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Letters to the Editor
Wen et al.’s cohort which developed HLH 3 to 6 months after diagnosis of NKTCL, during or after treatment. The onset of HLH might be triggered by the initiation of chemotherapy that leads to loss of immune homeostasis and further aggravates T-cell dysfunction which may fur- ther lower the threshold for triggering HLH in lymphoma
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patients.6 It is possible that in the absence of chemother- apy in our patients, the activating effect of the ECSIT-T419 mutation on the NF-κB pathway is not strong enough to drive HLH. However, there were four ECSIT wild-type patients from Singapore who devel- oped HLH again after chemotherapy initiation.
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Figure 1. ECSIT-T419C is a germline mutation not associated with hemophagocytic lymphohistiocytosis in natural killer/T-cell lymphoma patients. (A) Sanger sequencing electropherogram profile for tumor-normal paired samples with heterozygous ECSIT-V140A mutation, identified as L12, L14, L20, L21, and L24 in Jiang et al.3 (B and C) Representative Sanger sequencing electropherogram profile for two tumor- peripheral blood (B) and buccal swab (C) samples for the ECSIT- V140A mutation from Singapore local hospitals and the Sun Yat-Sen University Cancer Center in Guangzhou, China. (D) Integrative Genomics Viewer (IGV) snap- shot centered around heterozygous germline ECSIT-T419C mutation of the paired tumor-normal exome sequencing data of sample NKT1 from Wen et al.2 Variant allele frequencies (VAF) were calculated from the number of variant-supporting/total read-counts at ECSIT-T419C. Aligned reads were colored pink according to the read-strand that they were aligned with onto the human reference genome. (E) No association between ECSIT mutation and clinical characteristics of natural killer/T-cell lymphoma patients in Singapore and Taiwan. ECSIT: evolutionarily conserved signaling intermediate in Toll pathway; IPI: international prognostic index, ECOG: Eastern Cooperative Oncology Group, HLH: hemophagocytic lymphohistiocytosis, Mut: mutant; WT: wild-type.
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haematologica | 2021; 106(6)