Janus kinases (Jaks) play an important role in signal transduction via cytokine receptors. Tyk2 is a Janus kinase, and we developed tyk2-deficient mice to study the requirement for tyk2 in vivo. Tyk2-deficient mice show no overt developmental abnormalities; however, they display a lack of responsiveness to a small amount of IFNalpha, although a high concentration of IFNalpha can fully transduce its signal even in the absence of tyk2. Furthermore, IL-12-induced T cell function is defective in these mice. In contrast, these mice respond normally to IL-6 and IL-10, both of which activate tyk2 in vitro. These observations demonstrate that tyk2 plays only a restricted role in mediating IFNalpha-dependent signaling while being required in mediating IL-12-dependent biological responses.

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Since granulocyte colony-stimulating factor (G-CSF) is thought to be a granulocyte lineage-specific cytokine, G-CSF receptors on blood cells other than those of granulocyte or monocyte lineage have not been well investigated. We now report that G-CSF receptors are present on platelets. The expression of G-CSF receptors on platelets was demonstrated by flow cytometry and radioreceptor assay. The mean number of G-CSF-binding sites per cell was 41 and the binding affinity was high (Kd 300 pM), similar to the affinity observed on granulocytes. Cross-linking assay revealed that G-CSF receptors were present on a single subunit protein of approximately 150 kD on the platelets. To clarify whether or not G-CSF might produce some direct functional influence on platelet response, the effects on platelet aggregation were studied. Although G-CSF itself did not affect platelet aggregation in vitro, preincubation with G-CSF augmented a secondary aggregation of platelets induced by low concentrations of adenosine diphosphate (ADP). There was a dose-response relationship for this G-CSF activity at concentrations of up to 10 ng/ml. Furthermore, the augmented ADP-induced secondary aggregation of platelets on G-CSF receptors was completely abrogated in the presence of anti-G-CSF polyclonal antibodies. These results indicate that platelets possess functional G-CSF receptors. (J.

Purpose: Extranodal NK/T-cell lymphoma, nasal type (ENKL) is an Epstein-Barr virus (EBV)-associated lymphoma for which a new chemotherapeutic regimen called SMILE (steroid, methotrexate, ifosfamide, L-asparaginase, and etoposide) recently showed promising results.Experimental Design: The amount of EBV-DNA was prospectively measured in whole-blood and plasma samples by real-time quantitative PCR from 26 patients registered in the SMILE phase II study.Results: Before treatment, the EBV-DNA was detected in 22 samples of whole blood with a median number of 3,691 copies/mL (range: 0-1.14 Â 10 7 ), but 15 samples of plasma with a median of 867 copies/mL (range: 0-1.27 Â 10 7 ). Results of these 2 measurements of EBV-DNA well correlated (R 2 ¼ 0.994, P < 0.001). The overall response rate to SMILE was significantly higher in patients with less than 10 5 copies/mL of EBV-DNA in whole blood at enrollment (90% vs. 20%, P ¼ 0.007) and in patients with less than 10 4 copies/mL of EBV-DNA in plasma (95% vs. 29%, P ¼ 0.002). The incidence of grade 4 toxicity of SMILE other than leukopenia/neutropenia was significantly higher in patients with 10 5 copies/mL of EBV-DNA or more in whole blood (100% vs. 29%, P ¼ 0.007) than that of others and in patients with 10 4 copies/mL or more in plasma (86% vs. 26%, P ¼ 0.002). Conclusions: These findings suggest that whole blood is more sensitive for clinical use than plasma. The EBV-DNA amount in whole blood was useful for predicting tumor response, toxicity, and prognosis after SMILE chemotherapy for ENKL. Clin Cancer Res; 18(15); 4183-90. Ó2012 AACR.

Sixty-four cases of malignant lymphoma involving the liver were examined. Of these, 20 cases were histologically confirmed to be primary hepatic B-cell lymphoma. Twelve of these 20 cases were diffuse large B-cell lymphoma (DLBCL) and eight cases were mucosa-associated lymphoid tissue (MALT) lymphoma. Of the 12 cases of DLBCL, six were immunohistologically positive for CD10 and/or Bcl6 (indicating a germinal center phenotype), six were positive for Bcl2, and five were positive for CD25. Eight of the 12 DLBCL cases (66.7%) and two of the eight MALT lymphoma cases (25%) had serum anti-hepatitis C virus (HCV) antibodies and HCV RNA. The incidence of HCV infection was significantly higher in the hepatic DLBCL cases than in systemic intravascular large B-cell cases with liver involvement (one of 11 cases, 9.1%) and T/NK-cell lymphoma cases (one of 19 cases, 5.3%) (p < 0.01 for both). Two hepatic DLBCL cases (16.7%) had rheumatoid arthritis treated with methotrexate, and four MALT lymphoma cases (50%) had Sjögren’s syndrome, primary biliary cirrhosis, or autoimmune hepatitis; one case in each of these two groups was complicated by chronic HCV-seropositive hepatitis. Although primary hepatic lymphoma is rare, persistent inflammatory processes associated with HCV infection or autoimmune disease may play independent roles in the lymphomagenesis of hepatic B cells.

