Diagnosis and treatment of pediatric myelodysplastic syndromes: A survey of the North American Pediatric Aplastic Anemia Consortium

BACKGROUND

Myelodysplastic syndromes (MDS) represent a group of clonal hematopoietic stem cell disorders that commonly progress to acute myeloid leukemia (AML). The diagnostics, prognostics, and treatment of adult MDS are established but do not directly translate to children and adolescents. Pediatric MDS is a rare disease, characterized by unique cytogenetics and histology compared with adult MDS, and often arises secondary to germline predisposition or cytotoxic exposures. Our objective was to highlight aspects of diagnosis/management that would benefit from further systematic review toward the development of clinical practice guidelines for pediatric MDS.

PROCEDURE

The North American Pediatric Aplastic Anemia Consortium (NAPAAC) is composed of collaborative institutions with a strong interest in pediatric bone marrow failure syndromes and hematologic malignancies. The NAPAAC MDS working group developed a national survey distributed to 35 NAPAAC institutions to assess data on (1) clinical presentation of pediatric MDS, (2) diagnostic evaluation, (3) criteria for diagnosis, (4) supportive care and treatment decisions, and (5) role of hematopoietic stem cell transplantation (HSCT).

RESULTS

Twenty-eight of 35 institutions returned the survey. Most centers agreed on a common diagnostic workup, though there was considerable variation regarding the criteria for diagnosis. Although there was consensus on supportive care, treatment strategies, including the role of cytoreduction and HSCT, varied across centers surveyed.

CONCLUSIONS

There is lack of national consensus on diagnosis and treatment of pediatric MDS. This survey identified key aspects of MDS management that will warrant systematic review toward the goal of developing national clinical practice guidelines for pediatric MDS.

Strategies to Improve Pediatric Cancer Pathology and Tissue Handling for Clinical Care and Research in Low-Resource Settings

PURPOSE

Evidence-based pediatric cancer control is dependent on accurate, timely cancer diagnosis, as well as maintenance of tissue integrity and annotation for clinical diagnosis and clinical/translational research. Scarcity of cancer pathology infrastructure and the delinkage of clinical pathology and research workflows in low- and middle-income countries thwarts real-time, high-resolution diagnosis, risk stratification, and maintenance of tissue integrity for future research. This renders the application of evidence-based treatments and conduct of translational research and clinical trials, particularly across multiple centers in low- and middle-income countries, impractical. We present the innovative approach and impact of a Texas Children’s Global HOPE model designed to overcome these systemic obstacles in a sub-Saharan Africa setting.

METHODS

We designed a pathology algorithm at Mulago Hospital Complex in Uganda with the following goals: integrate clinical and research workflows, ensure safe and optimal tissue biopsies, and maintain tissue integrity for clinical and research assays. We introduced new assays built on locally available technology platforms for anatomic pathology and immunophenotyping.

RESULTS

The novel workflow and assays enabled consistent real-time hematoxylin and eosin microscopy, immunohistochemistry, and multiparametric flow cytometry. The proportion of cancer diagnoses based on tissue pathology increased from 67.5% to 100%. Streamlined pathology processes improved the timeliness of commencement of treatment from 4 to 6 weeks to 24 hours in the case of acute leukemias. The refined diagnosis process has enabled implementation of risk-adapted treatment regimens. Overall, these strategies contributed to improved overall survival from 30% to 85% at 1 month, and have revealed hitherto unrecognized clinical patterns of pediatric cancers in sub-Saharan Africa.

CONCLUSION

Accurate real-time pathology for pediatric cancers improves survival. Improvements should aim at enhancing the capabilities of existing in-country platforms and skilled personnel. Future efforts will focus on scaling up these practices to other sites and integrating molecular diagnostics that reduce overall cost and improve diagnostic accuracy or risk stratification.

Hemostatic/Fibrinolytic Protein Changes in C3H/HeN Mice Infected with Rickettsia conorii

Changes in plasma hemostatic and fibrinolytic proteins were determined during courses of a murine model of fatal and non-fatal Rocky Mountain spotted fever. C3H/HeN mice were infected with Rickettsia conorii and coagulation and histopathologic studies were performed at prescribed periods of time. A significant decrease in plasma factor VIII activity and rise in plasma factor V procoagulant activity correlated with a fatal infection. Factor VII levels were unchanged; factor XI levels dropped early in the course in the lethally infected animals, but returned to normal. Factor XII, high molecular weight kininogen, and prekallikrein levels were unchanged by the sublethal infection. Prekallikrein levels fell during the lethal infection. Antithrombin concentrations were decreased significantly in all animals, but plasma plasminogen levels did not change in either group of animals. Nonocclusive thrombi were microscopically observed rarely and only in animals surviving a sublethal infection. A fall in tissue plasminogen activator activity and a rise in plasminogen activator inhibitor activity highly correlated with a lethal outcome. Lethal infection with R. conorii is associated with primary endothelial cell injury resulting in decreased tissue plasminogen activator and increased plasminogen activator inhibitor.