Endobronchial mucosal nodules and actinomycosis in a child with activated phosphatidylinositol 3-kinase delta syndrome (APDS).

In this report, we describe a case of a 5-year-old girl with poor growth and unresolving pneumonia. Bronchoscopy showed numerous endobronchial mucosal nodules, consisting of dense lymphoid infiltrates. Bacterial culture of the nodule biopsy suggested endobronchial actinomycosis. Genetic test confirmed the diagnosis of APDS.

Epidemiology and outcomes of pediatric transplant-associated thrombotic microangiopathy in Hong Kong.

BACKGROUND: Transplant-associated thrombotic microangiopathy (TA-TMA) is an under-recognized yet potentially devastating complication of hematopoietic stem cell transplantation (HSCT) which had increased awareness in recent years. This report summarizes the demographics and outcomes of pediatric TA-TMA in Hong Kong. METHODS: All patients aged below 18 years who underwent HSCT in the Hong Kong Children's Hospital and were diagnosed to have TA-TMA during the 2-year period from April 1, 2019 to March 31, 2021 were included. RESULTS: A total of 73 transplants (51 allogeneic and 22 autologous) in 63 patients had been performed. Six patients (four males and two females) developed TA-TMA at a median duration of 2.5 months post-HSCT. The incidence rate was 9.52%. Of the six TA-TMA patients, five underwent allogenic one underwent autologous HSCT, respectively. Three of them were histologically proven. All four patients with cyclosporine had stopped the drug once TA-TMA was suspected. Median six doses of eculizumab were administered to five out of six patients. Three patients died (two due to fungal infection and one due to acute-on-chronic renal failure) within 3 months upon diagnosis of TA-TMA. Among three survivors, two stabilized with mild stage 2 chronic kidney disease (CKD) while the other suffered from stage 5 end-stage CKD requiring lifelong dialysis. CONCLUSION: In conclusion, recognition and diagnosis of TA-TMA are challenging. Early recognition and prompt administration of complement blockage with eculizumab may be beneficial in selected cases. Further prospective research studies are recommended to improve the management and outcomes of TA-TMA.

Neurological complications in Chinese children undergoing hematopoietic stem cell transplantation.

BACKGROUND: Hematopoietic stem cell transplantation, despite being a curative treatment for various pediatric disorders, is associated with significant acute and chronic complications. METHODS: This retrospective review of 196 hematopoietic stem cell transplantation episodes (144 allogeneic, 52 autologous) performed in a tertiary pediatric unit focused on neurological symptoms and complications occurred from the start of conditioning to within 3 years of transplantation. Indications for transplantation included both benign and malignant diseases. For episodes involving allogeneic transplantation, 42% of donors were matched-unrelated, 19% were matched-sibling, and 12% were haploidentical.  RESULTS: Neurological complications developed in 17% of all hematopoietic stem cell transplantation episodes. Tumors of central nervous system and leukemia or lymphoma were two indications reported to have higher incidence of 42% and 21%, respectively. The occurrence of neurological complications was significantly associated with primary diagnosis (p = 0.01), central nervous system involvement by underlying disease (p = 0.001), and radiation-based conditioning (p = 0.018). Upon multivariate analysis, central nervous system involvement by underlying disease remained to be the only significant factor (p = 0.019), while radiation-based containing conditioning (p = 0.029) is revealed to be associated when considering allogeneic transplantation alone. Pre-transplant central nervous system-directed treatment, allogeneic versus autologous donor, stem cell source, donor type, busulfan use, and cyclosporin use were not significantly associated with neurological complications. Patients with neurological complications were also found to have an inferior 2-year overall survival (53.9% ± 8.8% versus 63.8% ± 4.2%; p = 0.016). CONCLUSION: Neurological complications were common in pediatric hematopoietic stem cell transplantation and were associated with adverse outcome; non-radiation containing conditioning regimens might be beneficial in mitigating the risk of such complications.

Exosomes derived from Vδ2-T cells control Epstein-Barr virus-associated tumors and induce T cell antitumor immunity.

