Enhanced human hematopoietic stem and progenitor cell engraftment by blocking donor T cell-mediated TNFα signaling.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative therapy, but the large number of HSCs required limits its widespread use. Host conditioning and donor cell composition are known to affect HSCT outcomes. However, the specific role that the posttransplantation signaling environment plays in donor HSC fate is poorly understood. To mimic clinical HSCT, we injected human umbilical cord blood (UCB) cells at different doses and compositions into immunodeficient NOD/SCID/IL-2Rgc-null (NSG) mice. Surprisingly, higher UCB cell doses inversely correlated with stem and progenitor cell engraftment. This observation was attributable to increased donor cell-derived inflammatory signals. Donor T cell-derived tumor necrosis factor-α (TNFα) was specifically found to directly impair the survival and division of transplanted HSCs and progenitor cells. Neutralizing donor T cell-derived TNFα in vivo increased short-term stem and progenitor cell engraftment, accelerated hematopoietic recovery, and altered donor immune cell compositions. This direct effect of TNFα on transplanted cells could be decoupled from the indirect effect of alleviating graft-versus-host disease (GVHD) by interleukin-6 (IL-6) blockade. Our study demonstrates that donor immune cell-derived inflammatory signals directly influence HSC fate, and provides new clinically relevant strategies to improve engraftment efficiency during HSCT.

Phase 1b study of galunisertib in combination with gemcitabine in Japanese patients with metastatic or locally advanced pancreatic cancer.

PURPOSE: Transforming growth factor-beta inhibitors may enhance the antitumor activity of gemcitabine with acceptable safety and tolerability. This open-label, multicenter, non-randomized phase 1b study assessed the safety/tolerability, pharmacokinetics, and tumor response of galunisertib plus gemcitabine in Japanese patients with advanced or metastatic pancreatic cancer. METHODS: During each 28-day cycle, galunisertib 150 mg was administered orally twice daily (300 mg/day) for 14 days, followed by 14 days of rest. Gemcitabine 1000 mg/m2 was intravenously given on Days 8, 15, and 22. Safety was assessed by the incidence of dose-limiting toxicities (DLTs) in the first cycle and treatment-emergent adverse events (TEAEs). Efficacy was assessed by antitumor activity and changes in carbohydrate antigen 19-9 (CA19-9). RESULTS: No DLTs were reported. All 7 enrolled patients had ≥1 TEAE, of which the most common included anorexia, decreased neutrophil count, and decreased white blood cell count. Grade ≥3 TEAEs were observed in 6 patients; 4 patients had Grade ≥3 TEAEs (decreased neutrophil, white blood cell, and lymphocyte count; hypophosphatemia) considered possibly related to study drug(s). The pharmacokinetic profile of galunisertib in combination with gemcitabine was similar to that previously observed for galunisertib alone. The clinical response [complete response (CR), partial response (PR), or stable disease] rate was 42.9%, and the median progression-free survival was 64 days; no CR/PR were achieved. CONCLUSION: Galunisertib plus gemcitabine had an acceptable safety/tolerability profile with evidence of efficacy in Japanese patients with advanced or metastatic pancreatic cancer.

Humanized Chronic Graft-versus-Host Disease in NOD-SCID il2rγ-/- (NSG) Mice with G-CSF-Mobilized Peripheral Blood Mononuclear Cells following Cyclophosphamide and Total Body Irradiation.

Chronic graft-versus-host disease (cGvHD) is the major source of late phase morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Humanized acute GvHD (aGvHD) in vivo models using NOD-SCID il2rγ-/- (NSG) mice are well described and are important tools for investigating pathogenicity of human cells in vivo. However, there have been only few reported humanized cGvHD mouse models. We evaluated if prolonged inflammation driven by low dose G-CSF-mobilized human PBMCs (G-hPBMCs) would lead to cGvHD following cyclophosphamide (CTX) administration and total body irradiation (TBI) in NSG mice. Engraftment was assessed in peripheral blood (PB) and in specific target organs by either flow cytometry or immunohistochemistry (IHC). Tissue samples were harvested 56 days post transplantation and were evaluated by a pathologist. Some mice were kept for up to 84 days to evaluate the degree of fibrosis. Mice that received CTX at 20mg/kg did not show aGvHD with stable expansion of human CD45+ CD3+ T-cells in PB (mean; 5.8 to 23.2%). The pathology and fibrosis scores in the lung and the liver were significantly increased with aggregation of T-cells and hCD68+ macrophages. There was a correlation between liver pathology score and the percentage of hCD68+ cells, suggesting the role of macrophage in fibrogenesis in NSG mice. In order to study long-term survival, 6/9 mice who survived more than 56 days showed increased fibrosis in the lung and liver at the endpoint, which suggests the infiltrating hCD68+ macrophages may be pathogenic. It was shown that the combination of CTX and TBI with a low number of G-hPBMCs (1x106) leads to chronic lung and liver inflammation driven by a high infiltration of human macrophage and mature human T cells from the graft, resulting in fibrosis of lung and liver in NSG mice. In conclusion this model may serve as an important pre-clinical model to further current understanding of the roles of human macrophages in cGvHD.

