Other Iatrogenic Immunodeficiency-Associated Lymphoproliferative Disorders

Other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OII-LPD) is defined by the World Health Organization classification 2016 as lymphoid proliferations or lymphomas that arise in patients treated with immunosuppressive drugs for autoimmune disease or conditions other than in the post-transplant setting. OII-LPD patients have a relatively high incidence of extranodal disease (40–50%). The distinct feature of OII-LPD is spontaneous regression after discontinuation of immunosuppressive drugs. The clinical course of OII-LPD after discontinuation of immunosuppressive drugs can be roughly divided into three categories: regression, transient regression followed by relapse or recurrence, and progression. Regression after discontinuation of immunosuppressive drugs was seen in 70% of OII-LPD patients. About 33% of these patients who experienced transient regression had experienced relapse or recurrence. The remaining 30% of patients were without regression even after discontinuation of immunosuppressive drugs. Higher absolute lymphocyte count in peripheral blood at the time of development of OII-LPD and Epstein-Barr virus-encoded RNA (EBER)-positivity are predictive factors of regression.