Assessment of CD38brightHLA-DR+ T cells using a rapid flow cytometry-based assay to aid in the diagnosis of hemophagocytic lymphohistiocytosis and immune regulatory disorders in adult subjects

Rapid and accurate diagnosis of patients suspected of suffering from hyperinflammatory conditions such as hemophagocytic lymphohistiocytosis (HLH) is a critical aspect of timely management for such disorders. Soluble IL-2Rα (sIL-2Rα) and plasma ferritin constitute the mainstay of frontline laboratory investigations performed to establish a clinical diagnosis for these patients. However, there is a paucity of clinical laboratories that perform the sIL-2Rα measurement as a stat test which can delay the diagnosis and management of these patients. Consequently, rapid flow cytometry-based tests that measure T cell activation are currently being evaluated. Previous studies have examined the utility of flow-cytometry based testing in pediatric subjects with HLH and immune dysregulation disorders. In this report, we assessed the utility of our flow-cytometry based test in adult patients suspected of HLH and discuss its performance in relation to what has been reported previously in the literature for pediatric patients.