Aplastic Anemia In Children Research Articles

Epidemiology and Clinical Long-term Outcome of Childhood Aplastic Anemia in Korea for 15 Years

Aplastic anemia (AA) is a rare hematologic disease characterized by pancytopenia and hypocellular marrow. The Korean Society of Pediatric Hematology Oncology investigated retrospectively the incidence, survival, and transfusion independency according to treatment strategies in AA. All the questionnaires were sent to members for medical records. We collected and analyzed 702 available data. The male and female ratio was 1.2, and the median age at diagnosis was 9.3 years. The annual incidence of Korean children with AA was 5.16 per million per year. Constitutional anemia was diagnosed in 44 children. In acquired AA, causes were identified in 39 children. Severe AA (SAA) at initial diagnosis was more common than nonsevere AA. The overall survival was 47.8% with supportive care, 68.1% with immunosuppressive therapy (IST), and 81.8% with hematopoietic stem cell transplantation. In IST, response rate was 65.7%, and relapse rate after response was 54.4% within a median of 23.0 months. The factors with overall survival were severity of disease in supportive care, severity and response in IST, donor type, graft failure, and posttransplant events in hematopoietic stem cell transplantation. Long-term outcome in AA was dependent on treatment strategies. These Korean results may help research and prospective international clinical trials for childhood AA.

Relapse of aplastic anemia in children after immunosuppressive therapy: a report from the Japan Childhood Aplastic Anemia Study Group

Although the therapeutic outcome of acquired aplastic anemia has improved markedly with the introduction of immunosuppressive therapy using antithymocyte globulin and cyclosporine, a significant proportion of patients subsequently relapse and require second-line therapy. However, detailed analyses of relapses in aplastic anemia children are limited. We previously conducted two prospective multicenter trials of immunosuppressive therapy for children with aplastic anemia: AA-92 and AA-97, which began in 1992 and 1997, respectively. In this study, we assessed the relapse rate, risk factors for relapse, and the response to second-line treatment in children with aplastic anemia treated with antithymocyte globulin and cyclosporine. From 1992 to 2007, we treated 441 children with aplastic anemia with standard immunosuppressive therapy. Among the 264 patients who responded to immunosuppressive therapy, 42 (15.9%) relapsed. The cumulative incidence of relapse was 11.9% at 10 years. Multivariate analysis revealed that relapse risk was significantly associated with an immunosuppressive therapy regimen using danazol (relative risk, 3.15; P=0.001) and non-severe aplastic anemia (relative risk, 2.51; P=0.02). Seventeen relapsed patients received additional immunosuppressive therapy with antithymocyte globulin and cyclosporine. Eight patients responded within 6 months. Seven of nine non-responders to second immunosuppressive therapy received hematopoietic stem cell transplantation and five are alive. Eleven patients underwent hematopoietic stem cell transplantation directly and seven are alive. In the present study, the cumulative incidence of relapse at 10 years was relatively low compared to that in other studies mainly involving adult patients. A multicenter prospective study is warranted to establish optimal therapy for children with aplastic anemia.

Treatment of childhood aplastic anemia with antithymocyte globulin, management of side effects and long-term follow-up

