Langerhans cell histiocytosis: NACHO update on progress, chaos, and opportunity on the path to rational cures.

Langerhans cell histiocytosis (LCH) is a myeloid neoplastic disorder characterized by lesions with CD1a-positive/Langerin (CD207)-positive histiocytes and inflammatory infiltrate that can cause local tissue damage and systemic inflammation. Clinical presentations range from single lesions with minimal impact to life-threatening disseminated disease. Therapy for systemic LCH has been established through serial trials empirically testing different chemotherapy agents and durations of therapy. However, fewer than 50% of patients who have disseminated disease are cured with the current standard-of-care vinblastine/prednisone/(mercaptopurine), and treatment failure is associated with long-term morbidity, including the risk of LCH-associated neurodegeneration. Historically, the nature of LCH-whether a reactive condition versus a neoplastic/malignant condition-was uncertain. Over the past 15 years, seminal discoveries have broadly defined LCH pathogenesis; specifically, activating mitogen-activated protein kinase pathway mutations (most frequently, BRAFV600E) in myeloid precursors drive lesion formation. LCH therefore is a clonal neoplastic disorder, although secondary inflammatory features contribute to the disease. These paradigm-changing insights offer a promise of rational cures for patients based on individual mutations, clonal reservoirs, and extent of disease. However, the pace of clinical trial development behind lags the kinetics of translational discovery. In this review, the authors discuss the current understanding of LCH biology, clinical characteristics, therapeutic strategies, and opportunities to improve outcomes for every patient through coordinated agent prioritization and clinical trial efforts.

Genetic errors of immunity distinguish pediatric nonmalignant lymphoproliferative disorders.

BACKGROUND: Pediatric nonmalignant lymphoproliferative disorders (PLPDs) 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 Epstein-Barr virus (EBV) infection. Fifty-one subjects from 47 different families with PLPD were analyzed using whole exome sequencing. RESULTS: Whole exome sequencing 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 = .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 = .002). Ascertainment of a molecular diagnosis provided targetable treatment options for up to 18 individuals and led to active management changes for 12 patients. CONCLUSIONS: PLPD defines children at high risk for mortality, and whole exome sequencing informs clinical risks and therapeutic opportunities for this diagnosis.

Neutrophil gelatinase-associated lipocalin is elevated in children with acute kidney injury and sickle cell anemia, and predicts mortality.

Urine neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of acute kidney injury that has been adapted to a urine dipstick test. However, there is limited data on its use in low-and-middle-income countries where diagnosis of acute kidney injury remains a challenge. To study this, we prospectively enrolled 250 children with sickle cell anemia aged two to 18 years encompassing 185 children hospitalized with a vaso-occlusive pain crisis and a reference group of 65 children attending the sickle cell clinic for routine care follow up. Kidney injury was defined using serial creatinine measures and a modified-Kidney Disease Improving Global Outcome definition for sickle cell anemia. Urine NGAL was measured using the NGAL dipstick and a laboratory reference. The mean age of children enrolled was 8.9 years and 42.8% were female. Among hospitalized children, 36.2% had kidney injury and 3.2% died. Measured urine NGAL levels by the dipstick were strongly correlated with the standard enzyme-linked immunosorbent assay for urine NGAL (hospitalized children, 0.71; routine care reference, 0.88). NGAL levels were elevated in kidney injury and significantly increased across injury stages. Hospitalized children with a high-risk dipstick test (300ng/mL and more) had a 2.47-fold relative risk of kidney injury (95% confidence interval 1.68 to 3.61) and 7.28 increased risk of death (95% confidence interval 1.10 to 26.81) adjusting for age and sex. Thus, urine NGAL levels were found to be significantly elevated in children with sickle cell anemia and acute kidney injury and may predict mortality.

Acute kidney injury in hospitalized children with sickle cell anemia.

