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.

Durable immunity to EBV after rituximab and third-party LMP-specific T cells: a Children's Oncology Group study.

ABSTRACT: Posttransplant lymphoproliferative disease (PTLD) in pediatric solid organ transplant (SOT) recipients is characterized by uncontrolled proliferation of Epstein-Barr virus-infected (EBV+) B cells due to decreased immune function. This study evaluated the feasibility, safety, clinical and immunobiological outcomes in pediatric SOT recipients with PTLD treated with rituximab and third-party latent membrane protein-specific T cells (LMP-TCs). Newly diagnosed (ND) patients without complete response to rituximab and all patients with relapsed/refractory (R/R) disease received LMP-TCs. Suitable LMP-TC products were available for all eligible subjects. Thirteen of 15 patients who received LMP-TCs were treated within the prescribed 14-day time frame. LMP-TC therapy was generally well tolerated. Notable adverse events included 3 episodes of rejection in cardiac transplant recipients during LMP-TC therapy attributed to subtherapeutic immunosuppression and 1 episode of grade 3 cytokine release syndrome. Clinical outcomes were associated with disease severity. Overall response rate (ORR) after LMP-TC cycle 1 was 70% (7/10) for the ND cohort and 20% (1/5) for the R/R cohort. For all cohorts combined, the best ORR for LMP-TC cycles 1 and 2 was 53% and the 2-year overall survival was 70.7%. vßT-cell receptor sequencing showed persistence of adoptively transferred third-party LMP-TCs for up to 8 months in the ND cohort. This study establishes the feasibility of administering novel T-cell therapies in a cooperative group clinical trial and demonstrates the potential for positive outcomes without chemotherapy for ND patients with PTLD. This trial was registered at www.clinicaltrials.gov as #NCT02900976 and at the Children's Oncology Group as ANHL1522.

Pediatric cutaneous T-cell neoplasm and mimics with gamma-delta expression: Not always aggressive.

Pediatric cutaneous T-cell lymphoma with γδ immunophenotype is extremely rare. Only a few cases of γδ T-cell neoplasm have been reported in the literature, and therefore little is known whether γδ T-cell neoplasms in children are distinct from their adult counterparts with respect to the clinicopathological presentation, behavior, and prognosis. In this study, we demonstrate three unique pediatric cutaneous T-cell neoplasm and mimics with increased γδ T cells. All cases showed an indolent clinical course.

Implementation of a tier system for IVIG indications to address IVIG shortage at a tertiary care pediatric medical center.

BACKGROUND: Drug shortages are a common issue that healthcare systems face and can result in adverse health outcomes for patients requiring inferior alternate treatment. The United States recently experienced a national drug shortage of intravenous immunoglobulin (IVIG). Several reported strategies to address the IVIG and other drug shortages have been proposed; however, there is a lack of evidence-based methods for protocol development and implementation. OBJECTIVE: To evaluate the efficacy of introducing a multidisciplinary task force and tier system of indications and to minimize adverse effects during a shortage of IVIG. METHODS: Faculty members across disciplines with expertise in IVIG use were invited to participate in a task force to address the shortage and ensure adequate supply for emergent indications. A tier system of IVIG indications was established according to the severity of diagnosis, urgency of indication, and quality of supporting evidence. Based on inventory, indications in selected tiers were auto-approved. Orders that could not be automatically approved were escalated for task force review. RESULTS: Overall, there were 342 distinct requests for IVIG during the study period (August 1, 2019 to December 31, 2019). All Tier 1 indications were approved. Of all requests, only 2.6% (9) of requests were denied, none of which resulted in adverse effects based on retrospective chart review. Seven patients who regularly receive IVIG had possible adverse effects due to dose reduction or spacing of treatment; however, each complication was multifactorial and not attributed to the shortage or tier system implementation alone. CONCLUSION: Implementation of a multidisciplinary task force and tier system to appropriately triage high-priority indications for limited pharmaceutical agents should be considered in health institutions faced with a drug shortage.