Immunotherapy-resistant acute lymphoblastic leukemia cells exhibit reduced CD19 and CD22 expression and BTK pathway dependency.

While therapies targeting CD19 by antibodies, chimeric antigen receptor T cells (CAR-T), and T cell engagers have improved the response rates in B cell malignancies, the emergence of resistant cell populations with low CD19 expression can lead to relapsed disease. We developed an in vitro model of adaptive resistance facilitated by chronic exposure of leukemia cells to a CD19 immunotoxin. Single-cell RNA-Seq (scRNA-Seq) showed an increase in transcriptionally distinct CD19lo populations among resistant cells. Mass cytometry demonstrated that CD22 was also decreased in these CD19lo-resistant cells. An assay for transposase-accessible chromatin with sequencing (ATAC-Seq) showed decreased chromatin accessibility at promoters of both CD19 and CD22 in the resistant cell populations. Combined loss of both CD19 and CD22 antigens was validated in samples from pediatric and young adult patients with B cell acute lymphoblastic leukemia (B-ALL) that relapsed after CD19 CAR-T-targeted therapy. Functionally, resistant cells were characterized by slower growth and lower basal levels of MEK activation. CD19lo resistant cells exhibited preserved B cell receptor signaling and were more sensitive to both Bruton's tyrosine kinase (BTK) and MEK inhibition. These data demonstrate that resistance to CD19 immunotherapies can result in decreased expression of both CD19 and CD22 and can result in dependency on BTK pathways.

Peritoneal and Pleural Drains in Pediatric Hematopoietic Cell Transplant Recipients with Veno-Occlusive Disease are Safe and Do Not Adversely Impact Clinical Outcomes.

There is a lack of data on the safety and efficacy of peritoneal drain (PD) and chest tube (CT) in the management of effusions in stem cell transplant recipients with veno-occlusive disease (VOD). In this retrospective pediatric study, clinical outcomes and health resource utilization (HRU) were compared in 32 patients with VOD who had a PD (PD+) post-HCT versus 27 patients who did not (PD-). Nine patients also had a CT (7 PD+ and 2 PD-). PD + patients were more likely than PD-patients to have received myeloablative conditioning (100% vs. 85.2%; p = 0.04) and have severe or very severe VOD (100% vs. 56% p < 0.01). Mechanical obstruction (38%) and hypotension (38%) were common complications, and 13% developed peritonitis. While the frequencies of cardiac dysfunction and acute kidney injury were comparable between both groups, respiratory support and its median duration were higher in PD + patients. The hospital and intensive care unit length of stay, albumin use, and the duration of defibrotide and albumin therapy was significantly longer in PD + patients. At a median follow-up of 1.04 years (range:0.03-14.6), the 2-year overall survival was similar in both groups (53.8% vs. 51.5%; p = 0.73). Although PD use was similar between 1995 and 2007 vs. 2008-2021; (47% vs. 58%; p = 0.65), day+100 mortality was improved in recent years (53.3% vs. 17.8%; p = 0.01), coinciding with the use of defibrotide (0% vs. 84%; p < 0.01). PD in pediatric patients with VOD post-HCT, although associated with increased HRU, was safe when clinically indicated and did not adversely impact clinical outcomes.

CD34 Stem Cell Boost in Pediatric Allogeneic Stem Cell Transplant Recipients: A Case Series and Review of Literature.

Patients with poor graft function (PGF) or declining donor chimerism (DC) post allogeneic hematopoietic cell transplantation (HCT) may benefit from a CD34-selected stem cell boost (SCB). We retrospectively studied outcomes of fourteen pediatric patients (PGF: 12 and declining DC: 2), with a median age of 12.8 (range 0.08-20.6) years at HCT, who received a SCB. Primary and secondary endpoints included resolution of PGF or improvement in DC (≥ 15% increase), overall survival (OS) and transplant-related mortality (TRM), respectively. The median CD34 dose infused was 7.47 × 106/kg (range 3.51 × 106-3.39 × 107/kg). Among patients with PGF who survived ≥ 3 months post-SCB (n = 8), we observed a non-significant decrease in the cumulative median number of red cell transfusions, platelet transfusions, and GCSF but not intravenous immunoglobulin doses in the 3 months before and after SCB. Overall response rate (ORR) was 50%, with 29% complete and 21% partial responses. ORR was better in recipients who received lymphodepletion (LD) pre-SCB versus none (75% versus 40%; p = 0.56). The incidence of acute and chronic graft-versus-host-disease was 7% and 14%, respectively. The 1-year OS was 50% (95% CI 23-72%) and TRM was 29% (95% CI 8-58%). SCB was effective in half of our cohort with possible benefit of LD pre-SCB.

