The response of bovine beta‐lactoglobulin‐specific T‐cell clones to single amino acid substitution of T‐cell core epitope

Cow’s milk is one of the most common food allergens in the first year of life, with approximately 2.5% of infants experiencing an allergic reaction to it. Beta‐lactoglobulin (BLG) is one of the major allergens in cow’s milk. Previously, we reported that four of six T‐cell clones (TCC) which were established from cow’s milk allergy patients recognized BLGp97‐117 as the core sequence and also recognized BLG in association with the human leucocyte antigen (HLA)‐DRB1*0405 allele. Using two of these four TCCs, we evaluated the T‐cell response to BLG peptides with single amino acid substitution or deletion and identified BLGp102‐112 as the minimum essential region in BLGp97‐117. In the alanine‐scan assay, the proliferative responses of TCCs to pE108A disappeared, and the proliferative responses of TCCs to pC106A decreased. In the analog peptide proliferation assay, pY102S had retained some T‐cell response to the two TCCs. Collecting these results, we propose a motif for the interaction between the HLA‐DRB1*0405 allele and antigen peptide, and suggest that BLGp105‐108 are important residues to retain the TCR/BLG‐peptide/HLA complex. pY102A and pY102S are partial agonists for the T‐cell receptor. These peptides might be considered as candidate peptides for the modification of the T‐cell response to BLG in cow’s milk allergy.     

Haploidentical hematopoietic stem cell transplantation for paediatric high‐risk T‐cell acute lymphoblastic leukaemia

Paediatric HR T‐cell ALL demonstrates dismal prognosis with chemotherapy, and poor outcomes could be improved with allo‐SCT. HID‐SCT is an almost immediately available choice; however, few studies have focused on the outcomes of HID‐SCT for paediatric HR T‐ALL. Forty‐eight consecutive HR T‐ALL children who underwent HID‐SCT were included. Survival outcomes and factors predictive of outcomes were retrospectively analysed. Of the 48 patients, 35 were in CR1, 10 in CR2, and three in relapse. The cumulative incidence of grade 3/4 aGVHD was 10.4% and that of extensive cGVHD was 28.4%. The CIR at three yr was 30.8% and that of NRM at three yr was 14.7%. At a median follow‐up of 20.0 (range 2.5–124.2) months, the three‐yr LFS was 54.4%. Children who received transplants during CR1 had a better LFS (65.7% vs. 26.0%, p = 0.008) and a lower relapse rate (19.8% vs. 56.7%, p = 0.014) compared to those during non‐CR1. HID‐SCT is feasible for HR T‐ALL children, and survival outcomes are better when performed in CR1 compared to non‐CR1. Prospective clinical trials would be needed to confirm that.     

Successful cord blood transplantation using a reduced‐intensity conditioning regimen for advanced childhood‐onset cerebral adrenoleukodystrophy

Awaya T, Kato T, Niwa A, Hiramatsu H, Umeda K, Watanabe K‐i, Shibata M, Yamanaka Y, Maruya E, Saji H, Nakahata T, Adachi S. Successful cord blood transplantation using a reduced‐intensity conditioning regimen for advanced childhood‐onset cerebral adrenoleukodystrophy.
Pediatr Transplantation 2011: 15: E116–E120. © 2009 John Wiley & Sons A/S. Abstract: The CCALD, which is caused by a mutation of the ABCD1 gene that encodes a peroxisomal membrane protein, progresses to a stage where the patient is in a vegetative state and can cause death within 3–5 yr after the appearance of neurological symptoms. Although HSCT is the only means of preventing the progression of this disease, HSCT is currently recommended only for cases diagnosed in the early stages. Previous reports on HSCT in advanced CCALD have indicated that the complications of the HSCT procedure seem to outweigh its benefits with respect to survival and neurological outcome. In this case, we successfully treated advanced CCALD with CBT using a reduced‐intensity conditioning regimen to reduce regimen‐related toxicity and transplant‐associated morbidity and mortality. Neither neurological deterioration nor deterioration of MRI abnormalities were observed during the clinical course. We report that CBT using the reduced‐intensity conditioning regimen was well tolerated, stopped disease progression and contributed to a good neuropsychological outcome in this case of advanced CCALD.     

