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Evidence for hematopoietic stem cell transplantation (HCT) in autoimmune disease has been building since the 1990s; however, many clinicians may not yet be aware of its applications to autoimmune disease. We review the basic tenets of HCT and evidence for autologous HCT in multiple sclerosis (MS), systemic sclerosis (SSc), and lupus with an emphasis on recent advanced phase trials. In MS, the phase 3 randomized MIST trial and the phase 2 randomized ASTIMS trial demonstrated the efficacy of autologous HCT in refractory MS over disease-modifying therapies and mitoxantrone, respectively. In SSc, the phase 3 randomized ASTIS trial and the phase 2 randomized SCOT trial demonstrated the efficacy of autologous HCT in advanced SSc compared to cyclophosphamide. The evidence for HCT in autoimmune diseases continues to grow, particularly in MS and SSc. In lupus, large, comparative trials are still needed. Across autoimmune diseases, questions that still remain to be answered include optimizing patient selection to limit TRM, the appropriate use of MAC, and the necessity for graft manipulation. Furthermore, collaboration between disease-specific and transplant physicians is imperative to expand the appropriate use of HCT in routine clinical practice.

The goal of this review is to provide the reader with an updated summary of the cutaneous manifestations of systemic sarcoidosis, with a particular emphasis on the predilection of sarcoidosis for scars, tattoos, and other areas of traumatized skin. While the mechanism underlying the propensity for traumatized skin to develop sarcoidosis lesions remains unclear, several theories have been proposed including the idea that cutaneous sarcoidosis represents an exuberant, antigen-driven foreign-body response, as well as the theory that traumatized skin represents an immunocompromised district with altered local immune trafficking and neural signaling. In this review, we present two cases in which the development of cutaneous lesions in scars and tattoos was integral to the diagnosis of systemic sarcoidosis. We then review the various cutaneous manifestations of systemic sarcoidosis, the clinical characteristics and differential diagnosis of scar and tattoo sarcoidosis, the proposed mechanism by which traumatized skin is prone to developing sarcoidosis lesions, and current treatments for cutaneous sarcoidosis.

Hypersensitivity reactions of the immune system have been broadly categorized into the atopic and autoimmune depending on whether the antigen triggering the reaction is endogenous (or self) or exogenous, the types of cellular and humoral components involved, and the clinical symptoms. Research into the pathophysiology of the resultant disease states has focused on a dichotomy between Th1 and Th2 T helper lymphocytes thought to govern autoimmune and atopic disease, respectively. Recent discoveries, however, have served to dispute this paradigm and have provided additional insight into the roles of Th17 cells, B-lymphocytes and T regulatory cells as well as the considerable communication and commonalities between the complex signaling pathways. Furthermore, clinical studies have served to challenge the idea that the presence of atopy and autoimmunity are mutually exclusive states. Finally, application of recent approaches to treatment-biologic targeted therapy in autoimmunity and induction of immune tolerance in atopic disease--to both disease states have shown mixed but promising results.