Effect of umbilical cord blood stem cell transplantation on restenosis after endovascular interventional therapy for diabetic hindlimb vascular disease

This study aimed to investigate the mechanism of human umbilical cord blood stem cell (HUCBSC) transplantation on restenosis after percutaneous transluminal angioplasty (PTA) for diabetic hindlimb vascular disease in rabbits. After successfully preparing a rabbit model of diabetic hindlimb vascular disease, 16 rabbits were randomly assigned to two groups. Of these, 8 rabbits received PTA surgery alone (PTA group), and the other 8 rabbits received PTA and HUCBSC (PTA+HUCBSC group) treatments. Five more healthy rabbits were set as healthy control (HC group). Samples were collected after 4 weeks of treatment. The expressions of regulator of calcineurin 1 (RCAN1) and calcineurin A (CnA) in the diseased artery were detected by immunofluorescence staining. The distribution of HUCBSCs was observed by pathological examination in transplanted artery, distal artery, and liver. Cytology experiments were applied to assess the levels of JAK and STAT3, and the migration and proliferation of human aortic vascular smooth muscle cells (HA-VSMC). In the rabbit model of diabetic vascular lesions in the hindlimbs, we found the stenosis of the femoral artery became more and more serious with time, and the expression level of PCNA positive cells was also gradually increased. The expression levels of RCAN1 and CnA in the PTA+HUCBSC group were significantly lower than those in PTA group. HUCBSC inhibited the migration and proliferation of HA-VSMC via JAK/STAT3 pathway. After HUCBSC local transplantation, HUCBSC had no distal tissue distribution. HUCBSC transplantation may prevent restenosis after PTA of diabetic hindlimb vascular disease through JAK/STAT3 pathway.

Case Report: Metagenomic Next-Generation Sequencing in Diagnosis of Legionella pneumophila Pneumonia in a Patient After Umbilical Cord Blood Stem Cell Transplantation

We report a case of hospital-acquired Legionella pneumonia that was detected by metagenomic next-generation sequencing (mNGS) of blood from a 7-year-old girl after umbilical cord blood stem cell transplantation (UCBT) with myelodysplastic syndrome. UCBT is traditionally associated with an increased risk of infection, particularly during the first 3 months after transplantation. Controlling interstitial pneumonia and severe infection is the key to reducing patient mortality from infection. Legionella pneumophila can cause a mild cough to rapidly fatal pneumonia. After mNGS confirmed that the pathogen was L. pneumophila, azithromycin, cefoperazone sulbactam, and posaconazole were used for treatment, and the patient's temperature decreased and remained normal. The details of this case highlight the benefits of the timely use of metagenomic NGS to identify pathogens for the survival of immunocompromised patients.

Outcome of Sibling's and Unrelated Umbilical Cord Blood Stem Cell Transplantation Combined PBSC in Thalassemia Major and Related Factors Analysis:76 Cases Reported in Single Center

