was shown to be superior to horse ATG in head-to-head
comparison.20---22 However, when given as first therapy, outcomes
with rabbit ATG were inferior to horse ATG in a
randomized study.8 Follow-up retrospective reports have
confirmed a lower response rate in patients treated with rabbit
ATG as first therapy when compared to horse ATG.23---26
However, the majority of the reports have not focused on
children. This article aimed to report the results in pediatric
patients who received rabbit ATG as first therapy for
SAA treated at the Instituto da Crianc¸a of the Universidade
de São Paulo, São Paulo, Brazil.
Patients and Methods
Patients
This study included consecutive patients with SAA who
received rabbit ATG/CsA between August of 1996 and of
June 2011 at the Instituto da Crianc¸a of the Universidade
de São Paulo. Due to the unavailability of the horse ATG
in this service and in Brazil since 2007, rabbit ATG became
the standard immunosuppressor in SAA patients without an
HLA-identical sibling donor. All patients met the criteria for
SAA, defined as a bone marrow cellularity of less than 30%
and severe pancytopenia with at least two of the following
peripheral blood count criteria: (1) absolute neutrophil
count (ANC) < 0,5 x 109/lL (2) absolute reticulocyte count
(ARC) < 60x109/L; platelet count < 20x109/L.27 Exclusion
criteria were: (1) abnormal cytogenetics, (2) bone marrow
morphology consistent with myelodysplasia, and (3) diagnosis
of Fanconi anemia. Bone marrow biopsy and aspirate,
including cytogenetics, were performed before initiating
therapy. Fanconi anemia was excluded by the absence of
chromosomal changes after exposure in vitro of lymphocytes