Acute kidney injury in pediatric hematopoietic cell transplantation: critical appraisal and consensus.

Hematopoietic cell transplantation (HCT) is a common therapy for the treatment of neoplastic and metabolic disorders, hematological diseases, and fatal immunological deficiencies. HCT can be subcategorized as autologous or allogeneic, with each modality being associated with their own benefits, risks, and post-transplant complications. One of the most common complications includes acute kidney injury (AKI). However, diagnosing HCT patients with AKI early on remains quite difficult. Therefore, this evidence-based guideline, compiled by the Pediatric Continuous Renal Replacement Therapy (PCRRT) working group, presents the various factors that contribute to AKI and recommendations regarding optimization of therapy with minimal complications in HCT patients.

Quality Improvement in Hematopoietic Stem Cell Transplant and Cellular Therapy: Using the Model for Improvement to impact Outcomes.

Quality improvement and quality assurance form a complementary and independent relationship. Quality assurance measures compliance against industry standards using audits, whereas quality improvement is a continuous process focused on processes and systems that can improve care. The Model for Improvement is a robust quality improvement tool that transplant and cellular therapy teams can use to redesign healthcare processes. The Model for Improvement uses several components addressed in sequence to organize and critically evaluate improvement activities. Unlike other health sciences clinical research, quality improvement projects, and research are based on dynamic hypotheses that develop into observable, serial tests of change with continuous collection and feedback of performance data to stakeholders.

Allogeneic Hematopoietic Cell Transplant for Systemic Juvenile Idiopathic Arthritis and Macrophage Activation Syndrome.

Systemic juvenile idiopathic arthritis (sJIA) is characterized by arthritis, fever, rash, lymphadenopathy, hepatosplenomegaly, and serositis. Macrophage activation syndrome is the most feared complication of sJIA with a high risk of mortality. We report a 16-year-old female diagnosed with refractory systemic juvenile idiopathic arthritis (sJIA) complicated by recurrent macrophage activation syndrome (MAS), severe joint disease, and lung involvement requiring prolonged immunosuppressive therapy. She received a matched unrelated allogeneic hematopoietic cell transplant (Allo-HCT) using a reduced-intensity conditioning regimen and is now, 3 years after the transplant, with complete resolution of sJIA symptoms, off immunosuppressants, and with significant improvement in the quality of life.

Use of belatacept as alternative graft vs host disease prophylaxis in pediatric allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Immunosuppressive prophylaxis is usually given to decrease the development of acute graft versus host disease (GvHD) after allogeneic hematopoietic stem cell transplantation (HSCT). Belatacept is a Cytotoxic T-lymphocyte-associated protein 4, blocking agent, an immunosuppressive agent used for organ rejection prevention in adult renal transplant recipients. METHODS: We describe two children in whom belatacept was successfully used for GvHD prophylaxis. Case 1 was noncompliant with prior immunosuppressive therapy for aplastic anemia, and Case 2 developed severe thrombotic microangiopathy (TMA) precluding the use of calcineurin inhibitors (CNI) or mTOR inhibitors. RESULTS AND CONCLUSION: Belatacept was found to be a safe alternative in preventing GvHD in 2 patients in whom traditional prophylactic therapies were not possible to use.

The RUNX1/IL-34/CSF-1R axis is an autocrinally regulated modulator of resistance to BRAF-V600E inhibition in melanoma.

