5.1, 11.7, 2.0 and 4.8% for patients with haemolytic PNH, AA-PNH, intermediate and insufficient data respectively. Older age and decreased performance status also affected survival in multivariate analysis. Improved outcome of patients with haemolytic PNH suggests that eculizumab treatment in PNH may be associated with improved survival. CONCLUSION: A detailed analysis of clinical presentations and causes of death in patients with PNH, overall and by disease subcategories, provide evidence that in the current era, patients with haemolytic PNH are no longer those who harbour the worst prognosis. This finding differs sharply from what has been previously reported.

A comparative analysis of clinical characteristics of patients with paroxysmal nocturnal hemoglobinuria between Asia and Europe/America.

To accurately analyze the clinical characteristics of paroxysmal nocturnal hemoglobinuria (PNH) in different ethnic backgrounds, we retrieved all retrospective studies on clinical characteristics of PNH with a median follow-up period >60 months published after 2000, analyzed the clinical characteristics of PNH patients in Asia and European/America, and statistically compared enumeration data in these studies. We included 1665 patients in this analysis. The proportion of female patients in Asia was significantly lower than that in Europe/America (P = 0.000). Incidence rates of hemoglobinuria and thromboembolism in Asia were significantly lower than in Europe/America (both P values were 0.000). Within the subgroups of patients with thromboembolism, Asian patients had a higher proportion of arterial thrombosis while Western patients had a higher proportion of abdominal venous thrombosis. Bone marrow failure was not clearly defined in most studies. The proportion of patients with pancytopenia was higher in China than in France (P = 0.048). The total death rates were similar in both ethnic groups (P > 0.05). In Europe/America the major cause of death was thromboembolism and in Asian countries was serious infections. Differences in population characteristics of PNH patients among different ethnic groups indicate the possibility of differential pathogenesis and may be informative for treatment decisions.

Haploidentical hematopoietic stem cell transplant in paroxysmal nocturnal hemoglobinuria.

Eighteen patients with paroxysmal nocturnal hemoglobinuria (PNH) receiving allogeneic hematopoietic stem cell transplant (allo-HSCT), either from HLA-haploidentical donors (HRD; n = 10) or HLA-matched donors (n = 5 from siblings and n = 3 from unrelated donors), were retrospectively evaluated. One showed primary graft failure following unrelated-donor HSCT. He was given a second HRD-HSCT, but died from cytomegalovirus pneumonia after achieving hematopoietic recovery. The other 17 patients achieved sustained engraftment and full-donor chimerism. Four in the HRD-HSCT group experienced grade II/III acute graft-versus-host disease (aGVHD), and five in the HLA-matched HSCT group developed grade II aGVHD. Among all 18 patients, 10 developed chronic GVHD (cGVHD), only one patient receiving HRD-HSCT developed extensive cGVHD. Nine in the HRD-HSCT group and all those in the HLA-matched HSCT group were alive and transfusion-independent at last follow-up. Our findings suggest that allo-HSCT is a promising treatment for PNH, and HRD-HSCT is a viable option for patients with PNH who lack HLA-matched donors.

Predictive Factors of Mortality in Population of Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH): Results from a Korean PNH Registry.

Paroxysmal nocturnal hemoglobinuria (PNH) is a progressive, systemic, life-threatening disease, characterized by chronic uncontrolled complement activation. A retrospective analysis of 301 Korean PNH patients who had not received eculizumab was performed to systematically identify the clinical symptoms and signs predictive of mortality. PNH patients with hemolysis (lactate dehydrogenase [LDH] ≥ 1.5 × the upper limit of normal [ULN]) have a 4.8-fold higher mortality rate compared with the age- and sex-matched general population (P < 0.001). In contrast, patients with LDH < 1.5 × ULN have a similar mortality rate as the general population (P = 0.824). Thromboembolism (TE) (odds ratio [OR] 7.11; 95% confidence interval [CI] (3.052-16.562), renal impairment (OR, 2.953; 95% CI, 1.116-7.818) and PNH-cytopenia (OR, 2.547; 95% CI, 1.159-5.597) are independent risk factors for mortality, with mortality rates 14-fold (P < 0.001), 8-fold (P < 0.001), and 6.2-fold (P < 0.001) greater than that of the age- and sex-matched general population, respectively. The combination of hemolysis and 1 or more of the clinical symptoms such as abdominal pain, chest pain, or dyspnea, resulted in a much greater increased mortality rate when compared with patients with just the individual symptom alone or just hemolysis. Early identification of risk factors related to mortality is crucial for the management of PNH. This trial was registered at www.clinicaltrials.gov as NCT01224483.

Distinct subgroups of paroxysmal nocturnal hemoglobinuria (PNH) with cytopenia: results from South Korean National PNH Registry.

