Tomonari Shigemura

Caspase recruitment domain–containing protein 9 (CARD9) deficiency is classically characterized by chronic mucocutaneous candidiasis (CMC) and invasive Candida infections, including central nervous system (CNS) disease. Susceptibility to mycobacterial infection has not been considered a defining feature of CARD9 deficiency. We describe a patient with a typical clinical phenotype of CARD9 deficiency associated with compound heterozygous variants in CARD9, initially presenting with CMC and later manifesting CNS candidiasis, complicated by a concurrent CNS infection caused by Mycobacterium intracellulare. This unexpected finding prompted detailed immunological analyses to determine whether the mycobacterial infection represented a coincidental event or reflected an underlying susceptibility. Immunological studies demonstrated preserved neutrophil nicotinamide adenine dinucleotide phosphate (NADPH) oxidase–dependent reactive oxygen species production, whereas bactericidal/permeability-increasing protein (BPI) was uniquely and markedly reduced among neutrophil antimicrobial proteins. In parallel, monocyte-derived dendritic cells exhibited impaired tumor necrosis factor-α (TNF-α) production in response to mycobacterial stimulation, suggesting impaired cytokine responses downstream of CARD9. These findings suggest that impaired dendritic cell cytokine responses to mycobacteria, together with markedly reduced neutrophil BPI content, may have contributed to the development of M. intracellulare infection in this patient. Our study highlights a potential mechanism underlying susceptibility to mycobacterial infection in CARD9 deficiency.

Epstein‐Barr virus‐associated post‐transplant lymphoproliferative disorder (EBV‐PTLD) is increasingly recognized as a life‐threatening complication after transplantation. Most areas affected by EBV‐PTLD are lymph nodes, with occasional reports of extranodal lesions such as the gastrointestinal tract and central nervous system; however, orbital regions are extremely rare. We report a case of EBV‐PTLD in a cord blood transplant recipient with a tumor in the upper right eyelid. Ultimately, eye symptoms were the first signs of PTLD. Transplant physicians should consider the possibility of PTLD when encountering an orbital lesion.

Post-transplant early immune disorders and engraftment failure/delay are major issues in unrelated umbilical cord blood transplantation (UCBT). We evaluated graft-versus-host disease (GVHD) prophylaxis approaches after UCBT by comparing UCBT outcomes with GVHD prophylaxis using tacrolimus plus methylprednisolone (Tac/mPSL, n = 32) to that with Tac plus methotrexate (Tac/MTX, n = 31) at a single pediatric transplantation center. The 30-day cumulative incidence rates of neutrophil engraftment and median neutrophil engraftment times in the Tac/mPSL and Tac/MTX groups were 70.1% and 90.3% and 19 and 17 days, respectively (p = 0.09). Pre-engraftment immune reactions (PIR) and acute GVHD were improved with Tac/MTX; PIR incidence (p = 0.020) and cumulative incidence of 100-day acute GVHD (grade II–IV, 38.7% vs 68.8%, p = 0.045; grade III–IV, 9.7% vs 34.4%, p = 0.021) were significantly lower in the Tac/MTX group than in the Tac/mPSL group. However, the incidence rates of relapse (p = 0.921) and cytomegalovirus reactivation (p = 0.908), and the estimated overall (p = 0.87) and event-free survival (p = 0.88) were comparable between the two groups. These data indicate that GVHD prophylaxis with Tac/MTX is associated with favorable results, including reduced PIR and acute GVHD incidence after UCBT, without adverse effects.