BACKGROUND: Children with sickle cell anemia (SCA) are at increased risk of acute kidney injury (AKI) that may lead to death or chronic kidney disease. This study evaluated AKI prevalence and risk factors in children with SCA hospitalized with a vaso-occlusive crisis (VOC) in a low-resource setting. Further, we evaluated whether modifications to the Kidney Disease: Improving Global Outcomes (KDIGO) definition would influence clinical outcomes of AKI in children with SCA hospitalized with a VOC. METHODS: We prospectively enrolled 185 children from 2 - 18 years of age with SCA (Hemoglobin SS) hospitalized with a VOC at a tertiary hospital in Uganda. Kidney function was assessed on admission, 24-48 h of hospitalization, and day 7 or discharge. Creatinine was measured enzymatically using an isotype-dilution mass spectrometry traceable method. AKI was defined using the original-KDIGO definition as ≥ 1.5-fold change in creatinine within seven days or an absolute change of ≥ 0.3 mg/dl within 48 h. The SCA modified-KDIGO (sKDIGO) definition excluded children with a 1.5-fold change in creatinine from 0.2 mg/dL to 0.3 mg/dL. RESULTS: Using KDIGO, 90/185 (48.7%) children had AKI with 61/185 (33.0%) AKI cases present on admission, and 29/124 (23.4%) cases of incident AKI. Overall, 23 children with AKI had a 1.5-fold increase in creatinine from 0.2 mg/dL to 0.3 m/dL. Using the sKDIGO-definition, 67/185 (36.2%) children had AKI with 43/185 (23.2%) cases on admission, and 24/142 (16.9%) cases of incident AKI. The sKDIGO definition, but not the original-KDIGO definition, was associated with increased mortality (0.9% vs. 7.5%, p = 0.024). Using logistic regression, AKI risk factors included age (aOR, 1.10, 95% CI 1.10, 1.20), hypovolemia (aOR, 2.98, 95% CI 1.08, 8.23), tender hepatomegaly (aOR, 2.46, 95% CI 1.05, 5.81), and infection (aOR, 2.63, 95% CI 1.19, 5.81) (p < 0.05). CONCLUSION: These results demonstrate that AKI is a common complication in children with SCA admitted with VOC. The sKDIGO definition of AKI in children with SCA was a better predictor of clinical outcomes in children. There is need for promotion of targeted interventions to ensure early identification and treatment of AKI in children with SCA.

Global health disparities in childhood cancers.

PURPOSE OF REVIEW: The high cure rates of children with cancer in high-income countries (HICs) are due to the impact of biomedical innovations on children with highly fatal diseases. We discuss why these innovations have not benefitted most children with cancer globally and propose broad strategies to reduce these disparities. RECENT FINDINGS: Over 85% of children with cancer in HIC are cured while less than 20% in many low-income countries survive the disease. Hence, childhood cancer survival is poor globally since over 80% of children with cancer live in low-income and middle-income countries (LMICs). Inadequate skilled workforce and health infrastructure across all disciplines of pediatrics in LMIC are the main reasons for these disparities. Although biological differences may contribute to these disparities as well, many are unconfirmed because they are confounded by differences in referral patterns and clinical capacity. HIC partnerships with LMIC that focus on locally based pediatrics training and clinical infrastructure building are beginning to close the gap. SUMMARY: Pediatric oncology is symbolic of the significant disparities in childhood survival arising from poverty, inadequate pediatric infrastructure, and skilled workforce in LMIC. Partnerships with HIC that build multidisciplinary pediatrics capacity and clinical infrastructure are beginning to make transformative improvements.

Impact of sickle cell disease on presentation and progression of paediatric HIV: a retrospective cohort study.

OBJECTIVES: HIV and sickle cell disease (SCD) are significant causes of morbidity and mortality in sub-Saharan Africa. Given their separate roles in immune dysregulation, our objective was to characterise the impact that SCD has on the presentation and progression of paediatric HIV. METHODS: The study was a retrospective cohort study (study period 2004-2018). Cases of HIV + and SCD-afflicted patients (HIV+/SCD+) were obtained via electronic chart review from a paediatric HIV clinic in Kampala, Uganda and matched 1:3 with HIV + controls without SCD (HIV+/SCD-). RESULTS: Thirty-five HIV+/SCD + subjects and 95 HIV+/SCD- controls were analysed (39% female (51/130), age 3.6 years (SD3.9)). At baseline, WHO clinical stage (64% total cohort Stage III/IV) and nutritional status (9.4% severe acute malnutrition) were similar for both groups, whereas HIV+/SCD + had higher though non-significant baseline CD4 count (1036 (SD713) vs 849 (SD638) cells/microlitre, P = 0.20, two-tailed t-test). There were 19 deaths, 6 (17%) HIV+/SCD + and 13 (14%) HIV+/SCD-, with unadjusted/adjusted models showing no significant difference. Nutritional progression and clinical stage progression showed no significant differences between groups. Kaplan-Meier analysis showed a slower rate of treatment failures in the HIV+/SCD + cohort (P = 0.11, log-rank survival test). Trajectory analysis showed that in the time period analysed, the HIV+/SCD + cohort showed a more rapid rise and higher total CD4 count (P = 0.012, regression analysis). CONCLUSION: The study suggests that SCD does not adversely affect the progression of HIV in patients on ART. Further, HIV+/SCD + achieved higher CD4 counts and fewer HIV treatment failures, suggesting physiological effects due to SCD might mitigate HIV progression.

