Pathophysiology of IEC-EC and the Lymphoproliferative Differential

In this segment the panelists, Dr. Samir Parekh and Dr. Saurabh Mehandru, both of Mount Sinai in New York, examine what drives immune effector cell-associated enteritis/colitis (IEC-EC) after chimeric antigen receptor (CAR) T-cell therapy and how to separate it from a malignant process. Dr. Mehandru describes two patterns. In the earlier presentation, CAR T cells infiltrate and can persist in the intestine, where they may exert direct toxic effects, often in patients with other side effects including neurologic ones and with expansion of CAR T cells in circulation. In the later presentation, patients in sustained myeloma remission but with prolonged loss of the B-cell compartment develop protracted diarrhea, abdominal pain, and weight loss, with dysregulation across multiple intestinal cell types that suggests a problem accumulating over time. Dr. Parekh notes that finding CAR T cells in tissue is not required to make the diagnosis, and cautions that clonal T cells alone do not indicate a lymphoproliferative disease, since T cells normally become oligoclonal in response to antigen. He describes the features that do point to T-cell lymphoma, including mass-like collections, lymphadenopathy, effacement of normal gastrointestinal tissue by clonal disease, and a characteristic mutation repertoire identifiable by next-generation sequencing, and stresses that the distinction matters because the two conditions are treated very differently.

This Insights Video was supported by Janssen Pharmaceutical. Content independently developed and published by OncLive.