We retrospectively assessed the clinical characteristics of patients with paroxysmal nocturnal hemoglobinuria (PNH) according to severity of cytopenia. A total of 282 patients with hematological parameters assessed at the time of diagnosis of PNH were included. There were 24 patients with PNH/severe aplastic anemia (SAA) (at least two of the three criteria; hemoglobin ≤8 g/dL; absolute neutrophil count (ANC) <0.5 × 10(9)/L; platelet count <20 × 10(9)/L), 96 patients with PNH/aplastic anemia (AA) (at least two of the three criteria; hemoglobin ≤10 g/dL; ANC 0.5-1.5 × 10(9)/L; platelet count 20-100 × 10(9)/L), and 162 classic PNH patients. Compared with the classic PNH subgroup, the PNH/SAA subgroup had a significantly lower median granulocyte PNH clone size (26.7 vs. 51.0 %, P = 0.021) and lower incidence of lactate dehydrogenase ≥1.5 times the upper limit of normal (52.9 vs. 80.0 %, P = 0.049). The incidence of thromboembolism was similar in both subgroups. Overall survival was significantly lower in the PNH/SAA subgroup than in the classic PNH subgroup (P = 0.033). Our findings suggest that identification of patients with PNH/SAA at the time of diagnosis is important because of different clinical manifestations and poorer outcome compared with patients with classic PNH (clinicaltrials.gov identifier: #NCT01224483).

Two consecutive pregnancies in a patient with paroxysmal nocturnal haemoglobinuria treated with anticoagulant therapy at different doses.

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired disorder of haematopoietic stem cells characterized by intravascular haemolysis, cytopenias and thrombophilia. Thrombophilia is the leading cause of mortality in patients with PNH. As the risk of thrombogenesis further increases during pregnancy and the postpartum period, an anticoagulant therapy is generally recommended for pregnant women with PNH. However, there are no standardized criteria for determining the appropriate dose of anticoagulant therapy. We describe the case of a PNH patient with who was managed with anticoagulant therapy at different doses during two consecutive pregnancies. A prophylactic dose of heparin was administered during her first pregnancy and a therapeutic dose, during her second pregnancy. Both pregnancies resulted in uncomplicated vaginal deliveries without thrombosis. Interestingly, not only D-dimer (as a thrombotic marker) but also lactate dehydrogenase (as a haemolytic marker) levels were lower during her second pregnancy when a therapeutic dose of heparin was used.

Impact of eculizumab treatment on paroxysmal nocturnal hemoglobinuria: a treatment versus no-treatment study.

Intravascular hemolysis in Paroxysmal nocturnal hemoglobinuria (PNH) can effectively be controlled with eculizumab, a humanized monoclonal antibody that binds complement protein C5. We report here a retrospective comparison study between 123 patients treated with eculizumab in the recent period (>2005) and 191 historical controls (from the French registry). Overall survival (OS) at 6 years was 92% (95%CI, 87 to 98) in the eculizumab cohort versus 80% (95%CI 70 to 91) in historical controls diagnosed after 1985 (HR 0.38 [0.15 to 0.94], P = 0.037). There were significantly fewer thrombotic events (TEs) in the group of patients treated with eculizumab (4% [1-10]) as compared to the historical cohort (27% [20-34]). However, we found that TEs may still occur after the initiation of eculizumab treatment and that previous TEs still have a negative impact on survival. Evolutions to myelodysplastic syndrome or acute leukemia were similar in both cohorts. There was less evolution to aplastic anemia in the treatment group. In multivariate analysis, absence of a previous TE and treatment with eculizumab were associated with a better OS. Treatment with eculizumab improves overall survival in classic PNH patients without increasing the risk of clonal evolution.

Loss of c-Kit and bone marrow failure upon conditional removal of the GATA-2 C-terminal zinc finger domain in adult mice.

Heterozygous mutations in the transcriptional regulator GATA-2 associate with multilineage immunodeficiency, myelodysplastic syndrome (MDS), and acute myeloid leukemia (AML). The majority of these mutations localize in the zinc finger (ZnF) domains, which mediate GATA-2 DNA binding. Deregulated hematopoiesis with GATA-2 mutation frequently develops in adulthood, yet GATA-2 function in the bone marrow remains unresolved. To investigate this, we conditionally deleted the GATA-2 C-terminal ZnF (C-ZnF) coding sequences in adult mice. Upon Gata2 C-ZnF deletion, we observed rapid peripheral cytopenia, bone marrow failure, and decreased c-Kit expression on hematopoietic progenitors. Transplant studies indicated GATA-2 has a cell-autonomous role in bone marrow hematopoiesis. Moreover, myeloid lineage populations were particularly sensitive to Gata2 hemizygosity, while molecular assays indicated GATA-2 regulates c-Kit expression in multilineage progenitor cells. Enforced c-Kit expression in Gata2 C-ZnF-deficient hematopoietic progenitors enhanced myeloid colony activity, suggesting GATA-2 sustains myelopoiesis via a cell intrinsic role involving maintenance of c-Kit expression. Our results provide insight into mechanisms regulating hematopoiesis in bone marrow and may contribute to a better understanding of immunodeficiency and bone marrow failure associated with GATA-2 mutation.

Clinical Utility of Computed Tomography and Magnetic Resonance Imaging for Diagnosis of Posterior Reversible Encephalopathy Syndrome after Stem Cell Transplantation in Children and Adolescents.