Bacterial 16S ribosomal RNA genes (rDNA) were detected in blood samples from two healthy individuals by PCR under conditions involving 30 cycles that did not produce any visible products from negative control saline. Even from control samples, PCR involving 35-40 cycles yielded visible bands. Major clones detected in the blood samples, but not in control, were the Aquabacterium subgroup, Stenotrophomonas subgroup, Budvicia subgroup, Serratia subgroup, Bacillus subgroup and Flavobacteria subgroup. No clone was located within the bacteroides-clostridium-lactobacillus cluster, which is indigenous to gastrointestinal flora.Key words bacteremia, blood, polymerase chain reaction, 16S ribosomal RNA.Diagnosis of bacterial infection and identification of the agent responsible is essential in clinical medicine, and has been traditionally carried out by inoculating blood or infected tissues into a liquid or solid nutrient medium. This approach has a limitation in that it can detect only bacteria and fungi that are culturable in a laboratory. Recently, PCR using species-specific primers (1-5) and nucleic acid sequence-based amplification (NASBA) (6) have also been used as an alternative approach for detecting agents that are responsible for infection.These techniques can also be used for detailed analysis of microbial biota in the oral cavity and gastrointestinal tract, using universal primers that anneal to conserved regions in the 16S ribosomal RNA gene (rDNA) or gyr B gene (7-9). It is reported that half of the bacteria comprising the oral and intestinal flora have not been previously identified by in vitro culture procedures (10). Moreover, recent studies using PCR have raised the possibility that bacterial DNA may be present in the human bloodstream (11-13). Our ultimate objective is to elucidate the role of such subclinically infecting unculturable or latent bacteria in the pathogenesis of chronic vascular diseases (14-16). As a first step, we investigated whether bacteria can translocate in some way from the oral and intestinal flora to the blood stream in 'healthy' humans. In this preliminary study, blood specimen-specific bacterial sequences were detected by PCR of rDNA. However, they were not representative of sequences found in human intestine.PCR was done with a REDExtract-N-Amp Blood PCR kit (Sigma-Aldrich Japan, Tokyo, Japan) using broadrange 16S ribosomal RNA gene (rDNA)-specific oligonucleotide primers. The PCR kit does not require any type of purification, organic extraction, centrifugation or alcohol precipitation, and can be used with whole blood.For blood sampling, the skin was first sterilized with a cotton swab moistened with popidone iodide, the anterior brachial median vein was punctured using a sterile 21-gauge needle (Terumo Corporation, Tokyo, Japan),

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A growing body of evidence indicates that genetic factors are involved in an increased risk of infection. We investigated whether mannose-binding lectin (MBL) gene polymorphisms that cause low levels of MBL are associated with the occurrence of major infections in patients, mainly bearing hematological malignancies, after high-dose chemotherapy (HDT) rescued by autologous peripheral blood stem cell transplantation (auto-PBSCT). A retrospective evaluation of 113 patients treated with HDT and auto-PBSCT revealed that the low-producing genotypes, B/B and B/LXA, were associated with major bacterial infection (P ¼ 0.0016, OR 7.9). We next performed a nation-wide large-scale study to assess the allele frequency of the MBL coding mutation in a total of 2623 healthy individuals in Japan. The frequency of allele B was estimated to be B0.2, almost the same in seven different areas of Japan. This common occurrence suggests that MBL deficiency may play an important role in the clinical settings of immunosuppression. Genes and Immunity (2005) The carbohydrate recognition domain of MBL binds to high mannose and N-acetyl-glucosamine oligosaccharides on various microorganisms, while the collagen-like domain is considered to bind to its receptors on phagocytes. 1,3 MBL activates complement independently of antibodies, which is a third pathway (lectin pathway) distinct from the classical and alternative complement activation cascade. It is therefore considered that MBL is an apical and important component of innate immunity of host defense. MBL has been shown to bind to a wide range of microorganisms including fungi, bacteria, protozoa, and viruses. 4 The serum level of MBL is dependent on various factors such as polymorphisms (in the coding region) and ethnicity and age (in the promoter region). [5][6][7] Of these factors, the structural polymorphisms at codons 52, 54, and 57 in the coding region are the most important determinants. All the three polymorphisms are caused by a single amino-acid substitution and result in the profound decrease of serum MBL in the individuals carrying the polymorphisms homozygously. Two polymorphisms in the promoter region at positions À550 and À221 also have additional, but less pronounced effects on the serum level of MBL. 5 Individuals carrying either of these three codon variants homozygously are common in different ethnic groups from 5 to 10%. 4 MBL deficiency is associated with infection in infants with immature immunity, 8,9 and patients with autoimmune disorders 10 and cystic fibrosis. 11,12 An association of MBL deficiency and infection is also reported in patients treated with conventional chemotherapy 13,14 or high-dose myeloablative chemotherapy followed by allogeneic stem cell transplantation, 15 which is not confirmed by others. 16,17 In the present study, we report an increased risk of major bacterial infection in patients carrying the MBL polymorphism when treated with high-dose chemotherapy (HDT) followed by autologous peripheral blood stem cell transplantation (auto-PBSCT). In ad...