To evaluate the efficacy of antithymocyte globulin (ATG) based immunosuppression therapy for childhood aplastic anemia, to reduce the adverse effects and to observe the long-term outcome. Thirty-five children with aplastic anemia (AA) were enrolled in this study. Six of the cases had very severe AA (VSAA), 11 had severe AA (SAA)-I, 8 had SAA-II and 10 had moderate AA (MAA). All these patients were treated with ATG plus Cyclosporin A (CSA). The following measures were taken during the ATG therapy: infection of the patients had been controlled before ATG treatment. Comprehensive anti-allergic measures were implemented. Close attention was paid to the hemorrhage related with platelet reduction caused by ATG and severe infection of the patients. Shortly after the ATG usage, all the patients had a significant decrease of absolute peripheral lymphoblast count by more than 60 percent. With a mean follow-up time of 28 months, the total effective rate was 77.14% (27/35), significant response rate was 57.14%(20/35). There was no significant difference among VSAA, SAA and MAA groups in the response rate. Adverse reactions included the following: (1) 48.6% (17/35) patients presented mild anaphylactoid reaction during the first day of ATG treatment; (2) 42.9%(15/35) cases presented serum sickness 5 - 11 days after the last dose of ATG with a mean duration of 3.6 days, all the patients were cured effectively with methylprednisolone; (3) 25.7% (9/35) patient's peripheral blood platelet count was reduced, might be caused by ATG, to below 10 × 10(9)/L, but no patient had severe hemorrhagic complication after platelet transfusion was performed; (4) 22.9%(8/35)of patients got infection within a month after ATG therapy, including 3 cases with clinical septicemia, all the 3 cases recovered after antibiotics treatment. There was no ATG treatment-related death in this series. ATG is a very effective therapy for children with SAA and MAA. Comprehensive measures are needed to prevent and handle the side effects to avoid treatment-related death. Long-term supportive therapy and proper follow up contribute to the favourable outcomes of the patients.

Outcome of 64 Aplastic Anemia Children With Allogenic Hematopoietic Stem Cell Transplant in China: A Report From Chinese Pediatric Group of HSCT

Outcome of 64 Aplastic Anemia Children With Allogenic Hematopoietic Stem Cell Transplant in China: A Report From Chinese Pediatric Group of HSCT

Predicting response to immunosuppressive therapy in childhood aplastic anemia

In aplastic anemia, predictive markers of response to immunosuppressive therapy have not been well defined. We retrospectively evaluated whether clinical and laboratory findings before treatment could predict response in a pediatric cohort from the multicenter AA-97 study in Japan. Between 1997 and 2006, 312 newly diagnosed children were enrolled and treated with a combination of antithymocyte globulin and cyclosporine. In multivariate analyses, lower white blood cell count was the most significant predictive marker of better response; patients with white blood cell count less than 2.0×10(9)/L showed a higher response rate than those with white blood cell count of 2.0×10(9)/L or more (P=0.0003), followed by shorter interval between diagnosis and therapy (P=0.01), and male sex (P=0.03). In conclusion, pre-treatment clinical and laboratory findings influence response to therapy. The finding that response rate worsens with increasing interval between diagnosis and treatment highlights the importance of prompt immunosuppressive therapy for patients with aplastic anemia.

Allogeneic hematopoietic stem cell transplantation for childhood aplastic anemia: Prospective trial in China

We aim to investigate the efficacy and safety of the treatment with fully matched allogeneic hematopoietic stem cell transplants for children with severe aplastic anemia (SAA) in the first prospective trial in China. Six SAA children received allogeneic hematopoietic stem cell transplantation combined with chemotherapy. Five patients had successful engraftment while the sixth child regained normal peripheral blood counts consistent with spontaneous autologous hematopoiesis. Mean duration of follow-up was 2.75 years, and survival was 83%(5/6). The results indicated that allogeneic hematopoietic stem cell transplantation is a good option for the treatment of children with severe aplastic anemia.