Posterior reversible encephalopathy syndrome (PRES) is a clinical syndrome characterized by vision changes, altered mental status, and seizures, typically caused by an acute rise in blood pressure. PRES has been reported after hematopoietic stem cell transplantation (HSCT) in association with hypertension from calcineurin inhibitors and corticosteroids. The imaging evaluation of PRES after HSCT in children and young adults has not been well described. We performed a retrospective review of all HSCT recipients presenting to the intensive care unit with new neurologic symptoms. A neuroradiologist reviewed all radiologic images and compared computed tomography (CT) versus magnetic resonance imaging (MRI) findings indicative of diagnosis of PRES. Alternative imaging diagnoses explaining the patients' symptoms were also recorded. Fifty-four transplant recipients were admitted to the intensive care unit with new neurologic symptoms. Thirty-nine percent (21 of 54) of subjects had imaging findings consistent with PRES, 24% (13 of 54) had imaging findings consistent with an alternative diagnosis, 9% (5 of 54) had a nonspecific finding, and 28% (15 of 54) had no acute imaging findings. PRES was diagnosed at a median of 49 days (interquartile range, 29 to 94) after HSCT. The presenting symptom for the majority of patients with PRES was seizures (86%), whereas 14% presented with acute encephalopathy. Ninety-five percent of subjects diagnosed with PRES (20 of 21) underwent a head CT as their initial imaging evaluation. CT scan was diagnostic of PRES in 40% (8 of 20). Subsequently, 16 patients underwent brain MRI with 12 additional patients being diagnosed with PRES on MRI. The median time elapsed between negative CT and a positive MRI examination was 20 hours (range, 3.6 hours to 9 days). CT serves as an excellent screening test for acute pathology, such as intracranial hemorrhage; however, it lacks sensitivity for the diagnosis of PRES. Patients with clinical symptoms suggestive of PRES who have a negative CT should be treated appropriately for PRES and should undergo MRI of the brain as soon as clinically stable to confirm the diagnosis.

Histologic Features of Intestinal Thrombotic Microangiopathy in Pediatric and Young Adult Patients after Hematopoietic Stem Cell Transplantation.

High-risk transplantation-associated thrombotic microangiopathy (TMA) can present with multisystem involvement and is associated with a poor outcome after hematopoietic stem cell transplantation (HSCT), with < 20% 1-year survival. TMA may involve the intestinal vasculature and can present with bleeding and ischemic colitis. There are no established pathologic criteria for the diagnosis of intestinal TMA (iTMA). The goal of our study was to identify histologic features of iTMA and describe associated clinical features. We evaluated endoscopic samples from 50 consecutive HSCT patients for 8 histopathologic signs of iTMA and compared findings in 3 clinical groups based on the presence or absence of systemic high-risk TMA (hrTMA) and the presence or absence of clinically staged intestinal graft-versus-host disease (iGVHD): TMA/iGVHD, no TMA/iGVHD, and no TMA/no iGVHD. Thirty percent of the study subjects had a clinical diagnosis of systemic hrTMA. On histology, loss of glands, intraluminal schistocytes, intraluminal fibrin, intraluminal microthrombi, endothelial cell separation, and total denudation of mucosa were significantly more common in the hrTMA group (P < .05). Intravascular thrombi were seen exclusively in patients with hrTMA. Mucosal hemorrhages and endothelial cell swelling were more common in hrTMA patients but this difference did not reach statistical significance. Patients with hrTMA were more likely to experience significant abdominal pain and gastrointestinal bleeding requiring multiple blood transfusions (P < .05). Our study shows that HSCT patients with systemic hrTMA can have significant bowel vascular injury that can be identified using defined histologic criteria. Recognition of these histologic signs in post-transplantation patients with significant gastrointestinal symptoms may guide clinical decisions.

Clinical features and survival of asian pediatric patients with paroxysmal nocturnal hemoglobinuria: results from a single center in China.

OBJECTIVE: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease, especially in children. To characterize the clinical presentations and survival, we performed a retrospective analysis of pediatric patients. METHODS: We reviewed 55 pediatric patients with PNH referred to our hospital from January 1990 through June 2012 to assess clinical presentations, survival, and differences among subcategories. RESULTS: The overall survival 10 years after diagnosis estimated via the Kaplan-Meier method was 77.6%. The cohort of patients was divided into subcategories of classic PNH, PNH/aplastic anemia (AA), and subclinical PNH (PNH-sc)/AA based on the recently proposed PNH working clinical classification. We found that patients with classic PNH and PNH/AA had larger PNH clones and many more parameters of hemolysis, but patients with PNH-sc/AA had smaller PNH clones, fewer parameters of hemolysis, and a higher rate of bone marrow failure. Our results revealed a high rate of bone marrow failure and a low rate of hemoglobinuria at presentation. Furthermore, thrombotic events were not observed in our patients, which is significantly different from the rate seen in Caucasian patients. Additionally, pediatric patients with PNH may develop bone marrow cytogenetic abnormalities. CONCLUSION: This study provides insight into Chinese pediatric PNH patients and may aid in setting up individualized therapeutic regimens.