Significant Transplantation-Related Mortality from Respiratory Virus Infections within the First One Hundred Days in Children after Hematopoietic Stem Cell Transplantation.

Respiratory viral infections (RVI) are important in hematopoietic stem cell transplantations (HSCT) and knowledge regarding incidence, morbidity, mortality, and long-term pulmonary complications is limited. We report a study to evaluate incidence and outcomes, both short and long-term, of RVI in children receiving HSCT. Between January 2000 and December 2012, 844 patients underwent hematopoietic stem cell transplantation (HSCT) at the Hospital for Sick Children: 491 were allogeneic and 353 were autologous. When screening for causes of death in the first year after HSCT in the 844 patients, we found that RVI as a cause of death was only evident in the first 100 days after HSCT. Fifty-four (6.5%) patients were found to have an RVI within the first 100 days after HSCT (allogeneic = 32, autologous = 22). Upper and lower respiratory tract infections were documented in 31 (57%) and 23 (43%) patients, respectively. Viruses were parainfluenza (35%), respiratory syncytial virus (28%), influenza (22%), adenovirus (7%), human metapneumovirus (4%), coronavirus (2%), and rhinovirus (2%). Three patients relapsed with their primary disease before day 100 and were excluded. The overall mortality for the remaining 51 patients was 10% (allogeneic = 4, autologous = 1). All 5 deaths were directly attributable to RVI and all 5 deaths occurred in patients with a lower respiratory tract infection. The remaining patients were followed for a median of 4.3 years (range, 1.4 to 11.8) and no chronic pulmonary complications were observed. A clear seasonal pattern for contracting RVI was evident with 65% of total RVI occurring between October and March (35 of 427 versus 19 of 417, P = .03). Given the significant mortality from RVI and the challenges in preventing them, choosing the time to start HSCT, whenever possible, may help prevent RVI and improve outcomes.

Relative bioequivalence of amoxicillin dissolved in breast milk.

BACKGROUND: Oral antibiotics use in infants in developing countries is challenging because liquid formulations are often unavailable. However, dissolving solid formulation of drugs in water poses a risk of gastrointestinal infection. Although mother's milk may be a potential vehicle, no evidence exists to indicate that antibiotics dissolved in human milk are bioequivalent to those dissolved in water. Therefore, we compared pharmacokinetic parameters of an orally administered antibiotic, amoxicillin, dissolved in human milk, to those of water-dissolved amoxicillin. METHODS: A pharmacokinetic study was conducted in 16 healthy adult volunteers in a randomised crossover design. Marketed amoxicillin powder for suspension was dissolved in either human milk or water at a final concentration of 50 mg/mL, and 10 mL was given orally in a fasting state. Timed blood samples were obtained and plasma amoxicillin was quantified using liquid chromatography-mass spectrometry. FINDINGS: Results showed that pharmacokinetic parameters, including area-under-the-curve, Cmax and half-life of the water-based and milk-based amoxicillin administration were not significantly different. 90% CIs of the ratios of these parameters in concomitant breast milk administration to those of water were within 89% and 116%, suggesting they are bioequivalent (defined as a range between 80% and 125%). INTERPRETATION: We conclude that oral administration of amoxicillin dissolved in human milk at 50 mg/mL results in pharmacokinetics profiles comparable to amoxicillin dissolved in water. Pharmaceutical interactions between amoxicillin and breast milk are unlikely, suggesting no need to modify dosing schedules.

Influence of pre-hydration and pharmacogenetics on plasma methotrexate concentration and renal dysfunction following high-dose methotrexate therapy.

