Efficient recruitment of c-FLIPL to the death-inducing signaling complex leads to Fas resistance in natural killer-cell lymphoma.

Activation-induced cell death (AICD) mediated by the Fas/Fas ligand (FasL) system plays a key role in regulating immune response. Although normal natural killer (NK) cells use this system for their homeostasis, malignant NK cells seem to disrupt the process. Extranodal NK/T-cell lymphoma, nasal type (ENKL) is a rare but fatal disease, for which novel therapeutic targets need to be identified. We confirmed that ENKL-derived NK cell lines NK-YS and Hank1, and primary lymphoma cells expressed procaspase-8/FADD-like interleukin-1ß-converting enzyme (FLICE) modulator and cellular FLICE-inhibitory protein (c-FLIP), along with Fas and FasL. Compared with Fas-sensitive Jurkat cells, NK-YS and Hank1 showed resistance to Fas-mediated apoptosis in spite of the same expression levels of c-FLIP and the death-inducing signaling complex (DISC) formation. Unexpectedly, the long isoform of c-FLIP (c-FLIPL ) was coimmunoprecipitated with Fas predominantly in both ENKL-derived NK cell lines after Fas ligation. Indeed, c-FLIPL was more sufficiently recruited to the DISC in both ENKL-derived NK cell lines than in Jurkat cells after Fas ligation. Knockdown of c-FLIPL per se enhanced autonomous cell death and restored the sensitivity to Fas in both NK-YS and Hank1 cells. Although ENKL cells are primed for AICD, they constitutively express and efficiently utilize c-FLIPL , which prevents their Fas-mediated apoptosis. Our results show that c-FLIPL could be a promising therapeutic target against ENKL.

Vitamin B6 deficiency is prevalent in primary and secondary myelofibrosis patients.

Vitamin B6 (VB6) deficiency contributes to oncogenesis and tumor progression in certain cancers, and is prevalent in cancer patients in general. VB6 is also an essential element of heme synthesis, and deficiency can lead to anemia. Primary myelofibrosis (PMF) and secondary myelofibrosis (sMF) are myeloproliferative neoplasms often presenting with anemia along with other cytopenias. We performed a prospective study to determine whether PMF and sMF patients suffer from VB6 deficiency, and whether VB6-deficient patients show improvement of anemias with VB6 supplementation. Twelve PMF patients and 11 sMF patients were analyzed. A total of 16 of 23 patients (69.6%) were found to have VB6 deficiency, but VB6 supplementation with pyridoxal phosphate hydrate did not elevate hemoglobin levels in deficient patients. None of the patients presented with vitamin B12, iron, or copper deficiencies. Four patients showed serum folate levels below the lower limit of normal and eight patients showed serum zinc levels below the lower limit of normal; however, these deficiencies were marginal and unlikely to contribute to anemia. Compared to VB6-sufficient patients, VB6-deficient patients showed significantly lower serum folate levels and higher serum copper levels. Studies elucidating the relationship of VB6 deficiency and etiology of PMF/sMF are warranted.

Multiple Placental Infarcts in a Pregnant Woman with Essential Thrombocythemia.

Myeloproliferative neoplasms (MPNs), including polycythemia vera, essential thrombocythemia (ET), and primary myelofibrosis, mainly occur in older patients, but have also been reported in younger patients. A "second peak" occurs in female patients in their thirties, particularly in ET; thus, the management of pregnancy is often discussed. We herein present the case of a 33-year-old woman with a high platelet count and multiple placental infarcts during delivery who was subsequently diagnosed with ET. Although there are no worldwide guidelines for the management of MPNs in pregnancy, the risk of thrombosis is markedly increased in these patients, and antithrombotic therapy should be considered.

Acute exacerbation of organizing pneumonia leading to sudden death in a patient with sarcoidosis-lymphoma syndrome.

The subject was an 83-year-old female; she had a history of Propionibacterium acnes-related sarcoidosis at the age of 79 years. At diagnosis, she was treated with clarithromycin and achieved remission. Four years later, during a routine physical check-up, she presented with pulmonary opacities and swelling of multiple lymph nodes. A definitive diagnosis of lymphoma could not be made by inguinal lymph node biopsy. The patient's general condition was good, and we observed her clinical course. Oh the 56th day of her illness, she died suddenly. Autopsy revealed diffuse large B-cell lymphoma (DLBCL). Sarcoidosis-lymphoma syndrome (SLS) was diagnosed after sampling hyalinized nodules from both lungs. The cause of death was organizing pneumonia around an epithelioid granuloma and cor pulmonale. Organization markedly increased around the DLBCL. These findings might be associated with cor pulmonale. Although SLS often appears during chronic active sarcoidosis, sudden death is rare and there are few reports on SLS in Japan. We report this case along with a review of the literature.

Pulmonary Intravascular Large B-cell Lymphoma (IVLBCL) Disguised as an Asthma Exacerbation in a Patient with Asthma.

A 62-year-old man with asthma presented with a 1-month history of wheezing and exertional dyspnea. Although the wheezing symptoms disappeared after systemic corticosteroid therapy, the exertional dyspnea and hypoxemia did not improve. A diagnosis of intravascular large B-cell lymphoma (IVLBCL) with pulmonary involvement was suspected because of the increased serum lactic dehydrogenase (LDH) and soluble interleukin-2 receptor (sIL-2R) level, increased alveolar-arterial oxygen difference (AaDO2), decreased pulmonary diffusing capacity for carbon monoxide (DLCO) and scintigraphic, computed tomography (CT) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT findings. The patient was diagnosed as having IVLBCL with pulmonary involvement based on a pathological analysis of a random skin biopsy and a transbronchial lung biopsy. IVLBCL should be considered in patients with symptoms of asthma that are refractory to corticosteroid treatment.

