Hirotoshi Tokunaga

Philadelphia chromosome-positive acute lymphoblastic leukemia with extramedullary and meningeal relapse after allogeneic hematopoietic stem cell transplantation that was successfully treated with dasatinib

Central nervous system (CNS) relapse is a critical issue while treating Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). A 58-year-old woman with Ph-positive ALL who relapsed after bone marrow transplantation for meningeal leukemia was treated with high-dose methotrexate, which resulted in remission. She underwent allogeneic cord blood transplantation followed by reduced intensity conditioning chemotherapy with imatinib; however, she experienced CNS relapse and developed an extramedullary mass on the right side of the temporal region. We treated 40 mg of dasatinib once daily, which had to be temporarily discontinued because she developed grade 2 pleural effusion and grade 2 hematemesis. After reinitiation of dasatinib, the extramedullary mass disappeared and meningeal leukemia ameliorated almost immediately. With 40 mg dasatinib administered once daily, its trough level and cerebrospinal fluid (CSF) concentration were 32 ng/mL and below the sensitivity threshold of 1 ng/mL, respectively. Treatment was continued, and the patient remained in complete remission until she died of pneumonia 7 years after the initial diagnosis of ALL. Dasatinib can be an effective treatment for Ph-positive ALL with CNS relapse. Although the concentration in the CSF seems low, it may be sufficient to exert anti-leukemic effects in the human CNS.

The pandemic (H1N1) 2009 influenza virus is resistant to mannose-binding lectin

BackgroundMannose-binding lectin (MBL) is an important component of innate immunity because it promotes bacterial clearance and neutralization of human influenza A viruses. Since a majority of humans have no neutralizing antibody against the pandemic (H1N1) 2009 influenza (pandemic 2009) virus, innate immunity may be crucial and MBL susceptibility may therefore influence viral pathogenesis.ResultsWe examined MBL susceptibility of influenza A viruses and observed that the pandemic 2009 virus was resistant to MBL, whereas all seasonal influenza A viruses tested were susceptible. The mortality of mice infected with a seasonal H1N1 influenza virus was evidently enhanced on transient blockage of MBL activity by simultaneous inoculation of mannan, whereas mannan inoculation had no effect on mice infected with a pandemic 2009 virus. This indicates that MBL protects mice against infection with the seasonal virus but not against that with the pandemic 2009 virus.ConclusionsThese results indicate that the pandemic 2009 virus is not susceptible to MBL, an important component of innate immunity.

Re-emergence of H3N2 strains carrying potential neutralizing mutations at the N-linked glycosylation site at the hemagglutinin head, post the 2009 H1N1 pandemic

BackgroundSeasonally prevalent H1N1 and H3N2 influenza A viruses have evolved by antigenic drift; this evolution has resulted in the acquisition of asparagine (N)-linked glycosylation sites (NGSs) in the globular head of hemagglutinin (HA), thereby affecting the antigenic and receptor-binding properties, as well as virulence. An epidemiological survey indicated that although the traditional seasonal H1N1 strain had disappeared, H3N2 became predominant again in the seasons (2010–11 and 2011–12) immediately following the H1N1 pandemic of 2009. Interestingly, although the 2009 pandemic H1N1 strain (H1N1pdm09) lacks additional NGSs, clinically isolated H3N2 strains obtained during these seasons gained N (Asn) residues at positions 45 and 144 of HA that forms additional NGSs.MethodsTo investigate whether these NGSs are associated with re-emergence of H3N2 within the subtype, we tested the effect of amino acid substitutions on neutralizing activity by using the antisera raised against H3N2 strains with or without additional NGSs. Furthermore, because the N residue at position 144 of HA was identified as the site of mismatch between the vaccine and epidemic strains of 2011–2012, we generated mutant viruses by reverse genetics and tested the functional importance of this particular NGS for antibody-mediated neutralization by intranasal inoculation of mice.ResultsThe results indicated that amino acid substitution at residue 144 significantly affected neutralization activity, acting as an escape mutation.ConclusionsOur data suggest that the newly acquired NGSs in the HA globular head may play an important role in the re-emergence of endemic seasonal H3N2 strain by aiding the escape from humoral immunity.

