CD4 and pancreatitis: Thus, CD3, CD4, and CD8 lymphocytic infiltration of pancreatic acini and interlobular septa with resultant acinar damage, ductitis, and venulitis likely represents an important histologic pattern of ICI-related pancreatitis (type 3 AIP), a condition that, to our knowledge, has only rarely been diagnosed on biopsy, resected specimens, or autopsy [15–30].