Environmental lead exposure as a risk for childhood aplastic anemia

Concern about environmental lead exposure as a significant public health threat has increased as evidence has accumulated regarding adverse health effects at successively lower levels. Aplastic anemia is a hematological disorder of unknown etiology with a high lethality rate. Lead is a known toxicant for the hematopoietic system. Oxidative stress appears to be the possible mode of lead toxicity. We evaluated the effects of blood lead level on oxidative stress parameters in children suffering from aplastic anemia disease. Seventeen children with aplastic anemia disease (15 male and 2 female, age 3-12 y) were recruited in the study group. Fifty one healthy children (45 male and 6 female, age 3-12 y) having normal blood profiles and not suffering from any chronic disease(s) were used as controls. Blood lead level and oxidative stress parameters were determined. Mean blood lead level was significantly higher while δ-aminolevulinic acid dehydratase (δ-ALAD) activity, a biomarker for lead exposure was significantly lower in the study group as compared to the control group (p < 0.05 for each). Thiobarbituric acid reactive species (TBARS), a marker of lipid peroxidation, was significantly higher while the antioxidant glutathione (GSH) level was significantly lower in the study group as compared to the control group (p < 0.05 for each). Activity of the antioxidant enzyme catalase (CAT) was significantly higher in the study group than in the control group (p < 0.05). There was a significant negative correlation of blood lead levels with δ-ALAD (r = -0.45; p < 0.05) and GSH (r = -0.32; p < 0.05), and a positive correlation with TBARS (r = 0.41; p < 0.05) and CAT (r = 0.37; p < 0.05). Although a causal pathway cannot be determined from this study, our results indicated that lead induces oxidative stress in children suffering from aplastic anemia. Lead-induced oxidative stress as an underlying mechanism for aplastic anemia warrants further research.

Bone marrow findings of childhood aplastic anemia: analyses of 140 cases by central reviewers

Bone marrow findings of childhood aplastic anemia: analyses of 140 cases by central reviewers

Artefactual elevation of creatinine due to creatine water supplements

We report the case of a 20-year-old man who suffered an artefactual elevation of creatinine after consuming a creatine water supplement. Before this event, the patient was regularly seen in our clinic to monitor progression of a secondary paroxysmal nocturnal haemoglobinuria clone complicating childhood aplastic anaemia, for which he was previously treated with immunosuppression. Aside from his asymptomatic, stable, moderate thrombocytopenia (platelet count, 50-60 × 10 9 /L), there had never been evidence of haemolysis or thrombosis. The patient took no regular prescription medications and had previously documented normal renal function (Table). Blood tests performed 1 day before the patient's admission to hospital showed a significantly elevated creatinine level of 196 μmol/L (reference range, 40-120 μmol/L), with an estimated glomerular filtration rate of 38 mL/min, calculated using the MDRD (modification of diet in renal disease) formula. 1 The patient reported no recent systemic illnesses or symptoms. However, on specific questioning, he reported using a creatine water supplement at 1.0-2.5 L/day for the previous 2-3 months— an intake greater than that recommended in the product packaging information (3 g creatine in 500 mL of water daily). Physical examination was unremarkable and fluid status was clinically euvolaemic. The patient was admitted to hospital for investigation of apparent acute renal dysfunction. Repeat blood tests confirmed a disproportionately elevated creatinine level of 206 μmol/L relative to the urea level, which was normal (6.9 mmol/L; reference range, 2.1-7.1 mmol/L). All electrolyte levels were within normal limits, including a potassium level of 4.1 mmol/L. A full blood count examination demonstrated stable thrombocytopenia with a platelet count of 58 x 10 9 /L. Other parameters, including glycated haemoglobin level, white cell count and neutrophil count, fell within their reference ranges. Results of further directed investigations did not show any significant abnormalities to account for the apparent renal impairment. These included a total protein level of 82 g/L, an albumin level of 47 g/L, and a creatine kinase level of 331 U/L. Although above the reference range, at this level the creatine kinase would not be associated with elevated creatinine. Also within reference range were the patient's levels of negative antinuclear antibodies, extractable nuclear antigens, anti-double-stranded DNA, antinuclear cytoplasmic antibodies, antiglomerular basement membrane antibody, antistreptolysin serology, HIV, and hepatitis B and C serology. Midstream urine analysis was unremarkable, being within the reference range for cells, casts, protein and myoglobin. Renal tract ultrasound with Doppler studies showed normal-sized kidneys with no evidence of renal artery or vein thrombosis, or obstruction. The patient was initially treated with intravenous normal saline and cessation of the creatine water supplement. Further blood tests performed 2.5 hours later showed a reduction in his creatinine level to 152 μmol/L; and those performed 17 hours later showed that the level had normalised to 81 μmol/L. In view of the rapid return to a normal creatinine level, a renal biopsy was not performed. The patient was clinically well throughout his hospital stay and, since discharge, has experienced normal renal function.

