DISCUSSION
Because AUL is an extremely rare disease, optimal treatment has not been
established and, particularly in relapsed/refractory cases, therapy
options are limited. A few B-lineage associated markers, such as CD22,
are expressed in some cases of AUL.4 Weinberg et al.
reported that 6 of 24 (25%) AUL cases showed partial or full CD22
co-expression,5 and in our case, CD22-positive AUL
indicated a treatment strategy using InO against relapsed/refractory
disease.
Use of InO increases the risk of VOD/SOS after stem cell
transplantation.14 Our patient also met the proposed
EBMT pediatric criteria for VOD/SOS.12 Although the
severity grading was moderate (grade II) and VOD/SOS improved
immediately with symptomatic
therapy in this case, careful judgment should be made regarding
administration of InO for AUL. Further accumulation of cases is needed
to allow evaluation of the efficacy and safety of InO as a bridging
therapy to stem cell transplantation in patients with CD22-positive AUL.