Treatment of life-threatening Epstein-Barr virus (EBV)-associated tumors remains a great challenge, especially for patients with relapsed or refractory disease. Here, we found that exosomes derived from phosphoantigen-expanded Vδ2-T cells (Vδ2-T-Exos) contained death-inducing ligands (FasL and TRAIL), an activating receptor for natural killer (NK) cells (NKG2D), immunostimulatory ligands (CD80 and CD86), and antigen-presenting molecules (MHC class I and II). Vδ2-T-Exos targeted and efficiently killed EBV-associated tumor cells through FasL and TRAIL pathways and promoted EBV antigen-specific CD4 and CD8 T cell expansion. Administration of Vδ2-T-Exos effectively controlled EBV-associated tumors in Rag2-/-γc-/- and humanized mice. Because expanding Vδ2-T cells and preparing autologous Vδ2-T-Exos from cancer patients ex vivo in large scale is challenging, we explored the antitumor activity of allogeneic Vδ2-T-Exos in humanized mouse cancer models. Here, we found that allogeneic Vδ2-T-Exos had more effective antitumor activity than autologous Vδ2-T-Exos in humanized mice; the allogeneic Vδ2-T-Exos increased the infiltration of T cells into tumor tissues and induced more robust CD4 and CD8 T cell-mediated antitumor immunity. Compared with exosomes derived from NK cells (NK-Exos) with direct cytotoxic antitumor activity or dendritic cells (DC-Exos) that induced T cell antitumor responses, Vδ2-T-Exos directly killed tumor cells and induced T cell-mediated antitumor response, thus resulting in more effective control of EBV-associated tumors. This study provided proof of concept for the strategy of using Vδ2-T-Exos, especially allogeneic Vδ2-T-Exos, to treat EBV-associated tumors.

Genome-wide search followed by replication reveals genetic interaction of CD80 and ALOX5AP associated with systemic lupus erythematosus in Asian populations.

OBJECTIVES: Genetic interaction has been considered as a hallmark of the genetic architecture of systemic lupus erythematosus (SLE). Based on two independent genome-wide association studies (GWAS) on Chinese populations, we performed a genome-wide search for genetic interactions contributing to SLE susceptibility. METHODS: The study involved a total of 1 659 cases and 3 398 controls in the discovery stage and 2 612 cases and 3 441 controls in three cohorts for replication. Logistic regression and multifactor dimensionality reduction were used to search for genetic interaction. RESULTS: Interaction of CD80 (rs2222631) and ALOX5AP (rs12876893) was found to be significantly associated with SLE (OR_int=1.16, P_int_all=7.7E-04 at false discovery rate<0.05). Single nuclear polymorphism rs2222631 was found associated with SLE with genome-wide significance (P_all=4.5E-08, OR=0.86) and is independent of rs6804441 in CD80, whose association was reported previously. Significant correlation was observed between expression of these two genes in healthy controls and SLE cases, together with differential expression of these genes between cases and controls, observed from individuals from the Hong Kong cohort. Genetic interactions between BLK (rs13277113) and DDX6 (rs4639966), and between TNFSF4 (rs844648) and PXK (rs6445975) were also observed in both GWAS data sets. CONCLUSIONS: Our study represents the first genome-wide evaluation of epistasis interactions on SLE and the findings suggest interactions and independent variants may help partially explain missing heritability for complex diseases.

Autologous cord blood transplantation for metastatic neuroblastoma.

Auto-SCT is a common approach for metastatic neuroblastoma with the intention to rescue hematopoiesis after megadose chemotherapy. PBSC or BM is the usual stem cell source for auto-SCT. Auto-CBT for neuroblastoma has very rarely been performed. Currently, case reports are available for two patients only. We performed 13 auto-SCTs for high-risk neuroblastoma from 2007 to 2013, including four cases of metastatic neuroblastoma aged 11-64 months treated with auto-CBT. All four patients had partial or CR to upfront treatments before auto-CBT. Nucleated cell dose and CD34+ cell dose infused were 2.8-8.7 × 10(7) /kg and 0.36-3.9 × 10(5) /kg, respectively. Post-thawed viability was 57-76%. Neutrophil engraftment (>0.5 × 10(9) /L) occurred at 15-33 days, while platelet engraftment occurred at 31-43 days (>20 × 10(9) /L) and 33-65 days (>50 × 10(9) /L) post-transplant, respectively. There was no severe acute or chronic complication. Three patients survived for 1.9-7.7 yr without evidence of recurrence. One patient relapsed at 16 months post-transplant and died of progressive disease. Cord blood may be a feasible alternative stem cell source for auto-SCT in patients with stage 4 neuroblastoma, and outcomes may be improved compared to autologous PBSC or BM transplants.

