Topical therapy and skin care for transplant-associated atopic dermatitis in children and adolescents.

BACKGROUND: New-onset allergic diseases, such as food allergy or atopic dermatitis, can develop after allogeneic transplantation. There are limited reports of new-onset atopic dermatitis after allogeneic hematopoietic stem cell transplantation in children and adolescents, and its treatment is yet to be established. The pathogenesis may differ from typical atopic dermatitis in terms of alloimmunity including graft-versus-host disease. METHODS: We present five children and adolescents with new-onset atopic dermatitis after allogeneic hematopoietic stem cell transplantation. The characteristics and clinical profiles of skin treatment after hematopoietic stem cell transplantation are summarized. RESULTS: Graft-versus-host disease prophylaxis included systemic tacrolimus for all patients. After hematopoietic stem cell transplantation, all patients achieved complete donor chimerism of the bone marrow and had acute graft-versus-host disease of the skin. After engraftment, all patients had skin lesions that met the international consensus diagnostic criteria for atopic dermatitis. None of the patients met the diagnostic criteria for chronic graft-versus-host disease. Topical therapy and skin care based on atopic dermatitis guidelines improved skin condition and atopic dermatitis severity scores in all patients. In addition, type 2 inflammatory markers improved accordingly. CONCLUSION: Topical therapy and skin care may be effective for transplant-related atopic dermatitis after hematopoietic stem cell transplantation. When extensive dermatitis is observed after hematopoietic stem cell transplantation, this treatment may avoid excessive immunosuppressive therapy if it meets the diagnostic criteria for atopic dermatitis.

Selective expansion of donor-derived regulatory T cells after allogeneic bone marrow transplantation in a patient with IPEX syndrome.

IPEX syndrome is a rare and fatal disorder caused by absence of regulatory T cells (Tregs) due to congenital mutations in the Forkhead box protein 3 gene. Here, we report a patient with IPEX syndrome treated with RIC followed by allogeneic BMT from an HLA-matched sibling donor. We could achieve engraftment and regimen-related toxicity was well tolerated. Although the patient was in mixed chimera and the ratio of donor cells in whole peripheral blood remained relatively low, selective and sustained expansion of Tregs determined as CD4+CD25+Foxp3+ cells was observed. Improvement in clinical symptoms was correlated with expansion of donor-derived Tregs and disappearance of anti-villin autoantibody, which was involved in the pathogenesis of gastrointestinal symptoms in IPEX syndrome. This clinical observation suggests that donor-derived Tregs have selective growth advantage in patients with IPEX syndrome even in mixed chimera after allogeneic BMT and contribute to the control of clinical symptoms caused by the defect of Tregs.

Gene therapy model of X-linked severe combined immunodeficiency using a modified foamy virus vector.

X-linked severe combined immunodeficiency (SCID-X1) is an inherited genetic immunodeficiency associated with mutations in the common cytokine receptor γ chain (γc) gene, and characterized by a complete defect of T and natural killer (NK) cells. Gene therapy for SCID-X1 using conventional retroviral (RV) vectors carrying the γc gene results in the successful reconstitution of T cell immunity. However, the high incidence of vector-mediated T cell leukemia, caused by vector insertion near or within cancer-related genes has been a serious problem. In this study, we established a gene therapy model of mouse SCID-X1 using a modified foamy virus (FV) vector expressing human γc. Analysis of vector integration in a human T cell line demonstrated that the FV vector integration sites were significantly less likely to be located within or near transcriptional start sites than RV vector integration sites. To evaluate the therapeutic efficacy, bone marrow cells from γc-knockout (γc-KO) mice were infected with the FV vector and transplanted into γc-KO mice. Transplantation of the FV-treated cells resulted in the successful reconstitution of functionally active T and B cells. These data suggest that FV vectors can be effective and may be safer than conventional RV vectors for gene therapy for SCID-X1.

A case series of CAEBV of children and young adults treated with reduced-intensity conditioning and allogeneic bone marrow transplantation: a single-center study.