Susceptibility Pathways in Fanconi's Anemia and Breast Cancer

The study of rare genetic diseases can lead to insights into the cause and treatment of common diseases. An example is the rare chromosomal instability disorder, Fanconi Anemia (FA). Studies of this disease have elucidated general mechanisms of bone marrow failure, cancer pathogenesis, and resistance to chemotherapy. The principal features of FA are aplastic anemia in childhood, susceptibility to cancer or leukemia, and hypersensitivity of FA cells to DNA cross-linking agents. There are thirteen FA genes, and one of these genes is identical to the well known breast cancer susceptibility gene, BRCA2. The corresponding FA proteins cooperate in the recognition and repair of damaged DNA. Inactivation of FA genes occurs not only in FA patients but also in a variety of cancers in the general population. These findings have broad implications for predicting the sensitivity and resistance of tumors to conventional anti-cancer agents, to inhibitors of poly-ADP ribose polymerase 1, an enzyme involved in DNA repair, and to other inhibitors of DNA repair.

Successful Treatment of Esophageal Squamous Cell Carcinoma in a Patient with Fanconi Anemia

Fanconi anemia is a congenital syndrome characterized by hypoplasia of bone marrow and the development of aplastic anemia in childhood, followed by myelodysplastic syndrome and acute myelogenous leukemia in later life. We report here a patient first diagnosed with Fanconi anemia at age 10. Bone marrow transplantation was performed at age 23 and repeated after an episode of rejection at age 25. Hematologic findings returned to normal, but chronic graft-versus-host disease persisted. Esophageal cancer developed at age 35. Invasion of the bronchus and aorta by the tumor was suspected on computed tomography. Chemoradiotherapy was administered to down-stage the tumor, using low-dose cisplatin and 5-fluorouracil. After two courses of chemotherapy with cisplatin (total dose, 100 mg) and 5-fluorouracil (5000 mg) plus radiotherapy (30 Gy), Grade 3 diarrhea and bone marrow suppression developed, and treatment was discontinued. After resolution of toxicity, a good response to the neoadjuvant therapy was seen on computed tomography scan, and a subtotal esophagectomy was performed which demonstrated a complete response in the resected specimen. However, tongue cancer developed at age 40 years, and hemiglossectomy was performed. Patients with Fanconi anemia have a high risk of developing esophageal cancer while they are still young. Reduced doses of alkylating agents and radiotherapy are used in patients with Fanconi anemia. However, the optimal dosage of chemoradiotherapy and the treatment strategy for esophageal cancer in patients with Fanconi anemia remain unclear, and outcomes are generally extremely poor. In this patient, esophageal cancer associated with Fanconi anemia responded well to multidisciplinary therapy.

High‐dose cyclophosphamide treatment for refractory severe aplastic anemia in children

To determine if high-dose cyclophosphamide is an effective therapy for children with refractory severe aplastic anemia (SAA). SAA is an illness characterized by the depletion of hematopoietic precursors associated with life-threatening complications. Hematopoietic stem cell transplant (HSCT) is the treatment of choice if a human leukocyte antigen (HLA)-related donor is available. Immunosuppression with anti-thymocyte globulin (ATG) and cyclosporine A (CSA) is an option for patients who are not HSCT candidates. Unrelated donor HSCT has been used with limited success. High-dose cyclophosphamide has been used successfully in the treatment of adults with SAA, but experience in children is limited. Five pediatric patients who had failed previous immunosuppressive therapy for SAA were treated with high-dose cyclophosphamide (45 mg/kg/day x 4 days). After 12 months of treatment, two of five patients experienced a complete response with high-dose cyclophosphamide therapy. The two complete responders achieved red cell recovery with a hematocrit of >36% at days 212 and 112 and platelet recovery with a platelet count of >100 x 10(9)/L at days 126 and 324. Of the remaining patients, one patient failed to respond, and two patients expired from infectious complications. High-dose cyclophosphamide can lead to complete responses in children with SAA who have failed to respond to traditional immunosuppressive therapy.

