Elevated tissue transglutaminase immunoglobulin A: Celiac disease or polytypic plasmacytosis?

We report a case of an adolescent girl post cardiac transplant with hypergammaglobulinemia and presumed celiac disease (CD), who had a persistently elevated anti-tissue transglutaminase immunoglobulin A despite a gluten free diet. Refractory CD and Crohn's disease were excluded. Concomitant dairy elimination led to normalization of celiac titers but no histological improvement. Ultimately, she was diagnosed with polytypic plasmacytosis from suspected immune dysregulation.