Congenital haptoglobin deficiency discovered on the occasion of anaphylaxis induced by platelet concentrate transfusion.

A 77-year-old man with myelodysplastic syndrome suffered from duodenal perforation after undergoing endoscopic submucosal dissection (ESD) for treatment of duodenal cancer. He presented with hemorrhagic shock, peritonitis and disseminated intravascular coagulation (DIC), and received transfusions of red blood cells (RBC), fresh frozen plasma (FFP), γ-globulin and albumin (Alb). One month after the last RBC transfusion, prolonged thrombocytopenia was observed, and platelet concentrate (PC) was transfused. However, immediately after starting PC transfusion, he developed dyspnea, hypotension and rash, and was thus diagnosed as being in anaphylactic shock. Analysis of the patient's serum revealed absence of haptoglobin (Hp) and the presence of anti-Hp antibody. Further studies, using PCR detected Hpdel, yielded a diagnosis of congenital Hp deficiency. Thus, the anaphylactic shock was considered to have been induced by Hp in the transfused PC reacting with pre-existing anti-Hp antibodies. Thereafter, transfusions were safely carried out with the use of washed PC. Congenital Hp deficiency is relatively prevalent, and in such cases transfusions should be carried out using washed RBC, washed PC and congenital Hp deficiency donor derived FFP to avoid anaphylactic transfusion reactions. Transfusions would be even safer if production of congenital Hp deficiency donor derived PC were to be made available in the future.

Plasmablastic lasmablastic lymphoma of the duodenal and jejunum.

Plasmablastic lymphoma (PBL) is a rare B-cell neoplasm with an aggressive clinical behavior that predominantly occurs in the oral cavity of human immunodeficiency virus (HIV)-positive patients. HIV-negative PBL has not been extensively reported. A 65-year-old female presented with anemia, who was HIV-negative. Gastrointestinal fiberscope (GIF), and colon fiberscope (CF) were performed. However, we could not detect the bleeding sites. We detected the tumor by capsule endoscopy, and obtained the tumor cells from the duodenal and jejunal sites. The neoplastic cells were diffusely positive for CD56, epithelial membrane (EMA), CD4, λ, and EBV-encoded RNA1 (EBER1) and partially positive for CD138 and CD79a. This patient was diagnosed as PBL. The small intestine is a rare extra-oral site of involvement in PBL patients, and only four cases in HIV-negative patients have been reported.

Expression of Epstein-Barr virus-encoded proteins in extranodal NK/T-cell Lymphoma, nasal type (ENKL): differences in biologic and clinical behaviors of LMP1-positive and -negative ENKL.

PURPOSE: Extranodal NK/T-cell lymphoma, nasal type (ENKL) is closely associated with Epstein-Barr virus (EBV). To elucidate its pathogenetic role, we examined the expression profiles of EBV-encoded proteins, especially focusing on latent membrane protein 1 (LMP1). EXPERIMENTAL DESIGN: Immunohistochemistry was carried out using clinical samples from ENKL cases, which were diagnosed between 1996 and 2010 at our institution. We statistically assessed the correlation between LMP1 positivity and the clinicopathologic data and further examined phosphorylation status of NF-κB RelA and Akt in ENKL cell lines. RESULTS: Most of the 30 examined cases showed pleomorphic morphology, natural killer cell immunophenotype, and a localized disease. Immunohistochemistry detected EBERs, but not EBNA2, in all cases. LMP1 and LMP2A were positive in 22 (73.3%) and 12 cases (40.0%), respectively. LMP1-positive cases tended to show a localized disease (P = 0.060, the Fisher exact test). Nuclear localization of phosphorylated RelA and detection of phosphorylated Akt were predominantly observed in LMP1-positive cases (P = 0.002 and P < 0.001, respectively, the Fisher exact test). RNA silencing experiments of LMP1 in Hank1 cells suggested a positive correlation between LMP1 expression and phosphorylation of RelA and Akt. With a median follow-up period of 26.7 months (range, 0.2-142.3 months), the 2.5-year overall survival rates for LMP1-positive and -negative cases were estimated at 78.3% and 12.5%, respectively (P = 0.001, log-rank test). CONCLUSIONS: LMP1 expression shows correlations with phosphorylation of RelA and Akt and possibly has a favorable impact on clinical outcome in ENKL.

Neural cell adhesion molecule (CD56)-positive B-cell lymphoma.

Expression of neural cell-adhesion molecule CD56 is a rare event in B-cell lymphoma. We described four cases of CD56-positive B-cell lymphoma, including follicular lymphoma and diffuse large B-cell lymphoma. These lymphoma cells expressed CD10 and bcl-6, which suggests germinal center-stage phenotype. Immunohistochemistry showed that CD56-positive cells aggregated and displayed a cohesive growth pattern, indicating that homotypic adhesion through the molecules might affect the manner of tumor growth and expansion. Although CD56 expression level varies among the cases, this molecule might play some roles in the manner of growth and expansion of CD56-positive B-cell lymphomas.