Split chimerism may be enough to cure Evans syndrome

Natural History, Pathogenesis, and Treatment of Evans Syndrome in Children

Primary Evans syndrome (ES) is defined by the concurrent or sequential occurrence of immune thrombocytopenia and autoimmune hemolytic anemia in the absence of an underlying etiology. The syndrome is characterized by a chronic, relapsing, and potentially fatal course requiring long-term immunosuppressive therapy. Treatment of ES is hardly evidence-based. Corticosteroids are the mainstay of therapy. Rituximab has emerged as the most widely used second-line treatment, as it can safely achieve high response rates and postpone splenectomy. An increasing number of new genetic defects involving critical pathways of immune regulation identify specific disorders, which explain cases of ES previously reported as "idiopathic".

Treatment of refractory ITP and Evans syndrome by haematopoietic cell transplantation: is it indicated, and for whom?

Several lines of therapy have been established for patients with immune thrombocytopenia (ITP) and Evans syndrome. However, these therapies generally require prolonged administration, lead to profound immunosuppression and increased infectious risk, and are often poorly tolerated. While most patients with these disorders will respond to first-line steroid therapy, others will prove refractory or intolerant to multiple treatments. In these patients (and possibly even selected patients who are not considered refractory), autologous or allogeneic haematopoietic stem cell transplantation (HCT) may provide definitive therapy. We review the literature on the treatment of ITP and Evans syndrome with HCT and discuss its use in the management of these disorders. We also pose, for the purpose of discussion, research questions that will be important to address if HCT is to be considered a viable option for more patients with these diseases.

Familial hemophagocytic lymphohistiocytosis: when rare diseases shed light on immune system functioning

The human immune system depends on the activity of cytotoxic T lymphocytes (CTL), natural killer (NK) cells, and NKT cells in order to fight off a viral infection. Understanding the molecular mechanisms during this process and the role of individual proteins was greatly improved by the study of familial hemophagocytic lymphohistiocytosis (FHL). Since 1999, genetic sequencing is the gold standard to classify patients into different subgroups of FHL. The diagnosis, once based on a clinical constellation of abnormalities, is now strongly supported by the results of a functional flow-cytometry screening, which directs the genetic study. A few additional congenital immune deficiencies can also cause a resembling or even identical clinical picture to FHL. As in many other rare human disorders, the collection and analysis of a relatively large number of cases in registries is crucial to draw a complete picture of the disease. The conduction of prospective therapeutic trials allows investigators to increase the awareness of the disease and to speed up the diagnostic process, but also provides important functional and genetic confirmations. Children with confirmed diagnosis may undergo hematopoietic stem cell transplantation, which is the only cure known to date. Moreover, detailed characterization of these rare patients helped to understand the function of individual proteins within the exocytic machinery of CTL, NK, and NKT cells. Moreover, identification of these genotypes also provides valuable information on variant phenotypes, other than FHL, associated with biallelic and monoallelic mutations in the FHL-related genes. In this review, we describe how detailed characterization of patients with genetic hemophagocytic lymphohistiocytosis has resulted in improvement in knowledge regarding contribution of individual proteins to the functional machinery of cytotoxic T- and NK-cells. The review also details how identification of these genotypes has provided valuable information on variant phenotypes.

Effectiveness of cyclosporine and mycophenolate mofetil in a child with refractory evans syndrome

Evans Syndrome is a rare autoimmune disease consisting of hemolytic anemia, thrombocytopenia and/or neutropenia. It may be associated with other autoimmune or lymphoproliferative diseases. Its course can be extremely serious and, rarely, even life-threatening; thus it represents a excellent treatment challenge for the pediatric hematologist. First line treatment consists of steroids and/or immunoglobulin; further therapy with rituximab, vincristine, cyclophosphamide and other immunosuppressive drugs can be considered in unresponsive patients. We describe a baby with refractory Evans Syndrome that was cured by prolonged administration of mycophenolate mofetil and remained disease-free for 4 years after the discontinuation of treatment.

Stem cell transplantation for patients with Evans syndrome

Evans syndrome (ES) is a chronic hematological disorder characterized by autoimmune hemolytic anemia and immune-mediated thrombocytopenia that often requires profound and long-term immunosuppression. Only a few small case series or single case studies of autologous and allogeneic hematopoietic stem cell transplantation (HSCT) in patients with ES have been reported in the literature, with long-term remissions being observed after both autologous and allogeneic HSCT. Patients with ES suffering from refractory disease, multiple relapses and serious disease-related complications should be offered allogeneic HSCT, which is the only treatment with curative potential. Autologous HSCT might be preferable in patients with serious pre-existing comorbidities lacking an HLA-identical donor. Owing to the rarity of this disease and the small number of patients receiving HSCT for ES, prospective controlled studies on this approach are not available. A prospective registration of patients transplanted for ES would allow the development of optimal transplant strategies.