Natural history of transfusion-independent non-severe aplastic anemia in children

Although the known clinical courses of non-severe aplastic anemia (NSAA) in children comprise spontaneous resolution, persistent NSAA, or progression to severe aplastic anemia (SAA), only a few published reports have indicated the outcome of transfusion-independent NSAA. We retrospectively evaluated the incidence and time of progression from transfusion-independent to transfusion-dependent NSAA or SAA. We reviewed the records of 70 children with acquired AA who were referred to our hospital between 1986 and 2006, and among them we found 22 patients who had transfusion-independent NSAA at diagnosis and were treated with supportive care alone until progression to transfusion-dependent AA. 22 patients were followed up for a median of 86 months (range, 11-198 months). The Kaplan-Meier estimates for progression-free survival were 62 +/- 12 and 22 +/- 13% at 60 and 120 months after diagnosis, respectively. None of the patients treated with supportive care alone improved hematologically. In conclusion, because the incidence of disease progression was high in patients with NSAA, a prospective randomized trial of early intervention with IST or observation alone until disease progression to SAA, followed by IST when the patients become transfusion-dependent is warranted.

Tacrolimus as an alternative to cyclosporine in the maintenance phase of immunosuppressive therapy for severe aplastic anemia in children

Given the paucity of data on the use of agents other than cyclosporine (CsA) in the maintenance phase of immunosuppressive therapy (IST) for severe aplastic anemia (SAA) in children, we sought to describe our experience with tacrolimus in pediatric SAA, and to compare outcomes with a preceding series of patients who received CsA. Eight patients with SAA diagnosed between 2003 and 2008 for whom no human leukocyte antigen (HLA)-matched sibling donor was identified underwent tacrolimus-based IST. These children were compared with a previously described series of 13 patients who had undergone CsA-based IST at our institution between 1990 and 2003. All patients initially received equine antithymocyte globulin (ATG) and corticosteroids. Complete response (CR) rate was 88% for tacrolimus and 85% for CsA. Median time to CR was approximately 7 months in both groups. Median follow-up duration was 2.4 years for tacrolimus and 8.4 years for CsA. Among responders with de novo SAA, relapse rate was 25% (n = 1) at 2 years for tacrolimus and 0% at 2 years and 23% (n = 3) at 5 years for CsA; no significant difference in relapse-free survival was detected between the two groups (P = 0.07). Paroxysmal nocturnal hemoglobinuria was seen in one patient on tacrolimus who had relapsed after CsA-based IST. Tacrolimus-based IST was well-tolerated. These data provide evidence that tacrolimus may be a suitable alternative to CsA as part of an IST regimen for SAA in children who lack an HLA-matched sibling and may have a more favorable profile of side effects than CsA.

Recent progress in the diagnosis and treatment of aplastic anemia in children

Recent progress in the diagnosis and treatment of aplastic anemia in children

Immunosuppressive activity of mesenchymal stem cells is not decreased in children with aplastic anemia

