Programmed cell death ligand 1 expression in aggressive pediatric non-Hodgkin lymphomas: frequency, genetic mechanisms, and clinical significance

Programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) are immunomodulatory molecules overexpressed in lymphomas and are promising immunotherapy targets for hematologic malignancies. However, studies of PD-1/PD-L1 overexpression and their clinical significance in aggressive pediatric non-Hodgkin lymphomas (NHL) are limited. We assessed PD-1/PD-L1 overexpression using immunohistochemistry in 68 aggressive pediatric NHL: ALK-positive anaplastic large cell lymphoma (ALK+ ALCL, n=8), Burkitt lymphoma (BL, n=27), and large B-cell lymphoma (LBCL) de novo LBCL, n=22 and diffuse LBCL arising as monomorphic post-transplant lymphoproliferative disorder [PTLD-DLBCL], n=11. In LBCL, correlations between PD-L1 overexpression and Epstein-Barr virus (EBV) status, cell of origin, stage, nodal status, overall survival (OS), and event-free survival (EFS) were examined. The genetic mechanisms of PD-L1 overexpression were investigated using targeted next-generation sequencing (NGS) and cytogenetic data. All ALK+ ALCL samples, 50.0% of de novo LBCL (11/22), 72.7% of PTLD-DLBCL (8/11), and no BL overexpressed PD-L1. Overexpressed PD-L1 correlated with EBV positivity (P=0.033) in LBCL and lower EFS in de novo LBCL (P=0.017). NGS of select LBCL revealed distinct somatic mutations and an ultra-hypermutated PTLD-DLBCL. Most cases with 9p24.1 copy gains overexpressed PD-L1 although some cases had no discernible genetic drivers of PD-L1 overexpression. Overexpressed PD-L1 is common in pediatric LBCL, associated with EBV positivity and 9p24.1 gains, and may have prognostic significance in de novo LBCL. Furthermore, diverse molecular mechanisms for PD-L1 overexpression in aggressive pediatric NHL can occur. Thus, additional studies exploring the therapeutic and prognostic significance and molecular mechanisms of PD-L1 overexpression in aggressive pediatric NHL are warranted

Genetic errors of immunity distinguish pediatric non-malignant lymphoproliferative disorders

Background Pediatric non-malignant lymphoproliferative disorders (PLPD) are clinically and genetically heterogeneous. Long-standing immune dysregulation and lymphoproliferation in children may be life-threatening, and a paucity of data exists to guide evaluation and treatment of children with PLPD. Objective The primary objective of this study was to ascertain the spectrum of genomic immunologic defects in PLPD. Secondary objectives included characterization of clinical outcomes and associations between genetic diagnoses and those outcomes. Methods PLPD was defined by persistent lymphadenopathy, lymph organ involvement, or lymphocytic infiltration for more than 3 months, with or without chronic or significant EBV infection. Fifty-one subjects from 47 different families with PLPD were analyzed using whole exome sequencing (WES). Results WES identified likely genetic errors of immunity in 51% to 62% of families (53% to 65% of affected children). Presence of a genetic etiology was associated with younger age and hemophagocytic lymphohistiocytosis. Ten-year survival for the cohort was 72.4%, and patients with viable genetic diagnoses had a higher survival rate (82%) compared to children without a genetic explanation (48%, p = 0.03). Survival outcomes for individuals with EBV-associated disease and no genetic explanation were particularly worse than outcomes for subjects with EBV-associated disease and a genetic explanation (17% vs. 90%; p = 0.002). Ascertainment of a molecular diagnosis provided targetable treatment options for up to 18 individuals and led to active management changes for 12 patients. Conclusion PLPD therefore defines children with high risk for mortality, and WES informs clinical risks and therapeutic opportunities for this diagnosis

Folate pathway polymorphisms and neuropsychological impairment after leukemia therapy

