Minimal Residual Disease in Acute Lymphoblastic Leukemia: Current Practice and Future Directions.

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer and advances in its clinical and laboratory biology have grown exponentially over the last few decades. Treatment outcome has improved steadily with over 90% of patients surviving 5 years from initial diagnosis. This success can be attributed in part to the development of a risk stratification approach to identify those subsets of patients with an outstanding outcome that might qualify for a reduction in therapy associated with fewer short and long term side effects. Likewise, recognition of patients with an inferior prognosis allows for augmentation of therapy, which has been shown to improve outcome. Among the clinical and biological variables known to impact prognosis, the kinetics of the reduction in tumor burden during initial therapy has emerged as the most important prognostic variable. Specifically, various methods have been used to detect minimal residual disease (MRD) with flow cytometric and molecular detection of antigen receptor gene rearrangements being the most common. However, many questions remain as to the optimal timing of these assays, their sensitivity, integration with other variables and role in treatment allocation of various ALL subgroups. Importantly, the emergence of next generation sequencing assays is likely to broaden the use of these assays to track disease evolution. This review will discuss the biological basis for utilizing MRD in risk assessment, the technical approaches and limitations of MRD detection and its emerging applications.

Catheter-directed Thrombolysis for Neonatal IVC and Bilateral Renal Vein Thrombosis: A Case Report.

Renal vein thrombosis is the most common non-catheter-associated venous thromboembolism event in neonates, accounting for up to 20% of cases. Although mortality rates are lower than a variety of other forms of pediatric thrombosis, renal vein thrombi are associated with significant short-term and long-term sequelae. This report presents the case of a full-term neonate presenting with bilateral renal vein thrombosis with inferior vena cava involvement treated with catheter-directed thrombolysis. This case report intends to highlight the value of a multidisciplinary approach to pediatric venous thromboembolism and to outline relevant procedural details and current laboratory and imaging monitoring of catheter-directed thrombolysis.

Immunotherapy in Pediatric B-Cell Acute Lymphoblastic Leukemia: Advances and Ongoing Challenges.

Leukemia, most commonly B-cell acute lymphoblastic leukemia (B-ALL), accounts for about 30% of childhood cancer diagnoses. While there have been dramatic improvements in childhood ALL outcomes, certain subgroups-particularly those who relapse-fare poorly. In addition, cure is associated with significant short- and long-term side effects. Given these challenges, there is great interest in novel, targeted approaches to therapy. A number of new immunotherapeutic agents have proven to be efficacious in relapsed or refractory disease and are now being investigated in frontline treatment regimens. Blinatumomab (a bispecific T-cell engager that targets cluster of differentiation [CD]-19) and inotuzumab ozogamicin (a humanized antibody-drug conjugate to CD22) have shown the most promise. Chimeric antigen receptor T (CAR-T) cells, a form of adoptive immunotherapy, rely on the transfer of genetically modified effector T cells that have the potential to persist in vivo for years, providing ongoing long-term disease control. In this article, we discuss the clinical biology and treatment of B-ALL with an emphasis on the role of immunotherapy in overcoming the challenges of conventional cytotoxic therapy. As immunotherapy continues to move into the frontline of pediatric B-ALL therapy, we also discuss strategies to address unique side effects associated with these agents and efforts to overcome mechanisms of resistance to immunotherapy.

Catastrophic Delayed Hemolytic Transfusion Reaction in a Patient With Sickle Cell Disease Without Alloantibodies: Case Report and Review of Literature.

While packed red blood cell (PRBC) transfusion therapy is a mainstay in the treatment of certain patients with sickle cell disease (SCD) and the standard of care for preoperative management, there are associated risks. Delayed hemolytic transfusion reaction (DHTR) is a risk of PRBC transfusion occurring 2 to 20 days from transfusion and typically presents with severe pain characteristic of vaso-occlusive crisis, fever, and hemolytic anemia. DHTRs are uncommon, occurring in only 4% to 11% of transfused patients with SCD, but may be catastrophic in nature with progression to multiorgan failure within hours. Here, we describe a case of a 20-year-old female with sickle cell SS disease who developed a severe DHTR 5 days following an elective preoperative PRBC transfusion, and rapidly progressed to multiorgan failure and death. This is the first reported case of a catastrophic DHTR in a patient with SCD without any detectable known or new alloantibodies.

Sirolimus as an Effective Agent in the Treatment of Immune Thrombocytopenia (ITP) and Evans Syndrome (ES): A Single Institution's Experience.

BACKGROUND: Autoimmune cytopenias are characterized by immune-mediated destruction of hematopoietic cell lines with immune thrombocytopenia (ITP) affecting platelets and Evans syndrome (ES) affecting platelets and red blood cells. For patients with persistent disease, limited options for effective and well-tolerated therapies exist. OBJECTIVES: Our aim is to describe our institution's experience with sirolimus as therapy for pediatric patients with persistent ITP and ES. DESIGN/METHOD: A retrospective analysis was performed in patients with persistent ITP and ES treated with sirolimus. Responses were categorized as complete response (CR), partial response, modest response, or no response. RESULTS: Of the 17 patients treated, 12 had ITP and 5 had ES. Seventy-three percent of ITP patients achieved a CR, 78% of them by 3 months. Only 2 patients did not achieve a durable response. Eighty percent of ES patients had a response, with 50% of them achieving CR and the other 50% an asymptomatic partial response. One patient with ES achieved modest response, but discontinued therapy due to an adverse effect. Of the patients that achieved CR, 90% remain off all therapy for a median of 2 years. CONCLUSIONS: Our data suggest that sirolimus is a safe and effective steroid-sparing agent in the treatment of persistent ITP and ES.