OBJECTIFS: Le VIH et la drépanocytose (SCD) sont des causes importantes de morbidité et de mortalité en Afrique subsaharienne. Compte tenu de leurs rôles distincts dans la dérégulation immunitaire, notre objectif était de caractériser l'impact du SCD sur la présentation et la progression du VIH pédiatrique. MÉTHODES: Etude de cohorte rétrospective (période d'étude 2004-2018). Les cas de patients VIH+ atteints de SCD (VIH+/SCD+) ont été obtenus par analyse des dossiers électroniques dans une clinique pédiatrique du VIH à Kampala, en Ouganda et appariés dans une proportion 1:3 avec des témoins VIH+ sans SCD (VIH+/SCD-). RÉSULTATS: 35 sujets VIH+/SCD+ et 95 témoins VIH+/SCD- ont été analysés (39% de femmes (51/130), 3,6 ans d'âge (SD3,9)). Au départ, le stade clinique de l'OMS (64% de la cohorte totale au stade III/IV) et l'état nutritionnel (9,4% de malnutrition aiguë sévère) étaient similaires pour les deux groupes, tandis que les VIH+/SCD+ avaient un nombre de CD4 de base plus élevé mais non significatif (1036 (DS, 713) vs 849 (DS, 638) cellules/microlitre, p = 0,20, test t bilatéral). Il y a eu 19 décès, 6 (17%) VIH+/SCD+ et 13 (14%) VIH+/SCD-, avec des modèles non ajustés/ajustés ne montrant aucune différence significative. La progression nutritionnelle et la progression du stade clinique n'ont montré aucune différence significative entre les groupes. L'analyse de Kaplan-Meier a montré un taux d'échecs de traitement plus lent dans la cohorte VIH+/SCD+ (p = 0,11, test de survie log-rank). L'analyse de la trajectoire a montré que dans la période analysée, la cohorte VIH+/SCD+ a montré une augmentation plus rapide et un nombre total de CD4 plus élevé (p = 0,012, analyse de régression). CONCLUSION: L'étude suggère que SCD n'affecte pas négativement la progression du VIH chez les patients sous ART. De plus, les patients VIH+/SCD+ ont atteint un nombre plus élevé de CD4 et moins d'échecs de traitement du VIH, ce qui suggère que les effets physiologiques dus à la SCD pourraient atténuer la progression du VIH.

Global Disparities in Wilms Tumor.

BACKGROUND: Wilms tumor accounts for more than 90% of all malignant kidney neoplasms in children. Survival after diagnosis and treatment is excellent in most high-income countries. Low- and middle-income countries (LMICs) continue to struggle with Wilms tumor detection and treatment. The purpose of this study was to compare the global incidence and outcomes of Wilms tumor. MATERIAL AND METHODS: Wilms tumor incidence data from the World Health Organization (WHO), International Incidence of Childhood Cancer, Volume III, was analyzed according to world region and country socioeconomic status using descriptive statistics and independent-sample Kruskal-Wallis Test. A literature review was also performed to assess outcomes and identify common themes. RESULTS: Wilms tumor was most common in children aged 0-4 y (median incidence 15.1 [IQR 11.8-18.7] ASR/million). High-income countries reported significantly higher median incidence than middle-income countries (8.6 [7.4-9.3] versus 6.1 [4.9-8.7] ASR/million; P < 0.01), although low-income countries reported the highest median incidence overall (9.8 [6.2-16.4] ASR/million). Low-income countries had the fewest countries with registries (n = 6). Overall survival ranged from 70% to 97% in high-income countries, 61%-94% in upper-middle-income countries, 0%-85% in lower-middle-income countries, and 25%-53% in low-income countries. Delay in diagnosis, lack of available treatment, and inadequate follow up contributed to the large variations in outcomes. CONCLUSIONS: Reported Wilms tumor incidence is highest in low-income countries, and these are also the countries that have the lowest survival. Lack of significance may reflect incomplete and absent data reporting from lower income countries. Accurate and comprehensive registries are the first steps to appropriate resource allocation in order to improve outcomes for this highly curable childhood malignancy.