High-dose methotrexate therapy (HD-MTX) has been well established for the treatment of childhood acute lymphoblastic leukemia (ALL). The aims of this study were to investigate whether clinical and pharmacogenetic factors influence plasma MTX concentration and renal dysfunction in patients treated with HD-MTX. In a total of 127 courses of HD-MTX in 51 patients with childhood ALL, influence of clinical and pharmacogenetic factors on plasma MTX concentration and HD-MTX-related renal dysfunction was evaluated. Clinical factors included age, gender, duration of HD-MTX continuous-infusion and duration of pre-hydration before HD-MTX. Pharmacogenetic factors included 5 gene polymorphisms within the MTX pathway genes, namely, SLC19A1, MTHFR, ABCC2 and ABCG2. Short duration of pre-hydration before HD-MTX is the most important risk factor for prolonged high MTX concentration (p < 0.001, OR 6.40, 95 % CI 2.39-17.16) and renal dysfunction (p = 0.013, OR 3.15, 95 % CI 1.27-7.80). The T allele at MTHFR C677T was the risk factor for prolonged high MTX concentration (p = 0.009, OR 5.54, 95 % CI 1.54-19.85), but not for renal dysfunction. We found the influence of MTHFR C677T polymorphism on prolonged high MTX concentration. We reconfirmed the importance of adequate pre-hydration before HD-MTX to prevent prolonged high MTX concentration and MTX-related renal dysfunction.

Flow cytometric chemosensitivity assay using JC­1, a sensor of mitochondrial transmembrane potential, in acute leukemia.

PURPOSE: The purpose of the study is to establish a simple and relatively inexpensive flow cytometric chemosensitivity assay (FCCA) for leukemia to distinguish leukemic blasts from normal leukocytes in clinical samples. METHODS: We first examined whether the FCCA with the mitochondrial membrane depolarization sensor, 5, 50, 6, 60-tetrachloro-1, 10, 3, 30 tetraethyl benzimidazolo carbocyanine iodide (JC-1), could detect drug-induced apoptosis as the conventional FCCA by annexin V/7-AAD detection did and whether it was applicable in the clinical samples. Second, we compared the results of the FCCA for prednisolone (PSL) with clinical PSL response in 18 acute lymphoblastic leukemia (ALL) patients to evaluate the reliability of the JC-1 FCCA. Finally, we performed the JC-1 FCCA for bortezomib (Bor) in 25 ALL or 11 acute myeloid leukemia (AML) samples as the example of the clinical application of the FCCA. RESULTS: In ALL cells, the results of the JC-1 FCCA for nine anticancer drugs were well correlated with those of the conventional FCCA using anti-annexin V antibody (P < 0.001). In the clinical samples from 18 children with ALL, the results of the JC-1 FCCA for PSL were significantly correlated with the clinical PSL response (P = 0.005). In ALL samples, the sensitivity for Bor was found to be significantly correlated with the sensitivity for PSL (P = 0.005). In AML samples, the Bor sensitivity was strongly correlated with the cytarabine sensitivity (P = 0.0003). CONCLUSIONS: This study showed the reliability of a relatively simple and the FCCA using JC-1, and the possibility for the further clinical application.

Pregnancy outcomes following gabapentin use: results of a prospective comparative cohort study.

OBJECTIVES: Our objectives were to 1) determine whether first-trimester use of gabapentin is associated with an increased risk for major malformations; 2) examine rates of spontaneous abortions, therapeutic abortions, stillbirths, mean birth weight and gestational age at delivery; and 3) examine rates of poor neonatal adaptation syndrome following late pregnancy exposure. METHODS: The study design was prospective. Women were included who initially contacted the services between 5 and 8 weeks with a comparison group of women exposed to nonteratogens, collected in a similar manner. RESULTS: We have data on 223 pregnancy outcomes exposed to gabapentin and 223 unexposed pregnancies. The rates of major malformations were similar in both groups (p = 0.845). There was a higher rate of preterm births (p = 0.019) and low birth weight <2,500 g (p = 0.033) in the gabapentin group. Among infants who were exposed to gabapentin up until delivery, 23 of 61 (38%) were admitted to either the neonatal intensive care unit or special care nursery for observation and/or treatment, vs 6 of 201 (2.9%) live births in the comparison group (p < 0.001). There were 2 cases of possible poor neonatal adaptation syndrome in neonates exposed to gabapentin close to delivery, compared with none in the comparison group, although it must be noted that these infants were concomitantly exposed to other psychotropic drugs. Among the women who took gabapentin, the major indications were pain (n = 90; 43%) and epilepsy (n = 71; 34%); the remainder were for other indications, mostly psychiatric. CONCLUSION: Our results suggest that although this sample size is not large enough to make any definitive conclusions, and there was no comparator group treated with other antiepileptic drugs, gabapentin use in pregnancy does not appear to increase the risk for major malformations. This finding and the increased risk for low birth weight and preterm birth require further investigation.