Objectives: At present, allogeneic hematopoietic stem cell transplantation is still the only way to cure thalassemia major (TM) patients. But in fact, less than half of the patients can find matched sibling or unrelated donors.Umbilical cord blood stem cells(UCB) is a potential source of stem cells.This paper was to explore effectiveness and compare the outcomes of sibling's and unrelated cord blood stem cell transplantation combined with PBSC in TM. Methods: From Jan. 2008 to Oct. 2019, the clinical data of 76 children with TM who were first underwent cord blood stem cell transplantation was analyzed retrospectively. As of Dec.31, 2019, the median follow-up time was 53 months. The NF-08-TM protocol with CY + Bu + flu + TT in conditioning, was used for sibling cord blood transplantation(CBT) in which the graft including fresh cord blood and PBSC from newborns. Haploid peripheral blood stem cells combined unrelated cord blood transplantation was carried out with NF-14-TM protocol added CY in day +3, day+ 4 days ,followed infusion of unrelated cord blood in + 6 day.The average infusion of cord blood mononuclear cells was 8.50×10^7 (2.73-20.30×10^7), of which CD34+cells were 2.42×10^5 (0.26-8.06×10^5). Unrelated cord blood mononuclear cells were 5.90×10^7 (0.77-11.35×10^7), of which CD34+ cells were 1.78×10^5 (0.17-4.44×10^5). The number of haploid mononuclear cells was 27.70×10^8 (8.80-63.18×10^8). SPSS 20.0 software was used to analyze the subjects' clinical characteristics, long-term survival rate, factors affecting umbilical cord blood implantation and related complications Results:Total of 45 cases of sibling CBT and 31 cases of unrelated CBT combined with haploid PBSC were enrolled. Two of the 76 thalassemia children died, with an OS of 96.3±2.6%, TFS93.8±3.1%; TMR was 3.7%. The OS of the sibling CBT group and the unrelated CBT group were 97.8 ± 2.2% and 90.0±9.9%, P=0.586; Meanwhile TFS were 93.3 ± 3.7% and 92.9±6.9%, P=0.589. Liver iron concentration (MRI-T2) in the unrelated CBT group was significantly correlated with delayed implantation of stem cells and delayed reconstruction of platelets (P=0.013 and P=0.034).There was no significant difference in the rate of delayed implantation of stem cells and granulocyte reconstruction between the unrelated CBT group and the sibling CBT group, but the rate of delayed platelet reconstruction in the unrelated CBT group was significantly higher than that in the sibling CBT group (P=0.002). The time of umbilical cord blood implantation in the unrelated CBT group was shorter than that in the sibling CBT group (24.32 days vs 37.67 days, P=0.058), but the platelet reconstruction in this group was slower than that in the sibling CBT group, with no statistically significant difference (P=0.061). In the ferritin level, the platelet reconstruction time in the unrelated CBT group was significantly higher than that in the sibling CBT group (P=0.031). Logistic regression analysis showed that ferrimin, umbilical cord blood sources, dose of umbilical cord blood mononuclear cells and acute GVHD were not risk factors for delayed implantation of stem cells (over 30 days).The incidence of acute and chronic GVHD in the unrelated CBT group was significantly higher than that in the sibling CBT group (P < 0.001 and P=0.034). The virus infection rate of the unrelated CBT group was significantly higher than that of the sibling CBT group (P=0.008). The infection of herpes simplex virus type I was common in sibling CBT, while cytomegalovirus was the main infectious virus in unrelated CBT. Conclusion:By increasing the dose of stem cells, the outcomes of TM after transplantation was favorable both in sibling and unrelated CBT group. Unrelated CBT combined with haploid PBSC can potentially reduce implantation time compared with sibling CBT. The strategies of prophylaxis and treatment of GVHD and cytomegalovirus infection should be strengthened. Iron overload may affect umbilical cord blood stem cell implantation and hematopoietic recovery. Figure 1 Disclosures No relevant conflicts of interest to declare.

LIG4 Syndrome: Clinical and Molecular Characterization in a Chinese Cohort

Background: DNA Ligase IV (LIG4) syndrome is a rare disease with few reports to date. Patients suffer from a broad spectrum of clinical features, including microcephaly, growth retardation, developmental delay, dysmorphic facial features, combined immunodeficiency, and malignancy predisposition. There is thought to be a potential association between genotypes and phenotypes. Here, we investigated the characteristics of LIG4 syndrome in a Chinese cohort.Results: All seven patients had growth restriction. Most patients (6/7) had microcephaly (< -3 SD). Recurrent bacterial infections of the lungs and intestines were the most common symptoms. One patient had myelodysplastic syndromes. One patient presented with an inflammatory bowel disease (IBD)-like phenotype. Patients presented with combined immunodeficiency. The proportions of naive CD4+ and naive CD8+ T cells decreased notably in five patients. All patients harbored compound heterozygous mutations in the LIG4 gene, consisting of a missense mutation (c.833G>T, p.R278L) and a deletion shift mutation, primarily c.1271-1275delAAAGA (p.K424Rfs). Two other deletion mutations, c.1144-1145delCT and c.1277-1278delAA, were novel. Patients with p.K424RfsX20/p.R278 might lead to milder dysmorphism, but more significant IgA/ IgM deficiency, compared with the frequent genotype p.R814X/p.K424RfsX20 reported. One patient underwent umbilical cord blood stem cell transplantation (UCBSCT) but died.Conclusions: This study reported the clinical and molecular characteristics of a Chinese cohort, further expanding the phenotypic and genotypic spectrum, and the understanding of genotype-to-phenotype correlations in LIG4 syndrome. The results may help to characterize the status of the disease in China.