CNS Langerhans cell histiocytosis: Common hematopoietic origin for LCH-associated neurodegeneration and mass lesions.

BACKGROUND: Central nervous system Langerhans cell histiocytosis (CNS-LCH) brain involvement may include mass lesions and/or a neurodegenerative disease (LCH-ND) of unknown etiology. The goal of this study was to define the mechanisms of pathogenesis that drive CNS-LCH. METHODS: Cerebrospinal fluid (CSF) biomarkers including CSF proteins and extracellular BRAFV600E DNA were analyzed in CSF from patients with CNS-LCH lesions compared with patients with brain tumors and other neurodegenerative conditions. Additionally, the presence of BRAFV600E was tested in peripheral mononuclear blood cells (PBMCs) as well as brain biopsies from LCH-ND patients, and the response to BRAF-V600E inhibitor was evaluated in 4 patients with progressive disease. RESULTS: Osteopontin was the only consistently elevated CSF protein in patients with CNS-LCH compared with patients with other brain pathologies. BRAFV600E DNA was detected in CSF of only 2/20 (10%) cases, both with LCH-ND and active lesions outside the CNS. However, BRAFV600E+ PBMCs were detected with significantly higher frequency at all stages of therapy in LCH patients who developed LCH-ND. Brain biopsies of patients with LCH-ND demonstrated diffuse perivascular infiltration by BRAFV600E+ cells with monocyte phenotype (CD14+ CD33+ CD163+ P2RY12- ) and associated osteopontin expression. Three of 4 patients with LCH-ND treated with BRAF-V600E inhibitor experienced significant clinical and radiologic improvement. CONCLUSION: In LCH-ND patients, BRAFV600E+ cells in PBMCs and infiltrating myeloid/monocytic cells in the brain is consistent with LCH-ND as an active demyelinating process arising from a mutated hematopoietic precursor from which LCH lesion CD207+ cells are also derived. Therapy directed against myeloid precursors with activated MAPK signaling may be effective for LCH-ND. Cancer 2018;124:2607-20. © 2018 American Cancer Society.

Evaluation of maternal and perinatal characteristics on childhood lymphoma risk: A population-based case-control study.

BACKGROUND: Lymphoma is one of the most common pediatric malignancies; however, there are few well-established risk factors. Therefore, we investigated if maternal and perinatal characteristics influenced the risk of childhood lymphoma. PROCEDURE: Information on cases (n = 374) diagnosed with lymphoma and born in Texas for the period 1995-2011 was obtained from the Texas Cancer Registry. Birth certificate controls were randomly selected at a ratio of 10 controls per 1 case for the same period of 1995-2011. Unconditional logistic regression was used to generate unadjusted (OR) and adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the following histologic subtypes: Hodgkin (HL), Burkitt (BL), and non-BL non-HLs (non-BL NHLs). RESULTS: Overall, our findings indicate specific maternal and perinatal characteristics influence childhood lymphoma risk. Mexico-born mothers were more likely to have offspring who developed BL compared to mothers born in the United States (U.S.; aOR: 2.15; 95% CI: 1.06-4.36). Further, mothers who resided at time of delivery in a county on the U.S.-Mexico border were more likely to give birth to offspring who developed non-BL NHL (aOR: 1.72; 95% CI: 1.11-2.67) compared to mothers not living on the U.S.-Mexico border at time of infant birth. Last, infants born large-for-gestational-age experienced a twofold increase in BL risk (aOR: 2.00; 95% CI: 1.10-3.65). CONCLUSIONS: In this population-based assessment, we confirmed previously reported risk predictors of childhood lymphoma, including sex of infant, while highlighting novel risk factors that warrant assessment in future studies.

Mapping the Epidemiology of Kaposi Sarcoma and Non-Hodgkin Lymphoma Among Children in Sub-Saharan Africa: A Review.

Children with human immunodeficiency virus (HIV) have an increased risk of developing Kaposi Sarcoma (KS) and non-Hodgkin lymphoma (NHL) compared to HIV-negative children. We compiled currently published epidemiologic data on KS and NHL among children in sub-Saharan Africa (SSA). Among countries with available data, the median incidence of KS was 2.05/100,000 in the general pediatric population and 67.35/100,000 among HIV-infected children. The median incidence of NHL was 1.98/100,000 among the general pediatric population, while data on NHL incidence among HIV-infected children were lacking. Larger regional studies are needed to better address the dearth of epidemiologic information on pediatric KS and NHL in SSA.