Inhibition of cathepsin S reduces allogeneic T cell priming but not graft-versus-host disease against minor histocompatibility antigens.

Cathepsin (Cathepsin) S, L, and B proteases mediate antigen presentation on major histocompatibility complex (MHC) class II by degrading the invariant chain Ii, which blocks peptide loading. The ability of the Cathepsin S inhibitor LHVS (morpholinurea-leucine-homophenylalanine-vinylsulfone phenyl) to impede antigen presentation has led its development as a therapy for autoimmune diseases. There is substantial evidence that donor T cell recognition of host minor histocompatibility antigens (miHA) and subsequent destruction of host tissue mediates graft-versus-host disease (GVHD). We hypothesized that enzymes involved in antigen presentation may play a role in the development of GVHD. Using the C57BL/6 → BALB.B minor mismatch acute GVHD (aGVHD) model, we found that the cathepsin S activity of spleens from allogenetically transplanted mice were significantly increased 1 week after transplantation compared with syngeneic mice. Although LHVS decreased T cell priming responses against both single OVA antigen and miHA in vitro, LHVS did not reduce the severity of aGVHD. In fact, LHVS exacerbated a CD4(+)-T cell-dependent model of GVHD similar to chronic GVHD. This suggests that cytokines rather than T cells may mediate much of the damage in the aGVHD model and that therapeutics based on inhibition of antigen presentation for GVHD must be approached with caution.

Influence of CYP3A5 and ABCB1 gene polymorphisms on calcineurin inhibitor-related neurotoxicity after hematopoietic stem cell transplantation.

BACKGROUND: One severe side effect of calcineurin inhibitors (CNIs: such as cyclosporine [CsA] and tacrolimus [FK506]) is neurotoxicity. CNIs are substrates for CYP3A5 and P-glycoprotein (P-gp), encoded by ABCB1 gene. In the present study, we hypothesized that genetic variability in CYP3A5 and ABCB1 genes may be associated with CNI-related neurotoxicity. METHODS: The effects of the polymorphisms, such as CYP3A5 A6986G, ABCB1 C1236T, G2677T/A, and C3435T, associated with CNI-related neurotoxicity were evaluated in 63 patients with hematopoietic stem cell transplantation. RESULTS: Of the 63 cases, 15 cases developed CNI-related neurotoxicity. In the CsA patient group (n = 30), age (p = 0.008), hypertension (p = 0.017), renal dysfunction (p < 0.001), ABCB1 C1236T (p < 0.001), and G2677T/A (p = 0.014) were associated with neurotoxicities. The CC genotype at ABCB1 C1236T was associated with it, but not significantly so (p = 0.07), adjusted for age, hypertension, and renal dysfunction. In the FK506 patient group (n = 33), CYP3A5 A6986G (p < 0.001), and ABCB1 C1236T (p = 0.002) were associated with neurotoxicity. At least one A allele at CYP3A5 A6986G (expressor genotype) was strongly associated with it according to logistic regression analysis (p = 0.01; OR, 8.5; 95% CI, 1.4-51.4). CONCLUSION: The polymorphisms in CYP3A5 and ABCB1 genes were associated with CNI-related neurotoxicity. This outcome is probably because of CYP3A5 or P-gp functions or metabolites of CNIs.

Chemo-sensitivity in a panel of B-cell precursor acute lymphoblastic leukemia cell lines, YCUB series, derived from children.

Sensitivity to 10 anticancer drugs was evaluated in 6 childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cell lines. Authenticity of newly established cell lines was confirmed by genomic fingerprinting. The line YCUB-5R established at relapse was more resistant to 4-hydroperoxy-cyclophosphamide, cytarabine, L-asparaginase, topotecan, fludarabine, and etoposide than YCUB-5 from the same patient at diagnosis. Of the drugs tested, etoposide and SN-38 (irinotecan) showed highest efficacy in the panel, with 50% growth inhibition at 0.22-1.8 microg/ml and 0.57-3.6 ng/ml, respectively. This cell line panel offers an in vitro model for the development of new therapies for childhood BCP-ALL.

[Cutaneous non-tuberculous mycobacterial infection following cord blood stem cell transplantation].

