Orbital lymphocyte populations in three states of thyroid eye disease

PURPOSE: We report histopathologic orbital tissue analysis from three patients with thyroid eye disease (TED) – active, chronic, and post-teprotumumab to better characterize orbital cellular populations in these varying states of TED. OBSERVATIONS: Orbital tissues in TED demonstrate minimal lymphocytic infiltration in fat and Mueller's muscle. Following teprotumumab treatment, the tissues were devoid of lymphocytes with only perivascular cuffs of T-lymphocytes remaining in orbital fat. CONCLUSIONS AND IMPORTANCE: In active TED, post-teprotumumab treatment, and in quiescent TED, orbital fat may not show significant inflammatory infiltration. More work is warranted to characterize specific cellular effects of teprotumumab and other biologics.