Dedicator of cytokinesis 8 (DOCK8) deficiency (MIM #243700) is a rare disease, leads to a combined primary immunodeficiency (PID), and accounts for the autosomal recessive-hyper immunoglobulin E syndrome (AR-HIES). DOCK8 deficiency status characterizes by recurrent infections, atopy, and risk of cancer. Lymphoproliferative disease complicating PID, is difficult to diagnose. Our aim is to present a rare case of PID, and to the best of our knowledge, she is the first case of DOCK8 deficiency from Iraq. The genetic diagnosis was carried out in Japan using dried blood spot-based DNA transfer and whole-exome sequencing. An 11-year-old Iraqi girl, of double first-cousin-parents, had a history of severe eczema, food allergy, and repeated infections. She presented with a jaw mass, bilateral cervical and axillary lymphadenopathy, and immunoglobulin (Ig) assays of 20, 3.3 and 1.7-fold above maximum normal level for age of IgE, IgA and IgG, respectively, along with a low IgM, eosinophilia and lymphopenia. Based on the jaw mass biopsy, non-Hodgkin lymphoma was suggested in Iraq, whereas histopathological re-evaluation in Japan revealed the diagnosis of a polyclonal reactive proliferation spectrum of lymphoproliferative disorders/plasmacytic hyperplasia, complicating PID. Whole-exome sequencing supported the diagnosis of PID by identifying a homozygous DOCK8 mutation with previously reported pathogenicity (NM_203447:c.3332delT, p.Phe1113Leufs*2), that may be attributed to consanguinity. International collaboration using an effective DNA transportation technique and next-generation sequencing was the key to pinpoint the diagnosis of DOCK8 deficiency. Our case asserted that careful pathogenetic evaluation, in an advanced setting, was crucial for ruling out the neoplastic process. Pediatricians in areas with a high prevalence of consanguinity marriage should have a high index of suspicion of DOCK8 deficiency in patients with recalcitrant eczema, and frequent respiratory and skin infectious episodes.

Summary: We established mutated and non‐mutated induced pluripotent stem cell (iPSC) clones from a patient with PTPN11 (c.226G>A)‐mutated juvenile myelomonocytic leukaemia (JMML). Both types of iPSCs fulfilled the quality criteria. Mutated iPSC colonies generated significantly more CD34⁺ and CD34⁺CD45⁺ cells compared to non‐mutated iPSC colonies in a culture coated with irradiated AGM‐S3 cells to which four growth factors were added sequentially or simultaneously. The haematopoietic differentiation potential of non‐mutated JMML iPSC colonies was similar to or lower than that of iPSC colonies from a healthy individual. The PTPN11 mutation coexisted with the OSBP2 c.389C>T mutation. Zinc‐finger nuclease‐mediated homologous recombination revealed that correction of PTPN11 mutation in iPSCs with PTPN11 and OSBP2 mutations resulted in reduced CD34⁺ cell generation to a level similar to that obtained with JMML iPSC colonies with the wild‐type of both genes, and interestingly, to that obtained with normal iPSC colonies. Transduction of the PTPN11 mutation into JMML iPSCs with the wild‐type of both genes increased CD34⁺ cell production to a level comparable to that obtained with JMML iPSC colonies harbouring the two genetic mutations. Thus, PTPN11 mutation may be the most essential abnormality to confer an aberrant haematopoietic differentiation potential in this disorder.

Background: Encouraging responses to histone deacetylase inhibitors have been reported for hematologic malignancies. Here, we report effects of panobinostat and 5‐azacytidine on the proliferation of juvenile myelomonocytic leukemia (JMML) CD34⁺ cells.Procedure: We previously reported that stimulation of JMML CD34⁺ cells with stem cell factor and thrombopoietin on irradiated murine AGM‐S3 cells led to substantial expansion of JMML CD34⁺ cells that contained leukemic stem cells capable of transplantation into immunodeficient mice. Using this culture system, we evaluated effects of panobinostat and 5‐azacytidine on the proliferation of JMML CD34⁺ cells.Results: Panobinostat dose dependently reduced the numbers of day 7 CD34⁺ cells generated under stimulation of hematopoietic growth factors on AGM‐S3 cells in all eight patients with JMML. These patients possessed various genetic and/or karyotypic abnormalities. CD34⁺CD38⁻ cells were substantially more sensitive to panobinostat at 10 and 20 nM than CD34⁺CD38⁺ cells. Panobinostat, however, failed to influence the ability of AGM‐S3 cells to stimulate JMML CD34⁺ cell production. In contrast to HL60 cells, apoptosis and cell cycle arrest in panobinostat‐mediated inhibition were at low levels in JMML. The inhibitor also suppressed the factor‐dependent proliferation of normal CD34⁺ cells on AGM‐S3 cells. Meanwhile, no substantial inhibitory effects of 5‐azacytidine on the growth of JMML CD34⁺ cells were observed.Conclusions: These results demonstrate that panobinostat directly suppresses the growth of JMML CD34⁺ cells, in particular CD34⁺CD38⁻ cells, regardless of the genetic abnormality type, suggesting that it is a useful antileukemic drug to target JMML stem cells at a pretransplant stage.