A QA Program for MRD Testing Demonstrates That Systematic Education Can Reduce Discordance Among Experienced Interpreters.

BACKGROUND: Minimal residual disease (MRD) in B lymphoblastic leukemia (B-ALL) by flow cytometry is an established prognostic factor used to adjust treatment in most pediatric therapeutic protocols. MRD in B-ALL has been standardized by the Children's Oncology Group (COG) in North America, but not routine clinical labs. The Foundation for National Institutes of Health sought to harmonize MRD measurement among COG, oncology groups, academic, community and government, laboratories. METHODS: Listmode data from post-induction marrows were distributed from a reference lab to seven different clinical FCM labs with variable experience in B-ALL MRD. Labs were provided with the COG protocol. Files from 15 cases were distributed to the seven labs. Educational sessions were implemented, and 10 more listmode file cases analyzed. RESULTS: Among 105 initial challenges, the overall discordance rate was 26%. In the final round, performance improved considerably; out of 70 challenges, there were five false positives and one false negative (9% discordance), and no quantitative discordance. Four of six deviations occurred in a single lab. Three samples with hematogones were still misclassified as MRD. CONCLUSIONS: Despite the provision of the COG standardized analysis protocol, even experienced laboratories require an educational component for B-ALL MRD analysis by FCM. Recognition of hematogones remains challenging for some labs when using the COG protocol. The results from this study suggest that dissemination of MRD testing to other North American laboratories as part of routine clinical management of B-ALL is possible but requires additional educational components to complement standardized methodology. © 2017 International Clinical Cytometry Society.

B-ALL minimal residual disease flow cytometry: an application of a novel method for optimization of a single-tube model.

OBJECTIVES: Optimizing a clinical flow cytometry panel can be a subjective process dependent on experience. We develop a quantitative method to make this process more rigorous and apply it to B lymphoblastic leukemia/lymphoma (B-ALL) minimal residual disease (MRD) testing. METHODS: We retrospectively analyzed our existing three-tube, seven-color B-ALL MRD panel and used our novel method to develop an optimized one-tube, eight-color panel, which was tested prospectively. RESULTS: The optimized one-tube, eight-color panel resulted in greater efficiency of time and resources with no loss in diagnostic power. CONCLUSIONS: Constructing a flow cytometry panel using a rigorous, objective, quantitative method permits optimization and avoids problems of interdependence and redundancy in a large, multiantigen panel.

Subcutaneous panniculitic T-cell lymphoma in a cardiac allograft recipient.

BACKGROUND: Post-transplant lymphoproliferative disorder (PTLD) is the third leading cause of death in heart transplant patients beyond the immediate peri-operative period (Ouseph R, Denny DM, Erbeck KM. J Am Soc Echocardiogr 1998; 11: 758; Armitage JM, Kormos RL, Stuart RS, et al. J Heart Lung Transplant 1991; 10: 877; Swinnen LJ, Mullen M, Carr TJ, et al. Blood 1995; 86: 3333; Ying AJ, Myerowitz D, Marsh WL. Ann Thorac Surg 1997; 64: 1822). The majority of PTLD cases are of B-cell origin whereas T-cell neoplasms have been reported as rare, aggressive, and late complications of solid-organ transplantation (Fatio R, Sutsch G, Mayer K, et al. Transplant Proc 1998; 30: 1118). CASE REPORT: A 50-year-old cardiac allograft heart transplant patient presented with subcutaneous nodules involving his trunk and extremities. RESULTS: Light microscopy revealed features characteristic of subcutaneous panniculitic-like T-cell lymphoma. Immunohistochemical analysis showed expression for CD45RO, TIA-1, and focal CD3 positivity by tumor cells. Flow cytometry performed on a subsequent subcutaneous nodule demonstrated an abnormal T-cell population with expression of CD3, CD8, CD56, and T-cell receptor alpha-beta, and no expression of CD4. T-cell gene rearrangement studies revealed a clonal population of cells with a bi-allelic gene rearrangement. CONCLUSION: We report a case of an unusual subtype of PTLD in a cardiac allograft recipient.