A rare case of osteomyelitis of the tibia caused by Mycobacterium fortuitum which developed after closed intramedullary Küntscher nail fixation is reported. After extraction of the nail, combination therapy with antituberculous drugs, ofloxacin, and interleukin 2 was undertaken and bony union was achieved. Since a bone cyst formed during union, curettage and conventional cancellous bone grafting were performed. The patient is now pain-free even with prolonged weight-bearing. The success of treatment in this case is in contrast to other reports of the disease.

Werner syndrome (WS) confers a high risk of the development of neoplasias, including hematological malignancies, and curative treatment for these malignancies is difficult to achieve. A 44-year-old man with myelodysplastic syndrome was admitted to our hospital. He was diagnosed with mutation-proven WS. He underwent cord blood transplantation (CBT) following fludarabine, busulfan, and melphalan administration. A chimerism analysis of his marrow blood on day 62 showed a donor pattern >95%, which confirmed engraftment. The patient lived for 15 months while maintaining remission of MDS without treatment-related toxicity. Our case shows that CBT can be a treatment modality for WS patients with hematological malignancies.

Donor cell-derived leukemia and myelodysplastic syndrome (DCL) is a rare complication in patients after allogenic stem cell transplantation (SCT). Since 1971, numerous cases of DCL have been reported, but the detailed mechanisms of DCL are still unclear. A patient with jumping translocations (JTs) of 1q in umbilical cord blood donor cell-derived myelodysplastic syndrome (MDS), which likely occurred due to genetic alterations of TET2 and ASXL1 after cord blood transplantation (CBT), was examined in this study. Previously reported DCL cases after CBT that focused on the cytogenetic and molecular characteristics of these patients and patient outcome were reviewed. A total of 30 cases of DCL after CBT were identified between 2005 and 2018. The median time from CBT to the development of DCL was 16 months. The number of patients with DCL who were diagnosed with acute myeloid leukemia (AML) and MDS was 19 and 8, respectively. JTs were frequently observed in 5 of 27 DCL patients who had cytogenetic abnormalities, including our patient. Molecular abnormalities were described in 7 of the cases, and the most frequent abnormality was an NPM1 mutation. Other gene mutations that were usually found in de novo MDS or AML were observed in JT-DCL after CBT. From these results, chromosomal abnormalities such as JTs that occur subsequent to genetic alterations were seemed an important mechanisms underlying DCL onset in patients after CBT. Further molecular analyses regarding the genetic alterations of JTs are required to understand the pathogenesis of umbilical cord blood-derived JT-DCL.

We herein describe the case of a 60-year-old man with a history of Behçet's disease and myelodysplastic syndrome who received cord blood transplantation (CBT). The patient was given anti-thymocyte globulin conditioning and tacrolimus to prevent graft-versus-host disease. Two months after CBT, his blood Tac concentration measured by an antibody-conjugated magnetic immunoassay (ACMIA) was found to have increased >4-fold, even after the Tac treatment was stopped. This false response was caused by the interference of endogenous heterophilic antibodies with ACMIA. Therefore, physicians must be aware of possible false ACMIA results for patients with a history of autoimmune disease and/or treated by xenogeneic antibody therapy.

．はじめに