BACKGROUND: Epstein-Barr virus (EBV)-infected T or NK cells cause chronic active EBV infection (CAEBV). Allogeneic hematopoietic stem cell transplantation (HSCT) is curative treatment for CAEBV patients. However, chemotherapy prior to HSCT and optimal conditioning regimen for allogeneic HSCT are still controversial. PATIENTS AND METHODS: We retrospectively analyzed five patients with CAEBV treated with reduced-intensity conditioning (RIC) consisted of fludarabine, cyclophosphamide, and low-dose total-body irradiation followed by allogeneic bone marrow transplantation in a single institute. Only one of five patients received chemotherapy prior to transplantation. We analyzed EBV-infected cells in a patient whose EBV load increased after HSCT by T-cell repertoire assay, separation of T-cell subpopulations, in situ hybridization and microsatellite analysis. RESULTS: All five patients achieved engraftment, complete chimera, and eradication of EBV load. All patients have been alive without any serious regimen-related toxicity for more than 16 months following HSCT. However, one patient transplanted from HLA-matched sibling donor developed clonal proliferation of CD4+ Vß3+ T cells caused by monoclonal EBV infection on day 99 after transplantation. Further analysis revealed that the CD4+ Vß3+ T cells selectively harbored EBV genome, and these infected cells were derived from donor T cells. CONCLUSIONS: Allogeneic HSCT with RIC is a safe and effective treatment for better overall survival and less regimen-related toxicity in patients with CAEBV. Our first pediatric case reported in the literature suggests that we should consider the possibility of persistent EBV infection in donor T cells as well as the relapse in recipient cells if EBV load increases after allogeneic HSCT.

Y chromosome-linked B and NK cell deficiency in mice.

There are no primary immunodeficiency diseases linked to the Y chromosome, because the Y chromosome does not contain any vital genes. We have established a novel mouse strain in which all males lack B and NK cells and have Peyer's patch defects. By 10 wk of age, 100% of the males had evident immunodeficiencies. Mating these immunodeficient males with wild-type females on two different genetic backgrounds for several generations demonstrated that the immunodeficiency is linked to the Y chromosome and is inherited in a Mendelian fashion. Although multicolor fluorescence in situ hybridization analysis showed that the Y chromosome in the mutant male mice was one third shorter than that in wild-type males, exome sequencing did not identify any significant gene mutations. The precise molecular mechanisms are still unknown. Bone marrow chimeric analyses demonstrated that an intrinsic abnormality in bone marrow hematopoietic cells causes the B and NK cell defects. Interestingly, fetal liver cells transplanted from the mutant male mice reconstituted B and NK cells in lymphocyte-deficient Il2rg(-/-) recipient mice, whereas adult bone marrow transplants did not. Transducing the EBF gene, a master transcription factor for B cell development, into mutant hematopoietic progenitor cells rescued B cell but not NK cell development both in vitro and in vivo. These Y chromosome-linked immunodeficient mice, which have preferential B and NK cell defects, may be a useful model of lymphocyte development.

Successful cord blood transplantation with reduced-intensity conditioning for childhood cerebral X-linked adrenoleukodystrophy at advanced and early stages.

Childhood cerebral ALD is a rapidly progressive and neurodegenerative disorder for which HSCT is the curative therapy if carried out at early stages. We successfully treated two patients of childhood cerebral ALD by CBT with RIC. The proband was a seven-yr-old boy whose brain MRI severity score (Loes score) was 14.5. Unrelated CBT was performed in five wk. To minimize conditioning regimen-related neurotoxicity, the combination of fludarabine (125 mg/m(2)), melphalan (140 mg/m(2)), and 4 Gy of brain-sparing TBI was used. The second patient was a six-yr-old brother of the proband. Four wk after the detection of a single small lesion (Loes score 1), he received unrelated CBT with the same RIC as the proband. In both patients, the engraftment was fast and stable, and severe complications were not observed. Furthermore, gadolinium-enhanced inflammation on brain MRI rapidly disappeared after CBT. Now, 20 and 13 months have passed after CBT, respectively, and both patients are neurologically stable. The RIC we used was sufficient for stable engraftment of cord blood and also tolerable even to the patient with advanced ALD. RIC-CBT should be considered for the patients with cerebral ALD at advanced stages, as well as those at early stages.

Refractory chronic immune thrombocytopenic purpura in a child with acute lymphoblastic leukemia.

Immune thrombocytopenic purpura (ITP) has been associated with several hematologic malignancies such as Hodgkin and non-Hodgkin lymphomas and chronic lymphocytic leukemia, but it is rare in children with acute lymphoblastic leukemia (ALL). Here, we report a 7-year-old girl with chronic ITP during early intensive phase of chemotherapy for ALL. She underwent splenectomy because thrombocytopenia had persisted even after treatment with intravenous immunoglobulin (IVIG), steroids, vincristine, rituximab, and anti-D antibody. After splenectomy, her platelet count had recovered, and maintenance therapy could be resumed with a support of IVIG. To our knowledge, this is the first child case of chronic ITP during chemotherapy for ALL and splenectomy was effective in this patient.