Hematopoietic Stem Cell Transplantation for Systemic Sclerosis: Review of Current Status

Three prospective controlled clinical trials and numerous small series and case reports have confirmed that durable, drug-free remission in systemic sclerosis is possible via an autologous hematopoietic stem cell transplantation. Similar results have been seen in other autoimmune diseases. The exact mechanism by which this immune "reset" was achieved in some but not all cases remains elusive, but includes major reduction of autoreactive immune competent cells, re-establishment of T- and B cell regulatory networks and normalization of tissue niche function, particularly vascular. Some aspects regarding mobilization, conditioning and graft manipulation still remain open, but clearly a significant toxicity is associated with all effective regimens at present, and therefore patient selection remains a key issue. In the hematology/oncology arena, major efforts are being made to reduce genotoxic and other collateral toxicity induced by current mobilization and conditioning protocols, which may also translate to autoimmune disease. These include developments in rapid mobilization and antibody drug conjugate conditioning technology. If effective, such low-toxicity regimens might be applied to autoimmune disease at an earlier stage before chronicity of autoimmunity has been established, thus changing the therapeutic paradigm.