Severe Colitis Associated with both Epstein-Barr Virus and Cytomegalovirus Reactivation in a Patient with Severe Aplastic Anemia

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are members of the herpesvirus family and common causes of viral infection in humans. CMV infection of the gastrointestinal tract occurs mainly in immunocompromised individuals, on the other hand EBV infection and reactivation involving the gastrointestinal tract is very rare. A 56-year-old man was diagnosed with severe aplastic anemia and treated with antithymocyte globulin (ATG) and cyclosporine (CSP). After 2 years of ATG/CSP therapy, he suddenly started passing bloody diarrhea and developed a high fever despite CSP treatment. Endoscopic features included severe edema and multiple superficial ulcers; the patient was initially diagnosed with severe colitis resembling inflammatory bowel disease (IBD). However, his symptoms did not resolve with steroid treatment. Immunohistochemical analysis of samples obtained from a second colonoscopy showed cells positive for CMV, and in situ hybridization revealed EBV-encoded small RNA-1-positive cells. Additionally, the patients serum was positive for C7-HRP, and both blood and colon tissues were positive for EBV DNA, which was detected using PCR analysis. We finally diagnosed the patient with colitis associated with reactivation of both CMV and EBV. The patient remains diarrhea-free after 1.5 years with scheduled globulin treatment and after cessation of immunosuppressive drug therapy. To our knowledge, this is the first reported case of an immunodeficient patient with severe hemorrhagic colitis that was associated with reactivation of both EBV and CMV, and whose endoscopic findings mimicked IBD.

Primary colorectal lymphoma comprising both components of diffuse large B-cell lymphoma and mucosa-associated lymphoid tissue lymphoma combined with cytomegalovirus colitis

A 16-year-old girl presented to our hospital with diarrhea and abdominal pain. The macroscopic findings of colonoscopy revealed multiple submucosal tumors and multiple ulcers, which were localized in the sigmoid colon, and diffuse granular mucosa which extended to the total colon. The pathological diagnosis was malignant lymphoma comprising both components of diffuse large B-cell lymphoma (DLBCL) and mucosa-associated lymphoid tissue (MALT) lymphoma, because the large lymphoma cells were CD20+, CD10−, and CD5−. Furthermore, immunohistochemical analysis of colorectal biopsy samples from multiple ulcers revealed cytomegalovirus (CMV)-positive cells. The patient was diagnosed with primary colorectal lymphoma comprising both components of DLBCL and MALT lymphoma combined with CMV colitis. She received anti-viral medication and chemotherapy.

A prospective multicenter phase II study of intrabone marrow transplantation of unwashed cord blood using reduced-intensity conditioning

Cord blood transplantation (CBT) is associated with delayed hematopoietic recovery and graft failure. To overcome these problems, we conducted a prospective, multicenter phase II study of intrabone marrow transplantation in which patients received reduced‐intensity conditioning without anti‐thymocyte globulin (ATG). The primary endpoint was the probability of full donor engraftment. Forty patients with hematologic malignancies were enrolled. Cord blood (CB) cells were injected without washing into 4 iliac bone sites (2 at each hemipelvis), at which approximately 6 mL of CB was administered at one site with local anesthesia. Full donor engraftment rate was 86.8%. The cumulative incidence of neutrophil and platelet engraftment was 86.4% and 85.5%, respectively. The median time to neutrophil (>0.5 × 109/L) and platelet (2.0 × 109/L) recovery was 17.5 and 44 days, respectively. The probability of severe acute graft‐vs‐host disease (GVHD) was 47.5%. The cumulative incidence of extensive chronic GVHD was 3.0%. The probability of relapse and non‐relapse mortality was 30.4% and 28.0%, respectively. The survival rate at 3 years was 45.6%, although most patients were at an advanced stage. These results suggest that our intrabone marrow‐CBT procedure without using ATG improves hematopoietic recovery and decreases the incidence of chronic GVHD, but does not decrease the incidence of acute GVHD.