Three SNPs in chromosome 11q23.3 are independently associated with systemic lupus erythematosus in Asians.

Systemic lupus erythematosus (SLE) has a complex etiology and is affected by both genetic and environmental factors. Although more than 40 loci have shown robust association with SLE, the details of these loci, such as the independent contributors and the genes involved, are still unclear. In this study, we performed meta-analysis of two existing genome-wide association studies (GWASs) on Chinese Han populations from Hong Kong and Anhui, China, and followed the findings by further replication on three additional Chinese and Thailand cohorts with a total of 4254 cases and 6262 controls matched geographically and ethnically. We discovered multiple susceptibility variants for SLE in the 11q23.3 region, including variants in/near PHLDB1 (rs11603023, P(_combined) = 1.25E-08, OR = 1.20), DDX6 (rs638893, P(_combined) = 5.19E-07, OR = 1.22) and CXCR5 (rs10892301, P(_combined) = 2.51E-08, OR = 0.85). Genetic contributions from the newly identified variants were all independent of SNP rs4639966, whose association was reported from the previous GWAS. In addition, the three newly identified variants all showed independent association with the disease through modeling by both stepwise and conditional logistic regression. The presence of multiple independent variants in this region emphasizes its role in SLE susceptibility, and also hints the possibility that distinct biological mechanisms might be involved in the disease involving this genomic region.

Epistatic interaction between genetic variants in susceptibility gene ETS1 correlates with IL-17 levels in SLE patients.

T-helper cells that produce IL-17 (Th17 cells) are a subset of CD4(+) T-cells with pathological roles in autoimmune diseases including systemic lupus erythematosus (SLE), and ETS1 is a negative regulator of Th17 cell differentiation. Our previous work on genome-wide association study (GWAS) identified two variants in the ETS1 gene (rs10893872 and rs1128334) as being associated with SLE. However, like many other risk alleles for complex diseases, little is known on how these genetic variants might affect disease pathogenesis. In this study, we examined serum IL-17 levels from 283 SLE cases and observed a significant correlation between risk variants in ETS1 and serum IL-17 concentration in patients, which suggests a potential mechanistic link between these variants and the disease. Furthermore, we found that the two variants act synergistically in influencing IL-17 production, with evidence of significant genetic interaction between them as well as higher correlation between the haplotype formed by the risk alleles and IL-17 level in patient serum. In addition, the correlation between ETS1 variants and IL-17 level seems to be more significant in SLE patients manifesting renal involvement, dsDNA autoantibody production or early-onset.

Genome-wide association study in Asian populations identifies variants in ETS1 and WDFY4 associated with systemic lupus erythematosus.

Systemic lupus erythematosus is a complex and potentially fatal autoimmune disease, characterized by autoantibody production and multi-organ damage. By a genome-wide association study (320 patients and 1,500 controls) and subsequent replication altogether involving a total of 3,300 Asian SLE patients from Hong Kong, Mainland China, and Thailand, as well as 4,200 ethnically and geographically matched controls, genetic variants in ETS1 and WDFY4 were found to be associated with SLE (ETS1: rs1128334, P = 2.33x10(-11), OR = 1.29; WDFY4: rs7097397, P = 8.15x10(-12), OR = 1.30). ETS1 encodes for a transcription factor known to be involved in a wide range of immune functions, including Th17 cell development and terminal differentiation of B lymphocytes. SNP rs1128334 is located in the 3'-UTR of ETS1, and allelic expression analysis from peripheral blood mononuclear cells showed significantly lower expression level from the risk allele. WDFY4 is a conserved protein with unknown function, but is predominantly expressed in primary and secondary immune tissues, and rs7097397 in WDFY4 changes an arginine residue to glutamine (R1816Q) in this protein. Our study also confirmed association of the HLA locus, STAT4, TNFSF4, BLK, BANK1, IRF5, and TNFAIP3 with SLE in Asians. These new genetic findings may help us to gain a better understanding of the disease and the functions of the genes involved.