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Objective:To investigate the influencing factors of delayed methotrexate (MTX) elimination after high-dose methotrexate (HD-MTX) treatment in children with acute lymphoblastic leukemia (ALL) and the effects of delayed MTX elimination and HD-MTX reduction on the prognosis of children with ALL.Methods:The clinical data of 242 children with ALL diagnosed and treated in Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology from January 2015 to June 2020 in accordance with the Chinese Children's Cancer Group study ALL 2015 (CCCG-ALL 2015) were retrospectively analyzed. Low risk and intermediate/high risk children respectively received 3 g/m 2 and 5 g/m 2 HD-MTX for 4 times, and the serum MTX concentration was monitored. The serum MTX concentration > 1 μmol/L at 44 h of administration was considered as the delayed elimination, which was divided into mild (> 1 μmol/L and ≤ 5 μmol/L), moderate (> 5 μmol/L and ≤ 10 μmol/L) and severe (> 10 μmol/L) delayed elimination. Univariate and multivariate logistic regression analysis were used to analyze the influencing factors of delayed MTX elimination, and univariate Cox proportional hazards model was used to analyze the related factors of ALL relapse. Results:The 242 children with ALL completed 962 times of HD-MTX chemotherapy. The median serum MTX concentration [ M ( Q1, Q3)] at 44 h of administration was 0.45 μmol/L (0.33 μmol/L, 0.72 μmol/L). The total incidence of delayed MTX elimination was 17.7% (170/962). The incidence of mild, moderate and severe delayed elimination was 13.8% (133/962), 2.6% (25/962) and 1.2% (12/962), respectively. Logistic regression analysis showed that age ≥ 7 years old ( OR = 1.68, 95% CI 1.17-2.41, P = 0.005), MTX dose >3 g/m 2 at each course ( OR = 2.14, 95% CI 1.52-3.03, P < 0.001) and the first course of HD-MTX chemotherapy ( OR = 2.05, 95% CI 1.43-2.93, P < 0.001) were independent risk factors for delayed MTX elimination. The median follow-up time was 50 months (34 months, 68 months), 12.8% (31/242) of the children relapsed, and the median relapse time was 30 months (30 months, 39 months). Univariate Cox regression analysis showed that there were no significant differences in the relapse rates among children with different gender, immunophenotype, risk, the number of delayed MTX elimination, and the completion of HD-MTX chemotherapy (the ratio of MTX average dose to initial planned dose) (all P > 0.05). Conclusions:The independent risk factors of delayed elimination of MTX in children with ALL are age ≥ 7 years old, MTX dose > 3 g/m 2 at each course and the first course of HD-MTX chemotherapy. Delayed elimination of MTX and reduction of HD-MTX have no significant effect on ALL relapse.
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OBJECTIVE@#To report on a case with severe hemophilia A (HA) due to a large duplication of F8 gene.@*METHODS@#Inversion detection, Sanger sequencing, and multiplex ligation-dependent probe amplification (MLPA) were used to detect the mutation in the proband and his mother.@*RESULTS@#The patient, a 7-year-old boy, was diagnosed with severe HA at 8 months. No inhibitor was developed over 150 exposure days. Intronic inversion detection and Sanger sequencing have failed to identify pathogenic variants, while MLPA revealed a large duplication [Ex 1_22 dup (2 copies)] in the proband, for which his mother was a carrier [Ex 1_22 dup (3 copies)]. Large duplications of the F8 gene have so far been found in 24 HA patients, all of whom had a severe phenotype, only one had a history of inhibitors.@*CONCLUSION@#Large duplications of F8 gene are associated with severe HA. The diagnostic rate for HA may be increased by MLPA.