Abstract
Severe aplastic anemia (SAA) is probably an immune-mediated disorder, and immunosuppressive therapy is recommended for patients with no available donor for bone marrow transplant. Between October 1984 and November 1987, 25 consecutive children and adolescents with SAA with no HLA-compatible marrow donor received equine antithymocyte globulin (ATG) (15 mg kg-1 day-1) for 10 days. The patients were evaluated 6 weeks, 6 months, and 12 months after starting ATG treatment. Thereafter, patients were evaluated yearly until July 1998. Median age was 10 years (range, 1.5-20 years), granulocyte counts on referral ranged from 0.032 to 1.4 x 10(9)/l (median 0.256 x 10(9)/l), and 12 patients had granulocyte counts <0.2 x 10(9)/l. At a median follow-up of 9.6 years (range, 8.6-11.8 years), 10 patients (40%) remained alive with good marrow function. No morphologic evidence of hematological clonal disorders has been observed, although two patients probably have acquired clonal chromosomal abnormalities (trisomy 8 and del(6)q21, respectively). Responses to ATG were observed between 6 weeks and 6 months from the start of treatment in 60% of evaluable patients. The response rate was not different in patients whose granulocyte count at diagnosis was <0.2 x 10(9)/l, or in those who were <10 years of age. This study supports the view that, when compared with supportive measures, ATG is an effective treatment for children or adolescents with SAA. Although these results are inferior to those reported for marrow transplantation or more intensive immunosuppressive regimens, these patients who responded to ATG are long-term survivors with stable peripheral blood counts and a low rate of relapse.
Highlights
Severe aplastic anemia (SAA) is a heterogeneous group of disorders characterized by pancytopenia and bone marrow failure
This report is the first to describe a Brazilian sizable cohort of children treated with antithymocyte globulin (ATG) at one institution in which we investigated the quality of long-term marrow function (>10 years post-diagnosis) and examined factors associated with the hematologic response
We set out to characterize the quality of bone marrow function in long-term survivors of SAA who were initially managed with ATG
Summary
Severe aplastic anemia (SAA) is a heterogeneous group of disorders characterized by pancytopenia and bone marrow failure. Immunosuppressive treatment of aplastic anemia began after it was observed that autologous hematopoiesis was recovered in patients who rejected partially matched bone marrow after an antithymocyte globulin. The cytotoxicity of these agents to T lymphocytes, and the consequent reduced production of bone marrow inhibitory lymphokines are probably the chief mechanisms of action [6]. Evolution to other clonal hematologic disorders, such as paroxysmal nocturnal hemoglobinuria, myelodysplasia, and leukemia was observed, and patients with severe neutropenia (
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More From: Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas
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