Aplastic anemia (AA) is characterized by a reduced number of hematopoietic stem cells (HSCs), resulting in peripheral pancytopenia. Several pathogeneses for AA have been hypothesized, and among these, the autoimmune-associated hypothesis is considered to be the most likely [1, 2]. Mesenchymal stem cells (MSCs) have been shown to exert immunosuppressive capacity both in vitro and in vivo. Normal bone marrow (BM)-derived MSCs suppress T cell function and may provide an immunoprotected environment for HSCs [3, 4]. Bacigalupo et al. [5] reported that MSCs derived from the BM of adult AA patients are defective in their ability to suppress T cell proliferation and cytokine release. They hypothesized that these defects may result in increased activation/proliferation of BM T cells, which suppress HSCs in AA patients. The aim of the present study was to investigate whether MSCs from pediatric AA patients also exert decreased suppressive activity on T cells when compared with those derived from normal individuals. Bone marrow samples from 34 AA children (16 males, 18 females) and 15 healthy volunteers were obtained following informed consent from either patients or parents. Median patient age was 10 years (range 2–21 years). The timing of sampling was at diagnosis in 15 patients and after immunosuppressive therapy (IST) with anti-thymocyte globulin and cycrosporin A in 19 patients. Eleven of these were IST responders and eight were non-responders. Aplasia was secondary to acute hepatitis in four patients and the cause was unknown in 30 patients. Seven patients had very severe AA, 19 patients had severe AA and eight patients had moderate AA. Bone marrow mononuclear cells (MNCs) were isolated and cultured as reported previously [5]. Briefly, MNCs were plated in a 25-cm tissue culture flask with complete MesenCult Basal Medium (Stem cell technologies, Vancouver, Canada) containing human MSC supplements. Adherent cells were expanded to the third generation. Characterization of MSCs was determined by flow cytometry and their differentiation into adipogenic and osteoblastic lineages. Surface markers of the MSCs were CD29?, CD44?, CD90?, CD105?, CD73?, CD34-, CD45and CD14-. To demonstrate capacity of MSCs to differentiate to adipocytes, cells were further cultured at 2 9 10 cells/flask with MesenCult basal medium supplemented with human adipocytogenic supplements (Stem cell technologies). Adipogenic differentiation was confirmed by the presence of lipid droplets under optical microscopy after 3 weeks. Similarly, for differentiation to osteoblasts, MSCs were cultured with MesenCult basal medium supplemented with an osteogenic differentiation kit (Stem cell technologies) containing dexamethasone (0.1 lmol/l), ascorbic acid (0.05 mmol/l) and glycerophosphate (10 mmol/l). After 5 weeks of culture, cell layers were stained with silver nitrate (Von Kossa method) in order to detect calcium deposition, which indicates osteogenesis. There were no differences in the expression of MSC surface markers and the differentiation capacity between AA patients and normal individuals. Immunosuppressive activity of MSCs from pediatric patients with AA was tested by their inhibitory effects on PHA-induced T cell proliferation. Peripheral blood MNCs from normal adult volunteers (2 9 10) were dispensed Y. Xu Y. Takahashi A. Yoshimi M. Tanaka H. Yagasaki S. Kojima (&) Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan e-mail: kojimas@med.nagoya-u.ac.jp

TINF2 mutations in children with severe aplastic anemia

To the Editor: Dyskeratosis congenita (DC), a bone marrow failure (BMF) syndrome associated with skin abnormalities, dystrophic nails, and leukoplakia, has been linked to mutations in genes that encode components of telomerase (dyskerin, TERC, TERT, NHP2, and NOP10). Recently, one of the components of the shelterin complex, TIN2, which is encoded by the TINF2 gene, was found to be mutated in some patients with autosomal dominant DC and in sporadic cases of DC [1,2]. Autosomal dominant forms of DC caused by mutations in TERT or TERC are often mild; many of these patients present with only BMF and are indistinguishable from individuals with idiopathic severe aplastic anemia (SAA) or myelodysplastic syndrome (MDS). In a recent issue of the journal, Pigullo et al. [3] hypothesized that mutations in NOLA1 (also known as GAR1), which encodes another component of the telomerase complex, might account for some cases of aplastic anemia (AA) in children. Of 108 patients with AA screened, none had a pathogenic mutation [3]. We postulated that TINF2 mutations might underlie some cases of idiopathic AA in childhood. To address this, we analyzed DNA samples from an anonymous registry [4] of pediatric patients who underwent unrelated donor hematopoietic stem cell transplantation (UD-HSCT) for SAA (n = 109) or MDS (n =137). We focused our mutational analysis on exon 6 of the gene, the site of all known TINF2 mutations linked to DC [1,2]. We identified potentially pathogenic mutations in 6 of 109 patients with SAA. A 2-year-old Caucasian male and a 10-year-old Caucasian male were heterozygous for TINF2 G845A (R282H), a mutation previously shown to cause DC with early onset AA [1,2]. A 6-year-old Caucasian female and a 17-year-old Caucasian male were heterozygous for C844T (R282C), another missense mutation linked to DC [2]. A 7-year-old Hispanic boy was heterozygous for a single nucleotide insertion that alters the TIN2 sequence beginning at residue 290 and introduces a stop codon (F290R291N292 → P290L291X). The remaining patient, a 4-year-old Hispanic girl, was heterozygous for the missense mutation T862C (F288L). The phenylalanine residue at position 288 of human TIN2 is conserved in chimpanzee, rat, and dog, whereas mouse and cow have a leucine residue at this position [1]. Therefore, it is unclear whether the F288L substitution is deleterious. No TINF2 mutations were detected in patients with MDS (P <0.01). Previously, 298 healthy control individuals of diverse ethnicities were screened for TINF2 mutations [1]; none had a TIN2 sequence change near amino acid 282 (P <0.001). We conclude that a significant proportion of patients who underwent UD-HSCT for SAA harbored mutations in TINF2 and may have had occult DC. Among pediatric patients with SAA in the registry, TINF2 mutations were more common than TERC mutations (5.5% vs. 0%, P <0.01) [4]. In pedigrees with DC due to mutation of TERC, signs and symptoms of the disease usually present in adulthood. Our findings, coupled with those of other investigators [1,2], suggest that mutation of TINF2 is more likely to manifest during childhood as SAA. In contrast, TERC and TERT gene mutations are associated with MDS and possibly acute myelogenous leukemia later in life.

