The Viral Load of Epstein-Barr Virus in Blood of Children after Hematopoietic Stem Cell Transplantation.

Objective: To detect the Epstein-Barr virus (EBV) viral load of children after hematopoietic stem cell transplantation (HSCT) using chip digital PCR (cdPCR). Methods: The sensitivity of cdPCR was determined using EBV plasmids and the EBV B95-8 strain. The specificity of EBV cdPCR was evaluated using the EBV B95-8 strain and other herpesviruses (herpes simplex virus 1, herpes simplex virus 2, varicella zoster virus, human cytomegalovirus, human herpesvirus 6, and human herpesvirus 7). From May 2019 to September 2020, 64 serum samples of children following HSCT were collected. EBV infection and the viral load of serum samples were detected by cdPCR. The epidemiological characteristics of EBV infections were analyzed in HSCT patients. Results: The limit of detection of EBV cdPCR was 110 copies/mL, and the limit of detection of EBV quantitative PCR was 327 copies/mL for the pUC57-BALF5 plasmid. The result of EBV cdPCR was up to 121 copies/mL in the EBV B95-8 strain, and both were more sensitive than that of quantitative PCR. Using cdPCR, the incidence of EBV infection was 18.75% in 64 children after HSCT. The minimum EBV viral load was 140 copies/mL, and the maximum viral load was 3,209 copies/mL using cdPCR. The average hospital stay of children with EBV infection (184 ± 91 days) was longer than that of children without EBV infection (125 ± 79 days), P = 0.026. Conclusion: EBV cdPCR had good sensitivity and specificity. The incidence of EBV infection was 18.75% in 64 children after HSCT from May 2019 to September 2020. EBV cdPCR could therefore be a novel method to detect EBV viral load in children after HSCT.

Clinical outcomes of individualized busulfan-dosing in hematopoietic stem cell transplantation in Chinese children undergoing with therapeutic drug monitoring.

To identify relationships between busulfan (Bu) exposure and outcomes of a cohort pediatric patients receiving hematopoietic stem cell transplantation (HSCT), along with a targeted busulfan-based conditioning regimen. We retrospectively evaluated targeted busulfan concentrations in 53 pediatric patients (age 0.4-16 years) who received busulfan 4 times daily according to recommended weight-based doses in a single-center analysis between 2018 and 2020. In this trial, individual busulfan pharmacokinetics were performed following dose 5 of the conditioning regimen. Twenty four of 53 patients (45.3%) studies did not require dose adjustments. Equal number of patients (24/53) required one dose adjustments while two-dose adjustment applied for 5 of 53 (9.4%). Twenty-one percent of the patients exhibited ll-lV aGVHD. The incidence of veno-occlusive disease (VOD) was in 3.8% of the 53 patients, while incidence of hemorrhagic cystitis (II-III) reached to 9.7%. Engraftment was successful in 98% of the 53 patients with relapse in 2% of cases. The probability of overall survival and disease-free survival at day 100 was 96% and 94%, respectively. In conclusion, therapeutic drug monitoring (TDM) and individualization of Bu dosage are essential to improve the efficacy and safety of busulfan-based regimen in Chinese pediatric HSCT recipients.

[Suppression of survivin gene in leukemia cells by small interfering RNA].

OBJECTIVE: To evaluate the impact of specific siRNA on survivin gene in transfected leukemia cells. METHOD: The small interfering RNA (siRNA) targeted survivin mRNA was synthesized in vitro and was transfected into K562 cell by Hiperfect into human leukemia cell line K562, which has high survivin expression level. The level of survivin mRNA expression was determined by quantitative reverse transcription polymerase chain reaction (RT-PCR) with SYBR GREEN I. The apoptosis index of cytotrophoblasts were determined and analyzed by FCM (Annexin V-FITC/PI staining methods). The cell proliferation was examined by MTT at 48 h and 72 h after transfection. RESULT: The level of mRNA expression was significantly inhibited by the siRNA 48 h and 72 h after transfection, the suppression rate of survivin mRNA separately reached 85.21%, 94.35% mensurated by quantitative RT-PCR with SYBR GREEN I, cell proliferation was inhibited significantly by 45.02% and 50.88%, respectively, the apoptotic rate detected by Annexin V-FITC assay reached 12.28%and 21.55%, respectively. CONCLUSION: The chemosynthesized siRNA targeting survivin could significantly down-regulate survivin mRNA. Survivin siRNA was able to inhibit the proliferation of leukemia cell line K562. Survivin may become a new target for leukemia gene therapy.