Resistance to current therapies still impacts a significant number of melanoma patients and can be regulated by epigenetic alterations. Analysis of global cytosine methylation in a cohort of primary melanomas revealed a pattern of early demethylation associated with overexpression of oncogenic transcripts. Loss of methylation and associated overexpression of the CSF 1 receptor (CSF1R) was seen in a majority of tumors and was driven by an alternative, endogenous viral promoter in a subset of samples. CSF1R was particularly elevated in melanomas with BRAF and other MAPK activating mutations. Furthermore, rebound ERK activation after BRAF inhibition was associated with RUNX1-mediated further upregulation of CSF-1R and its ligand IL-34. Importantly, increased CSF-1R and IL-34 overexpression were detected in an independent cohort of resistant melanomas. Inhibition of CSF-1R kinase or decreased CSF-1R expression by RNAi reduced 3-D growth and invasiveness of melanoma cells. Coinhibition of CSF-1R and BRAF resulted in synergistic efficacy in vivo. To our knowledge, our data unveil a previously unknown role for the autocrine-regulated CSF-1R in BRAF V600E resistance and provide a preclinical rationale for targeting this pathway in melanoma.

Allogeneic hematopoietic stem cell transplantation is associated with cure and durable remission of late-onset primary isolated central nervous system hemophagocytic lymphohistiocytosis.

Primary isolated CNS presentation of HLH is exceedingly rare and typically associated with significant morbidity and mortality. We describe an adolescent patient with late-onset, primary isolated CNS HLH and a compound heterozygous PRF1 mutation (c50delT (p.L17 fs); c.1229G>C (p.R410P)), not previously reported with this phenotype. He was successfully treated with allogeneic HSCT following a reduced-intensity conditioning regimen, despite a high pre-HSCT comorbidity index. Two years after transplant, he is alive and in disease remission. While patients with systemic HLH and active CNS disease have relatively poorer outcomes, a high index of suspicion may aid with early diagnosis of primary isolated CNS HLH; prompt treatment with HSCT may be associated with improved cure and durable remission of this rare disease.

5-Azacitidine Monotherapy Followed by Related Haploidentical Hematopoietic Stem Cell Transplantation Achieves Durable Remission in a Pediatric Patient With Acute Undifferentiated Leukemia Refractory to High-Dose Chemotherapy.

Patients with acute leukemias of undifferentiated lineage (AUL) generally have guarded prognosis. Here, we describe the first reported pediatric patient with AUL refractory to high-dose chemotherapy who achieved clinical remission with ALL maintenance therapy and 5-azacitidine. His induction remission was followed by consolidation with reduced toxicity haploidentical hematopoietic stem cell transplant (HSCT). At 9 months post-HSCT, the patient is alive and in remission. This combination therapy of remission induction with ALL maintenance therapy and 5-azacitidine and consolidation with reduced toxicity haploidentical HSCT is novel and promising for patients who lack conventional donors and are not candidates for myeloablative therapy.

Attitudes and perceptions of the HPV vaccine in Caribbean and African-American adolescent girls and their parents.

OBJECTIVE: To describe attitudes and perceptions toward acceptability of human papilloma virus (HPV) vaccination among inner city Caribbean (CA) and African American (AA) adolescents and their parents, and discuss correlates that may be associated with these factors. DESIGN: Questionnaire survey. SETTING: An adolescent medicine clinic. PARTICIPANTS: A convenience sample was recruited of 175 adolescent girls aged 13 to 19 years and 74 parents attending adolescent clinic. INTERVENTION: Participants completed an anonymous confidential 10-minute questionnaire. MAIN OUTCOME MEASURES: Data on knowledge about HPV, cervical cancer (CC), attitudes and acceptance of the HPV vaccine. RESULTS: Responses of 175 adolescent girls and 74 parents were analyzed. Overall, 48.9% of the teens were sexually active (SA) and had a 2.2-fold greater odds (OR = 2.21; 95% CI = 1.13-4.36) of being interested in HPV vaccination versus girls who were not SA. While only 55.8% of girls knew what HPV is, this knowledge was significantly associated with knowing that most CC is caused by HPV (P < 0.001) and with interest in receiving HPV vaccination (P < 0.001). Less than half (44.5%) of adolescent girls were interested in receiving the HPV vaccine and only 37.5% of parents. There were no significant influences in parental acceptance of the vaccine with regard to age, ethnicity and educational level, insurance, and living situation.The majority of parents wanted the vaccine for its role in preventing CC. CONCLUSIONS: Although controversy surrounds HPV vaccine in regard to its supposed role in promoting SA, only a minority of our parents showed concern for that association. The level of acceptance of the HPV vaccine was overall lower than what has been reported among other racial/ethnic populations. Knowledge about HPV and its association with CC were significantly associated with interest in getting the HPV vaccine and both parents and teens seem to accept the HPV vaccine more for its role in CC prevention.