Predicting Response to Immunosuppressive Therapy in Childhood Aplastic Anemia.

Aplastic anemia (AA) is defined as a pancytopenia caused by bone marrow failure; its pathogenesis is thought to involve autoimmune processes. Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporine (CyA) provides response rates of 50–70% for children with AA, but predictive markers of response to therapy have not been well defined. We previously investigated the clinical relevance of HLA, a minor population of paroxysmal nocturnal hemoglobinuria-type cells, and a specific auto-antibody associated with AA in pediatric patients and reported that there was no correlation between these markers and response to therapy (Yoshida N, et al. Br J Haematol, 2008). In the current study, we prospectively evaluated whether clinical and laboratory findings before treatment, including age, sex, interval between diagnosis and treatment, etiology, severity of disease, white blood cell (WBC) count, neutrophil count, hemoglobin level, reticulocyte count, and platelet count, could predict the IST response at 6 months. Subjects included a large population of pediatric AA patients enrolled in a multicenter AA-97 study conducted by the Japan Childhood Aplastic Anemia Study Group. Between October 1997 and September 2006, 312 children (186 boys and 126 girls) younger than 18 years who were newly diagnosed with AA were enrolled in the study and treated with a combination of ATG and CyA. The median age at diagnosis was 8 years (range, 1–17 years). Of the 312 patients, 261 had idiopathic AA, 44 had hepatitis-associated AA, and 7 had AA from other causes. In terms of severity, 156 patients had very severe disease, 107 had severe disease, and 49 had moderate disease. The median interval between diagnosis and treatment was 15 days (range, 1–180 days). The overall response rate was 56%. In multivariate analyses, lower WBC count, shorter interval between diagnosis and therapy, and male sex were predictive markers of better response. Patients with WBC <2500/μl had a significantly higher response rate than those with WBC ≥2500/μl (61 vs. 48%; P=0.008); this was the strongest predictor of response. Notably, response rate was inversely related to the interval between diagnosis and treatment; response rates of patients with an interval between diagnosis and treatment of <30 and ≥30 days were 60% and 43%, respectively (P=0.02). Boys had a better response compared with girls (62 vs. 48%; P=0.02). In conclusion, pretreatment clinical and laboratory findings influence the response rate to IST. Response is well correlated with WBC count rather than neutrophil count or severity of disease. IST should be started as soon as possible after diagnosis of AA, given that the response rate worsens as the interval between diagnosis and treatment increases.