Risk factors and prognostic significance of platelet count abnormalities in children with HIV infection on antiretroviral therapy.

OBJECTIVES: To establish the incidence, risk factors and correlation with survival of thrombocytopenia and thrombocytosis (T/T) among children with HIV infection (CWH). DESIGN: A retrospective nested case control study of patients 0-18 years in five Baylor International Pediatric AIDS Initiative (BIPAI) centers in sub-Sahara Africa, 2004-2014. METHODS: Clinical and laboratory variables including complete blood counts (CBC) were extracted from the BIPAI electronic medical record system. Incident cases of T/T were identified and frequency-matched on follow-up time with controls with normal platelets. We calculated the prevalence and incidence density of T/T and used conditional logistic regression to evaluate their association with selected clinical variables. We constructed Kaplan-Meier curves and a Cox proportional hazards model to evaluate the impact of T/T on survival. RESULTS: Two thousand, one hundred and nine children were sampled. The incidence density of thrombocytopenia was 1 per 57.9 (95% confidence interval [CI] 50.3-66.8) CWH-years. Thrombocytopenia was higher in children with WHO Stage III/IV, lower in children on zidovudine, and had no association with use of lamivudine or nevirapine, CD4 + suppression, age, and nutrition status. Thrombocytopenia was independently associated with 2.2-fold higher mortality (95% CI 1.62-3.08). The incidence density of thrombocytosis was 1 per 11.4 (95% CI 10.7-12.1) CWH-years. Thrombocytosis was associated with higher CD4 + cell count, younger age, and use of lamivudine or nevirapine, and did not impact survival. CONCLUSIONS: Platelet count is a clinically valuable biomarker of HIV clinical progression and mortality. Laboratory studies are necessary to elucidate the mechanisms of T/T.

Early repair of large infant ventricular septal defect despite respiratory syncytial virus-induced respiratory failure with postrepair chylous pericardial effusion requiring pleuropericardial window: a case report and review of the literature.

The surgical correction of congenital cardiac lesions that are complicated by intercurrent respiratory syncytial virus (RSV) pneumonitis has traditionally been deferred for at least 6 to 8 weeks. The presumption is that using cardiopulmonary bypass will increase the risk of postoperative pulmonary complications. We present an infant who developed acute respiratory failure related to RSV pneumonitis and required urgent mechanical ventilation. Cardiac evaluation revealed a large nonrestrictive ventricular septal defect (VSD), aortic arch hypoplasia, normally functioning bicuspid aortic valve, and hemodynamic instability associated with markedly increased pulmonary blood flow. Separation from mechanical ventilation was unsuccessful preoperatively. He underwent VSD repair with cardiopulmonary bypass less than 4 weeks after initial RSV infection. He was extubated successfully within 72 hours of VSD repair. Approximately 6 weeks postoperatively, he developed a circumferential chylous pericardial effusion of unclear etiology--an exceedingly rare complication of VSD repair in early infancy in a non-Down syndrome patient. The chylous effusion was initially managed unsuccessfully with Portogen/Monogen and a percutaneously placed pericardial drain. Two weeks later, he underwent creation of a pleuropericardial window with successful resolution of the chylous effusion. It is of interest to pediatricians to be able to correctly time the repair of congenital heart disease lesions after RSV infection to minimize post-bypass pulmonary complications and yet avoid morbidity from undue delays in repair. In addition, chylopericardium can occur in infants after VSD repair, and dietary modification and catheter drainage may not be adequate.

SARS-CoV-2-Associated Multisystem Inflammatory Syndrome in a Child in Uganda: A Paediatric Experience in a Resource-Limited Setting.

SARS-CoV-2-associated Multisystem Inflammatory Syndrome in children (MIS-C) has been described in developed settings that have reported a high burden of COVID-19 cases. However, to date, there are few published cases of MIS-C that have been described in the African region. MIS-C has high morbidity and even mortality without a prompt diagnosis. We report a case of a 9-year-old girl who presented with typical clinical features of MIS-C in Uganda but had a delay in diagnosis. This case report aims to raise awareness among health providers in similar settings to improve clinical suspicion of MIS-C, facilitate prompt diagnosis and treatment, and thus improve outcomes.

