A paradoxical tuberculosis (TB) reaction is defined as the clinical or radiological worsening of pre-existing TB lesions or the development of new lesions during treatment. We treated a case of such a paradoxical reaction in a 21-day-old female infant who was diagnosed with congenital TB and was being treated with antituberculous drugs. The paradoxical reaction improved after additional treatment with corticosteroids. Therefore, corticosteroids might be useful to control paradoxical reactions in patients with congenital tuberculosis.

We report the outcome of 236 pediatric umbilical cord blood transplantations (UCBT) performed in Korea. Given that the sources of the grafts were mostly unrelated donors (n 5 226; 95.8%), only the results of unrelated UCBT were included for all statistics. The most frequent primary disease was acute leukemia (n 5 167). In total, 91.7% of recipients were seropositive for cytomegalovirus (CMV). The median doses of nucleated cells and CD341 cells were 4.84 3 10 7 /kg and 2.00 3 10 5 /kg, respectively. The median times to neutrophil (>0.5 3 10 9 /L) and platelet recovery (>20 3 10 9 /L) were 18 and 45 days, respectively. Grade 2-4 acute graft-versushost-disease (GVHD) and chronic GVHD developed in 41.1 and 36.1% of cases, respectively. Forty-five patients developed CMV disease. The 5-year overall and event-free survival were 47.5 and 36.9%, respectively. Multivariate analysis revealed that adverse factors for survival of the whole cohort were total body irradiation-based conditioning (P 5 0.007), salvage transplant (P 5 0.001), failure to achieve early complete chimerism (P < 0.0005), and CMV disease (P 5 0.001). The outcomes of the single-and double-unit UCBT (n 5 64) were similar, while double-unit recipients were heavier (P < 0.0005) and older (P < 0.0005). We conclude that double-unit UCBT is a reasonable option for older or heavier children and that the thorough surveillance of CMV infection and the development of an effective CMV therapeutic strategy may be especially important for Korean children, whose CMV seroprevalence exceeds 90%. Am. J. Hematol. 86:12-17, 2011. V

Background Knowledge of the roles of tacrolimus and minidose methotrexate (MTX) in the prevention of acute graft-versus-host disease (aGVHD) in pediatric allogeneic hematopoietic stem cell transplantation (HSCT) is limited. We retrospectively evaluated the engraftment status, incidence of aGVHD and chronic GVHD (cGVHD), and toxicities of tacrolimus and minidose MTX in aGVHD prophylaxis in children undergoing allogeneic HSCT. Methods Seventeen children, who underwent allogeneic HSCT and received tacrolimus and minidose MTX as GVHD prophylaxis from March 2003 to February 2011, were reviewed retrospectively. All the patients received tacrolimus since the day before transplantation at a dose of 0.03 mg/kg/day and MTX at a dose of 5 mg/m 2 on days 1, 3, 6, and 11. Results Of the 17 patients, 9 received human leukocyte antigen (HLA)-matched related donor transplants, and 8 received HLA-matched, or partially mismatched unrelated donor transplants. The median time for follow-up was 55 months. The incidence of aGVHD in the related and unrelated donor groups was 22.2% and 42.9%, respectively. cGVHD was not observed. To maintain therapeutic blood levels of tacrolimus, the younger group (<8 years of age) required an increased mean dose compared to the older group (≥8 years) ( P =0.0075). The adverse events commonly associated with tacrolimus included hypomagnesemia (88%), nephrotoxicity (23%), and hyperglycemia (23%). Conclusion Tacrolimus and minidose MTX were well tolerated and effective in GVHD prophylaxis in pediatric patients undergoing allogeneic HSCT. Children <8 years of age undergoing HSCT required increased doses of tacrolimus to achieve therapeutic levels.

Thymic hyperplasia results from thymic regrowth after atrophy during stressful conditions such as burns, surgery, infection, and chemotherapy. Although thymic lesions are relatively common causes of anterior mediastinal masses, they also can develop in other mediastinal compartments on rare occasions. It is well known that thymic tissue can develop in ectopic intrathoracic lesions. Few cases of ectopic thymus associated with disturbance during thymus embryogenesis have been reported as incidental findings. We report the case of a 4-year-old boy with true thymic hyperplasia from an ectopic thymus after successful treatment for Burkitt lymphoma. This is a rare finding in the differential diagnosis of a middle mediastinal mass in a child following chemotherapy for lymphoma. The diagnosis of thymic hyperplasia from an ectopic thymus can be confirmed only histologically.

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