Haploidentical hematopoietic stem cell transplantation with post‐transplant high‐dose cyclophosphamide in high‐risk children: A single‐center study

Recently, haploidentical transplantations have been performed with unmanipulated BM or PBSC. This approach is becoming more widely adopted with the use of PTCY. However, there is limited evidence about this approach in children. We present 15 children who received 16 haploidentical HSCT with unmanipulated BM or PBSC using PTCY for GVHD prophylaxis. Post‐transplant CY(50 mg/kg IV) was given on the third and fifth day, and CsA or tacrolimus with MMF or MP was also used for GVHD prophylaxis. All patients engrafted at a median of 16 and 18 days for neutrophil and thrombocyte recovery, respectively. Grades II–III acute GVHD developed in seven patients, and mild chronic GVHD was found in two patients. Two patients died within the first 100 days due to sepsis (TRM 12.5%). Eleven patients are currently alive, with a median follow‐up of 12 months (range 6–22 months). The 12‐month OS and DFS were 75 ± 10.8% and 68.8 ± 11.6%, respectively. Our results with these high‐risk patients are encouraging for haploidentical HSCT in pediatric patients. Future studies should continue to assess haploidentical HSCT, including comparison of other modalities, in a primary pediatric population.     

Pre‐freeze and post‐thaw characteristics on chimerism patterns in double‐unit cord blood transplantation

We analyzed the pre‐freeze and post‐thaw characteristics on chimerism patterns in 20 cases of double‐unit cord blood transplantation. The cord blood units (CBUs) were a 4/6 HLA match or better with recipients and achieved a minimum combined precryopreservation cell dose of 3.7 × 10⁷ total nucleated cell (TNC)/kg. The unit with a higher cell dose was infused first. All evaluable patients engrafted at a median of 18 days. By day 42, neutrophil engraftment was derived from both donors in 63% of cases and a single donor in 37% of patients. By day 100, one unit predominated in 80% of the patients. Higher pre‐freeze TNC and CD34+ cell doses were associated with cord predominance in 67% of patients. Pediatr Blood Cancer 2009;52:547–550. © 2008 Wiley‐Liss, Inc.     

Comparison of outcomes after HLA‐matched unrelated and αβ T‐cell‐depleted haploidentical hematopoietic stem cell transplantation for children with high‐risk acute leukemia

T‐cell‐depleted HAPLO HSCT is an option to treat children with high‐risk acute leukemia lacking an HLA‐identical donor. We reviewed the outcome of children with acute leukemia after HAPLO (n = 21) and HLA‐MUD (n = 32) transplantation. The proportion of patients with ≥CR2 was significantly higher in HAPLO transplantation than MUD transplantation. Patients with MUD transplantation were significantly higher ABO incompatible than patients with HAPLO transplantation. There was no difference between the 2 groups in terms of engraftment, aGvHD and cGvHD, VOD, hemorrhagic cystitis, infections, and relapse. The 5‐year OS of MUD transplantation and HAPLO transplantation groups was found 65.8% and 71.1%, respectively (log‐rank 0.51). The 5‐year RFS was 80.7% for MUD transplantation group and 86.9% for HAPLO transplantation group (log‐rank 0.48). There was no statistically significant difference between 2 groups according to TRM (25% MUD transplantation vs 16.3% HAPLO transplantation, log‐rank 0.48). These data suggest that survival for patients with high‐risk acute leukemia after HAPLO transplantation with ex vivo ɑβ⁺ T‐cell depletion is comparable with MUD transplantation.     

Subcutaneous immunoglobulin replacement following CD19‐specific chimeric antigen receptor T‐cell therapy for B‐cell acute lymphoblastic leukemia in pediatric patients

Twenty‐eight patients were maintained on subcutaneous immunoglobulin replacement for persistent B‐cell aplasia and agammaglobulinemia following CD19‐targeted chimeric antigen receptor T‐cell therapy for B‐cell lymphoblastic leukemia. Patients were transitioned from intravenous to subcutaneous immunoglobulin replacement at a median of 11.5 months (range, 4‐20). Increasing serum IgG level was significantly associated with a lower rate of sinopulmonary infection (P = 0.0072). The median serum IgG level during infection‐free periods was 1000 mg/dL (range, 720‐1430), which was significantly higher than IgG levels in patients with sinopulmonary infections. As such, we recommend maintaining a goal IgG level > 1000 mg/dL to provide optimal protection.     

Simple in vitro migration assay for neural crest cells and the opposite effects of all‐trans‐retinoic acid on cephalic‐ and trunk‐derived cells

Here, we describe a simple in vitro neural crest cell (NCC) migration assay and the effects of all‐trans‐retinoic acid (RA) on NCCs. Neural tubes excised from the rhombencephalic or trunk region of day 10.5 rat embryos were cultured for 48 h to allow emigration and migration of NCCs. Migration of NCCs was measured as the change in the radius (radius ratio) calculated from the circular spread of NCCs between 24 and 48 h of culture. RA was added to the culture medium after 24 h at embryotoxic concentrations determined by rat whole embryo culture. RA (10 μM) reduced the migration of cephalic NCCs, whereas it enhanced the migration of trunk NCCs, indicating that RA has opposite effects on these two types of NCCs.