We describe a 4-year-old-girl with familial hemophagocytic lymphohistiocytosis (FHL) who developed disseminated cutaneous nontuberculous mycobacterial (NTM) infection after unrelated cord blood stem cell transplantation (uCBSCT). After transplantation, the patient developed steroid-refractory acute graft-versus-host disease, and was given methylprednisolone, cyclosporin and mycophenolate mofetil. Six months after uCBSCT, cutaneous lesions that looked like insect bites appeared and spread widely over the thighs. NTM infection was diagnosed by skin biopsy although no organism could be identified. Minocycline (MINO) and sulfamethoxazole/trimethoprim (ST) were administered. However, the cutaneous disease followed a course of remissions and exacerbations. One month after the skin biopsy, mycobacterium chelonae was detected by bacteriological culture of abscess drainage. Ten months after uCBSCT, the cutaneous lesions quickly progressed and the inguinal lymph nodes became enlarged and painful. Then the antibiotics were switched from MINO and ST to amikacin and clarithromycin (CAM) based on the results of mycobacterial susceptibility test. The cutaneous lesions gradually improved after continuous administration of CAM. Cutaneous NTM infection is rare, but it may occur in immunocompromised patients after SCT.

Biomarkers in newly diagnosed pediatric-extensive chronic graft-versus-host disease: a report from the Children's Oncology Group.

Numerous chronic graft-versus-host disease (cGVHD) biomarkers have been identified in limited, single-institution studies without validation. We hypothesized that plasma-derived biomarkers could diagnose, classify, and evaluate response in children with cGVHD. We performed a concomitant analysis of a number of known and predicted peripheral blood cGVHD biomarkers from a Children's Oncology Group (COG) phase 3 cGVHD therapeutic trial. A total of 52 newly diagnosed patients with extensive cGVHD were compared for time of onset after blood and marrow transplantation (BMT) (early, 3-8 months; late, > or = 9 months) with 28 time-matched controls with no cGVHD (early, 6 months after BMT; late, 12 months after BMT). Soluble B-cell activation factor (sBAFF), anti-dsDNA antibody, soluble IL-2 receptor alpha (sIL-2Ralpha), and soluble CD13 (sCD13) were elevated in patients with early-onset cGVHD compared with controls. sBAFF and anti-dsDNA were elevated in patients with late-onset cGVHD. Some of the biomarkers correlated with specific organ involvement and with therapeutic response. These 4 biomarkers had high specificity with higher sensitivity in combination. Changes in biomarker concentrations with immune reconstitution after transplantation significantly affected interpretation of results. The identified biomarkers have the potential for improved classification, early response evaluation, and direction of cGVHD treatment, but require validation in larger studies. This study is registered at www.cancer.gov/clinicaltrials as no. COG-ASCT0031.

[Acute appendicitis during bone marrow suppression following chemotherapy for acute leukemia; report of three cases].

We report here on the clinical courses of three cases of acute appendicitis during a period of myelosuppression after chemotherapy for acute leukemia. The patients were two boys and one girl with a mean age 11 years (range, 10-12). Two of the patients had acute myeloid leukemia (AML) in subtypes M1 and M2, while the third had acute lymphoblostic leukemia of subtype L1 (FAB classification). All patients had clinical features of fever, abdominal pain, and elevations of C-reactive protein. However, the typical peritoneal signs were blunted and developed transiently in two cases. All patients were diagnosed as having appendicitis with abdominal computed tomography scan (CT), and proceeded to appendectomy. With perioperative support utilizing antibiotics, antifungal agents, blood components, and granulocyte-colony stimulating factor, surgical intervention was successfully performed, and all patients were able to undergo chemotherapy courses shortly after surgery. Histological examinations of the appendectomy specimens showed infiltration of most of the lymphoid cells and a few neutrophils in the wall of the appendix. Enhanced CT was useful in diagnosing appendicitis, which needs to be considered in cases presenting with clinical symptoms such as described here. Because of a high mortality rate after appendix perforation, immediate surgical intervention with sufficient perioperative support should be performed.

In vivo control of acute lymphoblastic leukemia by immunostimulatory CpG oligonucleotides.