Neuropsychological impairment occurs in 20%-40% of childhood acute lymphoblastic leukemia (ALL) survivors, possibly mediated by folate depletion following methotrexate chemotherapy. We evaluated the relationship between two folate pathway polymorphisms and neuropsychological impairment after childhood ALL chemotherapy. Eighty-six childhood ALL survivors were recruited between 2004-2007 at Texas Children\u27s Hospital after exclusion for central nervous system leukemia, cranial irradiation, and age\u3c1 year at diagnosis. Neuropsychological evaluation at a median of 5.3 years off therapy included a parental questionnaire and the following child performance measures: Trail Making Tests A and B, Grooved Pegboard Test Dominant-Hand and Nondominant-Hand, and Digit Span subtest. We performed genotyping for polymorphisms in two folate pathway genes: reduced folate carrier (RFC1 80G\u3eA, rs1051266) and dihydrofolate reductase (DHFR Intron-1 19bp deletion). Fisher exact test, logistic regression, Student\u27s t-test, and ANOVA were used to compare neuropsychological test scores by genotype, using a dominant model to group genotypes. In univariate analysis, survivors with cumulative methotrexate exposure ≥9000 mg/m2 had an increased risk of attention disorder (OR=6.2, 95% CI 1.2 – 31.3), compared to survivors with methotrexate exposure \u3c9000 mg/m2. On average, female survivors scored 8.5 points higher than males on the Digit Span subtest, a test of working memory (p=0.02). The RFC1 80G\u3eA and DHFR Intron-1 deletion polymorphisms were not related to attention disorder or impairment on tests of attention, processing speed, fine motor speed, or memory. These data imply a strong relationship between methotrexate dose intensity and impairment in attention after childhood ALL therapy. We did not find an association between the RFC1 80G\u3eA or DHFR Intron-1 deletion polymorphisms and long-term neuropsychological impairment in childhood ALL survivors

Weight trends in a multiethnic cohort of pediatric acute lymphoblastic leukemia survivors: A longitudinal analysis.

BackgroundAs survival rates for childhood acute lymphoblastic leukemia (ALL) continue to improve, there is growing concern over the chronic health conditions that survivors face. Given that survivors of childhood ALL are at increased risk of cardiovascular complications and obesity, we sought to characterize BMI trends from diagnosis through early survivorship in a multi-ethnic, contemporary cohort of childhood ALL patients and determine if early weight change was predictive of long-term weight status.MethodsThe study population consisted of ALL patients aged 2-15 years at diagnosis who were treated with chemotherapy alone at Texas Children's Hospital. Each patient had BMI z-scores collected at diagnosis, 30-days post-diagnosis, and annually for five years. Linear regression models were estimated to evaluate the association between: 1) BMI z-score change in the first 30 days and BMI z-scores at five-years post-diagnosis; and 2) BMI z-score change in the first year post-diagnosis and BMI z-scores at five-years post-diagnosis.ResultsThis retrospective cohort study included longitudinal data from 121 eligible patients. The mean BMI z-scores for the population increased significantly (p-valueConclusionOur results suggest that weight gain within the first year after diagnosis is more strongly associated with long-term BMI than early weight gain (within 30 days). If confirmed, this information may help identify a window of time during therapy when ALL patients would benefit most from weight management directed interventions

Genetic markers in a multi-ethnic sample for childhood acute lymphoblastic leukemia risk

Genome-wide association studies have identified multiple risk loci for childhood acute lymphoblastic leukemia (ALL), but mostly in European/White populations, despite Hispanics having a greater risk. We re-examined single nucleotide polymorphisms (SNPs) of known associations with childhood ALL and known human leukocyte antigen (HLA) region lymphoma risk markers in a multi-ethnic population. Significant associations were found in two ARID5B variants (rs7089424 and rs10821936). We replicated a strong risk association in non-Hispanic White males with rs2395185, a protective marker for lymphoma. Another HLA region marker, rs2647012, showed a risk association among Hispanics only, while a strong protective association was found with rs1048456, a follicular lymphoma risk marker. Our study validated this new case-control sample by confirming genetic markers associated with childhood ALL, and yielded new associations with lymphoma markers. Despite positive results, our study did not provide any clues as to why Hispanics have a higher susceptibility to childhood leukemia, suggesting that environmental factors may have a strong contribution

Defining the Inflammatory Plasma Proteome in Pediatric Hodgkin Lymphoma.

Hodgkin lymphoma (HL) histopathology is characterized by rare malignant Reed–Sternberg cells among an inflammatory infiltrate. We hypothesized that characteristics of inflammation in pediatric HL lesions would be reflected by the levels of inflammatory cytokines or chemokines in pre-therapy plasma of children with HL. The study objectives were to better define the inflammatory pre-therapy plasma proteome and identify plasma biomarkers associated with extent of disease and clinical outcomes in pediatric HL. Pre-therapy plasma samples were obtained from pediatric subjects with newly diagnosed HL and healthy pediatric controls. Plasma concentrations of 135 cytokines/chemokines were measured with the Luminex platform. Associations between protein concentration and disease characteristics were determined using multivariate permutation tests with false discovery control. Fifty-six subjects with HL (mean age: 13 years, range 3–18) and 47 controls were analyzed. The cytokine/chemokine profiles of subjects with HL were distinct from controls, and unique cytokines/chemokines were associated with high-risk disease (IL-10, TNF-α, IFN-γ, IL-8) and slow early response (CCL13, IFN-λ1, IL-8). TNFSF10 was significantly elevated among those who ultimately relapsed and was significantly associated with worse event-free survival. These biomarkers could be incorporated into biologically based risk stratification to optimize outcomes and minimize toxicities in pediatric HL