Cyclosporin A in aplastic anemia--report of a workshop

Mass cytometry analysis identifies T cell immune signature of aplastic anemia and predicts the response to cyclosporine

Aplastic anemia (AA) is an auto-activated T cell-mediated bone marrow failure. Cyclosporine is often used to treat non-severe AA, which demonstrates a more heterogeneous condition than severe AA. The response rate to cyclosporine is only around 50% in non-severe AA. To better predict response to cyclosporine and pinpoint who is the appropriate candidate for cyclosporine, we performed phenotypic and functional T cell immune signature at single cell level by mass cytometry from 30 patients with non-severe AA. Unexpectedly, non-significant differences of T cell subsets were observed between AA and healthy control or cyclosporine-responder and non-responders. Interestingly, when screening the expression of co-inhibitory molecules, T cell trafficking mediators, and cytokines, we found an increase of cytotoxic T lymphocyte antigen 4 (CTLA-4) on T cells in response to cyclosporine and a lower level of CTLA-4 on CD8⁺ T cells was correlated to hematologic response. Moreover, a decreased expression of sphingosine-1-phosphate receptor 1 (S1P₁) on naive T cells and a lower level of interleukin-9 (IL-9) on T helpers also predicted a better response to cyclosporine, respectively. Therefore, the T cell immune signature, especially in CTAL-4, S1P₁, and IL-9, has a predictive value for response to cyclosporine. Collectively, our study implies that immune signature analysis of T cell by mass cytometry is a useful tool to make a strategic decision on cyclosporine treatment of AA.

A promising immunosuppressive strategy of cyclosporine alternately combined with levamisole is highly effective for moderate aplastic anemia

The appropriate management of patients with moderate aplastic anemia (mAA) remains to be unclear and controversial. A cohort of 118 patients with mAA received a novel immunosuppressive strategy of cyclosporine alternately combined with levamisole (CSA and LMS regimen), which included 42 newly diagnosed and 76 chronic (disease duration >6 months) cases. CSA and LMS regimen was orally administrated with the initial dose of CSA 3 mg/kg per day in adults or 5 mg/kg per day in children, and LMS 150 mg per day in adults or 2.5 mg/kg per day in children, continued for 12 more months after achieving maximal hematologic response, followed by a slow tapering. The overall response rates were of 100 and 86.8 % for newly diagnosed and chronic group, respectively. The 24-month progression-free survival were 95.2 % (95 % confidence intervals [CI], 85.9-100 %) and 93.6 % (95 % CI, 86.9-100 %) for newly diagnosed and chronic group, respectively (P = 0.50). The 2-year event-free survival for the patients in newly diagnosed group (86.6 %; 95 % CI, 70.4-100 %) was superior to that in chronic group (57.0 %; 95 % CI, 43.5-70.4 %, P = 0.001). To date, 11 patients relapsed and no patients evolved to clonal disorders. Thus, CSA and LMS regimen represents a promising immunosuppressive strategy for mAA.

Immunosuppressive treatment of aplastic anemia with antithymocyte globulin and cyclosporine

Immunosuppression is the treatment modality for the majority of patients with aplastic anemia, most of whom are not candidates for allogeneic stem-cell transplantation. Antithymocyte globulin (ATG) or antilymphocyte globulin (ALG) have proven to be essential components of all regimens. Initial response rates can be improved by the addition of cyclosporine A (CsA), and this combination has become the standard of care for appropriate patients. Several new approaches to immunosuppression are being studied, including the optimal timing of administration of these drugs, the use of novel immunosuppressive agents, and the addition of early- and late-acting hematopoietic growth factors.

Practical aspects in the diagnosis and management of aplastic anemia

Aplastic anemia may result from several pathogenic mechanisms, the most common is idiopathic. The current definitive treatments for aplastic anemia are bone marrow transplantation (BMT) or immunosuppressive (IS) therapy. The benefits of each are comparable. However, certain subsets of patients derive superior benefit from one or the other. Bone marrow transplantation is the initial treatment of choice for young patients (< 20 years old). It results in the complete reconstitution of hematopoiesis, whereas autologous hematopoietic remissions after IS therapy are more susceptible to relapse. Survival rates after BMT, in patients between the ages of 20 and 40, are comparable to those reported for IS therapy. Better survival rates after BMT have been achieved with improved conditioning regimens and graft-versus-host disease prophylaxis. For patients older than 40, the treatment of choice is IS. Long-term complications of IS therapy include recurrence and development of clonal myeloid disorders. Long-term complications after BMT include graft-versus-host disease and secondary neoplasms. The IS regimen includes the combination of antithymocyte globulin and cyclosporin A. The addition of growth factor to the IS regimen seems promising; however, their use on their own is not recommended. Androgens have been shown to be inferior in the treatment of aplastic anemia. The role of BMT from an unrelated donor is being investigated.