Risk factors and prognostic significance of anemia in children with HIV infection on antiretroviral therapy.

OBJECTIVES: To establish the incidence, risk factors and prognostic effect of anemia in children living with HIV (CLWH). DESIGN: Retrospective nested case-control study of patients 0-18 years in five centers in sub-Saharan Africa, 2004-2014. METHODS: Incident cases of anemia were identified from electronic records and matched with CLWH without anemia. We calculated the incidence density of anemia and used conditional logistic regression to evaluate its association with risk factors, stratified by severity and type of anemia. We used a Cox proportional hazards model to evaluate the impact of anemia on survival. RESULTS: Two thousand, one hundred and thirty-seven children were sampled. The incidence density of anemia was 1 per 6.6 CLWH-years. Anemia was moderate in 31.8% and severe in 17.3% of anemia cases, which had 10-year mortality hazards of 3.4 and 4.5, respectively. Microcytic anemia (36% cases) was associated with 2.3-fold hazard of 10-year mortality, and with malnutrition and CD4 + suppression. Normocytic anemia (50.5% cases) was associated with 2.6-fold hazards of 10-year mortality, and with more severe malnutrition, CD4 + suppression, and WHO stage, but inversely associated with lamivudine and nevirapine therapy. Macrocytic anemia (13.5% cases) was neither associated with higher 10-year mortality nor with severe malnutrition or CD4 + suppression but was associated with WHO stage II/III and negatively associated with lamivudine therapy. CONCLUSION: This large multicountry study of CLWH found a high incidence density of anemia. Higher severity, normocytic and microcytic types of anemia were independently associated with long-term mortality. Laboratory studies are needed to decipher the mechanisms of anemia and how it impacts mortality in CLWH.

Asymptomatic complete atrioventricular block in a 13-year-old girl.

Atrioventricular (AV) block is a delay or an interruption in the transmission of an impulse from atria to ventricles due to an anatomic or a functional impairment in the conduction system. Atrioventricular block may be congenital or acquired. Electrocardiographic screening of asymptomatic school-aged children (median, 12.4 years) in Japan found the prevalence of a third-degree AV block to be 2 per 100,000. We report a case of asymptomatic complete AV block of unknown etiology in a 13-year-old child who did not require pacemaker placement. The importance of recognizing an asymptomatic complete AV block in the pediatric population, the classification and controversies of pacemaker placement, and the complications of pacemaker placement are discussed.

Transient bone marrow hypoplasia preceding T-Cell acute lymphoblastic leukemia: a case report.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy and is characterised by hyperproliferation of malignant lymphocytes in the bone marrow. Rarely, ALL may be preceded by a period of pancytopenia and bone marrow hypoplasia which spontaneously recovers. This phenomenon, which has not before been described in T-cell ALL, is referred to as transient bone marrow hypoplasia. CASE PRESENTATION: A 5-year-old boy who presented with high-grade fever and generalised lymphadenopathy, was found to have pancytopenia on peripheral blood count and bone marrow hypoplasia. He was observed over a one-month period during which his bone marrow and peripheral blood counts recovered spontaneously. Symptoms recurred after 4 months and he was found to have blast infiltration of the bone marrow and diagnosed with T-cell ALL. CONCLUSION: Cases of transient bone marrow hypoplasia or overt aplastic anemia with spontaneous recovery and then followed by B-cell ALL or Acute Myeloid Leukemia have been described previously in the medical literature. This is the first case of transient bone marrow hypoplasia resulting into ALL of T-cell immunophenotype. While marrow hypoplasia preceding ALL remains poorly understood, it suggests an antecedent environmental insult to lymphoid progenitors or a germline abnormality that predisposes to lymphoid dysplasia. This may provide clues to the hitherto unknown pathophysiological process and etiological factors that precede the majority of childhood ALL cases. This case enlightens pediatricians about the existence of such rare cases so as to periodically follow up children with pancytopenia and/or bone marrow hypoplasia for prolonged periods even after apparent recovery.

Association of race and ethnicity with clinical phenotype, genetics, and survival in pediatric acute myeloid leukemia.

