T-Cell Receptor Rearrangements Determined Using Fragment Analysis in Patients With T-Acute Lymphoblastic Leukemia

Clinical features, laboratory characteristics, and outcome of ETP and TCRA/D aberrations in pediatric patients with T-acute lymphoblastic leukemia

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy with few accepted prognostic factors that limit the efficiency of therapy. The aim of the current study was to assess the clinical and laboratory features of T-cell receptor (TCR) aberrations and early T-cell precursor (ETP) subtype as well as their outcome to therapy.

METHODS

Sixty-three newly diagnosed pediatric T-ALL patients were assessed for the ETP status using immunophenotyping. Screening of TCRA/D aberrations was done by fluorescent in situ hybridization (FISH). The data were correlated to the patients' clinical features, response to treatment, and survival rates.

RESULTS

Seven patients (11%) had ETP-ALL. The ETP-ALL patients were older (P = 0.013), presented with lower white blood cell (WBC) count (P = 0.001) and lower percentage of peripheral blood (PB) blast cells (P = 0.037), more likely to have hyperdiploid karyotype (P = 0.009), and had been associated with TCRA/D gene amplification (P = 0.014) compared to other T-ALL patients. Of note, the same associations had been significantly observed in patients with TCRA/D gene amplification. Patients with TCRA/D amplification frequently coincided with TCRβ aberrations (P = 0.025). TCR-β aberrations were significantly associated with negative MRD at the end of induction compared to TCR-β-negative patients. There was a nonsignificant trend of ETP-positive cases to have lower overall survival (OS) (P = 0.06). Patients with TCR aberrations had no significant differences regarding disease-free survival (DFS) or OS rates compared to those with normal TCR.

CONCLUSION

ETP-ALL patients tend to have increased mortalities. There was no significant impact of TCR aberrations on the survival rates of the patients.

Ultrasensitive quantitation of FLT3-ITD mutation in patients with acute myeloid leukemia using ddPCR

BACKGROUND

FLT3-ITD mutations occur in 45-50% of cytogenetically normal AML patients. Conventional fragment analysis using capillary electrophoresis is routinely used to quantitate FLT3-ITD mutations. Fragment analysis however has limited sensitivity.

METHODS AND RESULTS

Here, FLT3-ITD was quantified in AML patients using an in-house developed ultra-sensitive droplet digital polymerase chain reaction assay (ddPCR). The allelic ratio of FLT3-ITD was also absolutely measured by both Fragment analysis and ddPCR. The sensitivity of ddPCR in quantitation of FLT3-ITD mutation was superior to Fragment analysis.

CONCLUSION

This study demonstrates the feasibility of using the described in-house ddPCR method to quantify the FLT3-ITD mutation and measure FLT3-ITD AR in AML patients.

The case of T-ALL presenting with NK phenotype after COVID-19 vaccination

NK-lymphoblastic leukemia/lymphoma (NK-LL) is an extremely rare hematopoietic tumor consisting of natural killer (NK) precursor cells, and their lineage overlaps with T-cells, making it challenging to diagnose. COVID-19 vaccination is recommended for people with a risk of aggravation such as cancer-bearing patients, including hematopoietic tumors. We present a 55-year-old man who had cervical lymph node swelling post vaccination for COVID-19. Hematological malignancy was suspected due to the presence of atypical lymphoid cells with an elevated IL-2R in laboratory data. Tumor cells were positive for CD7, CD56, cyCD3, and terminal deoxynucleotidyl transferase (TdT) evidenced through flow cytometry of the bone marrow and the lymph node. The histopathological findings showed monotonous tumor cell proliferation, the cells being positive for CD3 and TdT in the bone marrow and they were positive for CD3, TdT, and CD56 in lymph node. Even though these findings suggested NK-LL, clonal T-cell receptor (TCR) β gene rearrangement by Southern blot hybridization was observed in the bone marrow. TCRβ rearrangement led to the final diagnosis of T-cell lymphoblastic leukemia (T-ALL). The causal relationship between COVID-19 vaccination and carcinogenesis is not clear, and more cases need to be studied in order to elucidate the relationship between the two factors.

A Novel Risk Defining System for Pediatric T-Cell Acute Lymphoblastic Leukemia From CCCG-ALL-2015 Group

Objective

T-cell acute lymphoblastic leukemia (T-ALL) is a rare hematological malignancy with a poor prognosis. The present study aims to identify the precise risk grouping of children with T-ALL.

Methods

We analyzed the outcomes for 105 consecutive patients treated using the Chinese Children’s Cancer Group ALL-2015 (CCCG-ALL-2015) protocol registered with the Chinese Clinical Trial Registry (ChiCTR-IPR-14005706) between 2015 and 2020 in our center. Nine out of 21 clinical and biological indicators were selected for the new scoring system based on the analysis in this study.

Results

The 5-year overall survival (OS), event-free survival (EFS), and disease-free survival (DFS) rates for the 105 patients were 83.1 ± 4.8%, 72.4 ± 5.6%, and 78.4 ± 3.6%, respectively. Based on the new scoring system, 90 evaluable children were regrouped into low-risk (n=22), intermediate-risk (n=50), and high-risk (n=18) groups. The 5-year survival (OS, EFS, and RFS) rates for all patients in the low-risk group were 100%, significantly higher than the rates for those in the intermediate-risk group (91.2 ± 5.2%, 74.4 ± 8.6%, and 82.5 ± 6.2%, respectively) and high-risk group (59.0 ± 13.2%, 51.9 ± 12.4%, and 51.9 ± 12.4%, respectively) (all P values < 0.01).

Conclusion

The CCCG-ALL-2015 program significantly improved the treatment outcomes for childhood T-ALL as compared with the CCCG-ALL-2008 protocol. Our new refined risk grouping system showed better stratification among pediatric T-ALL patients and better potential in evaluating therapeutic efficacy.