Relapse of Children with Aplastic Anemia after Immunosuppressive Therapy

Although the therapeutic outcome for acquired aplastic anemia (AA) has improved markedly with the introduction of immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporine A (CyA), a significant portion of patients treated with IST subsequently relapse and require second-line therapy. However, detailed analysis of the relapse cases has not been reported. In this study, we assessed the relapse rate, response to second-line treatment after relapse and prognosis. From November 1992 to July 2007, 473 newly diagnosed AA children (213 female, 260 male) entered two consecutive prospective studies (AA-92 and AA-97). The median age was 8 years, ranging from 1 to 18 years. Patients with very severe (n = 210), severe (n = 149) and non-severe disease (n = 114) received initial IST consisting of ATG and/or CyA. At six months after the initial IST, 280 patients (59.2%) achieved CR (n = 94) or PR (n=186). Relapse is defined by conversion to no response (NR) from partial or complete response (PR/CR). Among the 280 patients who responded to IST, 49 (17.5%) relapsed. The cumulative incidence of relapse was 19.6% at 10 years and the median time to relapse was 18 months, ranging 7 to 138 months. Among the 49 patients who relapsed, 22 received a second round of IST with ATG and CyA. Fourteen patients (63.6%) responded to the second round. However, three relapsed, and two developed paroxysmal nocturnal hemoglobinuria. Eight patients received CyA after relapse. Four patients responded to CyA, but two relapsed subsequently. Hematopoietic stem cell transplantation (HSCT) was attempted in 26 patients who relapsed after initial responses. Before HSCT, nine received a second course of IST with ATG and CyA and two received CyA. Fifteen patients progressed directly to HSCT. Bone marrow transplantation (BMT) from an HLA-matched sibling (n =7), HLA-matched family member (n = 1), or HLA-mismatched family member (n = 2) was performed in 10 patients, and all are presently alive. BMT from an unrelated donor was attempted in 13 patients, and four died of complications related to BMT. Cord blood transplantation from an unrelated donor was attempted in two patients and two patients are alive. Of the 26 patients who received HSCT, 21 are alive and well, 22 to 137 months (median 72 months) following transplantation. There were seven deaths out of total 49 who initially relapsed. The causes of death were HSCT-related complications (n = 5), MDS/acute myelogenous leukemia (n = 1), bacteremia (n = 1). Eight of 9 patients who received HSCT following a second round of IST are alive and well. The present study suggests that a second round of IST should be offered to the patients who relapse, and HSCT should be considered for the patients who fail to respond to the second round of IST.

Aplasia medular grave adquirida: evolución histórica de los resultados obtenidos con trasplante de progenitores hematopoyéticos de donante familiar. Estudio del Grupo Español para el Trasplante de Médula Ósea en Niños (GETMON)

Allogeneic haematopoietic stem-cell transplantation is the treatment of choice for acquired aplastic anaemia in children. Experience with this approach from Spanish Working Party for Bone Marrow Transplantation in Children in two sequential time periods (1982-1990 and 1991-2004) is reported. Sixty two consecutive patients with a median age of 10 years were transplanted; 18 in the 1982-1990 period and 44 in the 1991-2004 period. Conditioning regimen consisted mainly of irradiation and cyclophosphamide in the first period (72 % of patients) and cyclophosphamide +/- anti-thymocyte globulin (62 %) in the second. Graft versus host disease prophylaxis consisted of cyclosporine in most patients (57/62). Fifty one patients are alive and disease-free at a median follow-up of 127 months. Five years probability of event-free survival is 82 %. The survival increased from 61 % to 91 % during the two time periods. Eleven patients died from graft failure or rejection (3), acute or chronic graft versus host disease and infection (4) or multi-organ failure (4). Univariate analysis identified two significant prognostic factors: interval diagnostic/transplant and time period of transplant (for both p = 0.03). This experience corroborates that allogeneic haematopoietic stem-cell transplantation is the best treatment for severe acquired aplastic anaemia, with a current disease-free survival of 90 % of patients.