Despite considerable success in treating newly diagnosed childhood acute lymphoblastic leukemia (ALL), relapsed disease remains a significant clinical challenge. Using a NOD/SCID mouse xenograft model, we report that immunostimulatory DNA oligonucleotides containing CpG motifs (CpG ODNs) stimulate significant immune activity against primary human ALL cells in vivo. The administration of CpG ODNs induced a significant reduction in systemic leukemia burden, mediated continued disease control, and significantly improved survival of mice with established human ALL. The death of leukemia cells in vivo was independent of the ability of ALL cells to respond directly to CpG ODNs and correlated with the production of IL-12p70, IFN-alpha, and IFN-gamma by the host. In addition, depletion of natural killer cells by anti-asialo-GM1 treatment significantly reduced the in vivo antileukemic activity of CpG ODN. This antileukemia effect was not limited to the xenograft model because natural killer cell-dependent killing of ALL by human peripheral blood mononuclear cells (PBMCs) was also increased by CpG ODN stimulation. These results suggest that CpG ODNs have potential as therapeutic agents for the treatment of ALL.

[Recurrent spontaneous regression of aleukemic leukemia cutis in a girl with acute monocytic leukemia].

Aleukemic leukemia cutis is a rare form of leukemia manifestation, defined as a skin infiltration of leukemic cells with no evidence of leukemia in the bone marrow. A 4-month-old girl was referred to our hospital because of exanthema that appeared and regressed repeatedly. Histological examination revealed partial infiltration of histiocytic cells in the skin lesion. However, the diagnosis could not be made at that time. At 9 and at 13 months old, appearances of exanthema similar to the previous time were combined with systemic fever, abnormal coagulation tests, and the marked increases of atypical lymphocytes in peripheral blood: however, these symptoms resolved spontaneously. At 14 months old, deterioration of the exanthema and an increase in the peripheral leukocyte counts were observed. Bone marrow aspiration revealed the predominance of monocytic blasts (76.4%), and the patient was diagnosed as having acute monocytic leukemia (M5b) with leukemia cutis. Complete remission was obtained with standard chemotherapy. Six months after the therapy was completed, an extramedullary relapse occurred in the inguinal lymph nodes, which was successfully treated with allogeneic bone marrow transplantation from an HLA-matched unrelated donor, and the patient has been free of disease for two years after the transplantation.

[Reduced-intensity stem cell transplantation using allogeneic peripheral blood stem cells from the same donor for relapsed leukemia after bone marrow transplantation].

We report the clinical courses of two cases with relapsed acute lymphoblastic leukemia (ALL) after allogeneic bone marrow transplantation (BMT). After reinduction chemotherapy, the patients received reduced-intensity stem cell transplantation using allogeneic peripheral blood stem cells harvested from their previous BMT donors. The conditioning regimen used consisted of fludarabine and melphalan. Graft-versus-host disease (GVHD) prophylaxis was performed with low dose cyclosporin A (CsA, 1 mg/kg/day d.i.v.) on its own. The regimen related toxicity was minimal, and stable engraftment was achieved. Since acute GVHD had not developed by day 30, CsA was stopped abruptly in both cases. After CsA withdrawal, acute GVHD developed, and subsequent chronic GVHD. One of two cases is alive without any relapse of the leukemia 40 months after the peripheral blood stem cell transplantation (PBSCT). In the other case, ALL relapsed 15 months after the PBSCT, however, complete remission was again induced concomitantly with reactivated GVHD. In both these cases, the results suggest that using PBSC as a stem cell source and abrupt cessation of GVHD prophylaxis provided a potent graft-versus-leukemia effect.

Successful bone marrow transplantation for severe aplastic anemia in a patient with persistent human parvovirus B19 infection.

Persistent infection with human parvovirus B19 (B19) is primarily associated with chronic bone marrow failure in immunocompromised patients, but occasionally this organism may also affect immunocompetent hosts. B19 is also suggested as a causative agent of organ failure during bone marrow transplantation (BMT). We herein report the case of a 9-year-old girl with no previous history of immunodeficiency who developed severe aplastic anemia concurrent with B19 persistent infection. Both immunoglobulin (Ig)M antibody to B19 and B19 DNA identified by real-time polymerase chain reaction were found in the patient's serum at time of diagnosis of aplastic anemia. No giant proerythroblasts were found in her bone marrow at diagnosis. Although intravenous administration of Ig (IVIg) reduced serum B19 DNA, the aplastic status of her bone marrow did not improve. Both aplastic anemia and persistent B19 viremia were successfully treated by BMT from an HLA-identical sibling donor. Serum B19 DNA increased temporarily after BMT; however, neither organ nor marrow failure was observed. B19 DNA disappeared from the serum 2 months after BMT, suggesting that a normal immune response was restored by BMT and terminated the B19 viremia. During BMT, use of high-titer IVIg for B19 might prevent B19-associated organ failure.