When CAR T Cells Linger in the Gut

Persistent CAR T cells and widespread immune disruption may help explain a rare form of severe intestinal inflammation after BCMA-directed therapy

Category	Detail
Condition	CAR T-associated enterocolitis (CAR-TEC) after BCMA-directed CAR T-cell therapy
Key Mechanisms	Intestinal inflammation involving T cells, myeloid cells, stromal cells, and epithelium; findings included cytotoxic and inflammatory CAR T cells and activation of interferon and JAK–STAT signaling. Some cases lacked detectable mucosal CAR T-cell infiltration.
Target Population	Patients with multiple myeloma who developed enterocolitis after BCMA-directed CAR T-cell therapy
Care Setting	Single-cell and tissue-based analyses of intestinal samples from patients with CAR-TEC

CAR-TEC was associated with inflammatory changes across multiple intestinal cell types, not only B-cell and plasma-cell depletion.
Some patients without enterocolitis had similarly profound B-cell and plasma-cell depletion.
CAR T cells were detected in intestinal tissue more than 2 years after infusion in one patient, despite being undetectable in peripheral blood or bone marrow.
Some patients had no detectable mucosal CAR T-cell infiltration, indicating that persistent mucosal CAR T cells were not detected in every reported case.
Two patients treated with upadacitinib showed improvements in symptoms, fecal calprotectin, and body weight within 4 weeks.

The study characterized intestinal samples using single-cell and tissue-based analyses.

Two patients received the selective JAK1 inhibitor upadacitinib; the report describes clinical and biomarker improvements within 4 weeks.

In one patient analyzed after upadacitinib treatment, intestinal CAR T-cell density decreased from 193 to 39 cells per high-power field.
Reported measures included symptoms, fecal calprotectin, body weight, and intestinal tissue and immune findings.

CAR-TEC is described as a rare but serious gastrointestinal complication of BCMA-directed CAR T-cell therapy.
The study does not establish that persistent mucosal CAR T cells cause all cases of enterocolitis.

Patients with multiple myeloma who developed CAR-TEC after BCMA-directed CAR T-cell therapy; two patients received upadacitinib.

In two treated patients, symptoms, fecal calprotectin, and body weight improved within 4 weeks. The report provides no broader prescribing guidance.

Interpret the study findings as evidence of multiple intestinal inflammatory changes; B-cell and plasma-cell depletion alone did not explain the complication.
Recognize that mucosal CAR T-cell infiltration was not detected in every reported case.
The researchers state that prospective sampling before CAR T-cell infusion is needed to better establish causality and assess potential treatment targets.