Black and Hispanic children with acute myeloid leukemia (AML) have worse outcomes compared with White children. AML is a heterogeneous disease with numerous genetic subtypes in which these disparities have not been specifically investigated. In this study, we used the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database to examine the association of race-ethnicity with leukemia cytogenetics, clinical features, and survival outcomes within major cytogenetic subgroups of pediatric AML. Compared with White non-Hispanic patients, t(8;21) AML was more prevalent among Black (odds ratio [OR], 2.22; 95% confidence interval [CI], 1.28-3.74) and Hispanic patients (OR, 1.74; 95% CI, 1.05-2.83). The poor prognosis KMT2A rearrangement t(6;11)(q27;q23) was more prevalent among Black patients (OR, 6.12; 95% CI, 1.81-21.59). Among those with KMT2Ar AML, Black race was associated with inferior event-free survival (EFS) (hazard ratio [HR], 2.31; 95% CI, 1.41-3.79) and overall survival (OS) (HR, 2.54; 1.43-4.51). Hispanic patients with KMT2Ar AML also had inferior EFS (HR, 2.20; 95% CI, 1.27-3.80) and OS (HR, 2.07; 95% CI, 1.09-3.93). Similarly, among patients with t(8;21) or inv(16) AML (ie, core-binding factor [CBF] AML), Black patients had inferior outcomes (EFS HR, 1.93; 95% CI, 1.14-3.28 and OS HR, 3.24; 95% CI, 1.60-6.57). This disparity was not detected among patients receiving gemtuzumab ozogamicin (GO). In conclusion, racial-ethnic disparities in survival outcomes among young people with AML are prominent and vary across cytogenetic subclasses. Future studies should explore the socioeconomic and biologic determinants of these disparities.

Association of Rituximab Use With Adverse Events in Children, Adolescents, and Young Adults.

Importance: Rituximab is among the most frequently used immunotherapies in pediatrics. Few studies have reported long-term adverse events associated with its use for children. Objective: To describe the use of rituximab and to assess whether its use is associated with short- or long-term adverse events, infections, or time to immune reconstitution in a diverse group of young people. Design, Setting, and Participants: This retrospective cohort study included 468 patients aged younger than 21 years who received rituximab for diverse indications between October 1, 2010, and December 31, 2017, at Texas Children's Hospital, a large pediatric referral hospital. Patterns of adverse events, infections, and immune recovery are described. Data analyses were conducted from December 2019 to June 2020. Exposure: One or more doses of rituximab. Main Outcomes and Measures: Adverse drug events (eg, anaphylaxis), incidence of mild and severe infections, and time to recovery of B lymphocyte subset counts and immunoglobulin levels. Survival models and logistic regression analyses and were used to identify associated risk factors of infectious and noninfectious adverse drug events. Results: We identified 468 patients receiving at least 1 dose of rituximab. The total follow-up time was 11 713 person-months. Of the 468 patients, 293 (62.6%) were female, the median (interquartile range) age at receipt of dose was 14.3 (9.9-16.8) years, and 209 (44.7%) were self-reported White Hispanic. Adverse events associated with rituximab infusion occurred in 72 patients (15.4%), and anaphylaxis occurred in 17 patients (3.6%). Long-term adverse events, such as prolonged neutropenia and leukoencephalopathy, were absent. Infections occurred in 224 patients (47.9%); 84 patients (17.9%) had severe infections, and 3 patients (0.6%) had lethal infections. Concurrent use of intravenous chemotherapy, treatment of systemic lupus erythematosus, neutropenia, and use of intravenous immunoglobulin were associated with increased risk of infection. Among 135 patients (28.8%) followed up to B cell count recovery, CD19+ or CD20+ cell numbers normalized in a median of 9.0 months (interquartile range, 5.9-14.4 months) following rituximab use; 48 of 95 patients (51%) evaluated beyond a year had low-for-age B cell counts. Recovery of CD27+ memory B cell number occurred in a median of 15.7 months (interquartile range, 6.0-22.7 months). Among patients with normal baseline values, low immunoglobulin G (IgG) levels developed in 67 of 289 patients (23.2%) and low IgM levels in 118 of 255 patients (40.8%); of these patients evaluated beyond 12 months from rituximab, 16 of 117 (13.7%) had persistently low IgG and 37 (33.9%) of 109 had persistently low IgM. Conclusions and Relevance: Rituximab is well tolerated among young people and is associated with few serious adverse events, but infections are common, corresponding to a prolonged period of B cell count recovery often lasting for longer than a year. Further examination of strategies to prevent infections following rituximab should be pursued.