Critical Pitfalls in the Flowcytometric Analysis of Mast Cells in Patients with Systemic Mastocytosis

Description of the files: A set of sample files of a case with systemic mastocytosis showing the co-existence of aberrant CD25/CD2/CD30-positive mast cells with non-aberrant CD25/CD2/CD30-negative mast cells. Background information: Systemic mastocytosis (SM) is a neoplastic disorder marked by abnormal mast cell (MC) activation and proliferation. Accurate diagnosis frequently involves flow cytometry to assess aberrant CD25, CD2, and CD30 expression on MCs. However, this analysis faces several challenges, including low MC numbers, the absence of highly specific antigens, and strong autofluorescence, which can lead to potential interferences and misinterpretations. Notably, no studies have yet investigated the potential interferences with MC gating, further complicating the diagnostic process. We performed a study to map the potential interferences in the flowcytometric analysis of MCs to fill the gap in the literature and provide more guidance for other medical centers on how to perform the analysis. Research was performed by the lab of Laboratory Medicine in the University Medical Center of Groningen (UMCG). For this retrospective study, data has been gathered over the time span of 2009 until 2024. For this research, no funds were received from any external parties.