Depletion and impaired interferon-alpha-producing capacity of blood plasmacytoid dendritic cells in human T-cell leukaemia virus type I-infected individuals

Dendritic cells (DCs) play an important role in innate and adaptive immunity. There are two major populations of blood DCs, myeloid DCs (myDCs) and plasmacytoid DCs (pcDCs). pcDCs are particularly important in antiviral as well as in general host defence, as they are the principal producers of type I interferons (IFNs). In this study, we analysed myDCs and pcDCs in healthy controls, human T-cell leukaemia virus type I (HTLV-I)-infected asymptomatic carriers (ACs), and patients with adult T-cell leukaemia (ATL). ATL patients had significantly decreased number of pcDCs and myDCs compared with controls. IFN-alpha production by peripheral blood mononuclear cells (PBMCs) was markedly reduced in ATL patients. Purified pcDCs from ACs were found to have impaired IFN-alpha-producing capacity, suggesting a functional defect in pcDCs in HTLV-I-infected individuals. Interestingly, pcDCs were shown to be susceptible to HTLV-I infection. Thus, impaired IFN-alpha production by pcDCs may contribute to the immunodeficiency observed in ATL. Furthermore, IFN-alpha-producing capacity was inversely correlated with HTLV-I proviral load in PBMCs from ACs, suggesting a role for pcDCs in maintaining the carrier state. Taken together, we hypothesize that the depletion and impaired IFN-alpha-producing capacity of blood DCs may contribute to the immunodeficiency in ATL and/or the development of ATL.     

GPI transamidase of Trypanosoma brucei has two previously uncharacterized (trypanosomatid transamidase 1 and 2) and three common subunits

Glycosylphosphatidylinositol (GPI) anchor is a membrane attachment mechanism for cell surface proteins widely used in eukaryotes. GPIs are added to proteins posttranslationally by a complex enzyme, GPI transamidase. Previous studies have shown that human and Saccharomyces cerevisiae GPI transamidases are similar and consist of five homologous components: GAA1, GPI8, PIG-S, PIG-T, and PIG-U in humans and Gaa1p, Gpi8p, Gpi17p, Gpi16p, and Cdc91p in S. cerevisiae. We report that GPI transamidase of Trypanosoma brucei (Tb), a causative agent of African sleeping sickness, shares only three components (TbGAA1, TbGPI8, and TbGPI16) with humans and S. cerevisiae but has two other specific components, trypanosomatid transamidase 1 (TTA1) and TTA2. GPI transamidases of both bloodstream form (growing in mammalian blood) and procyclic form (growing in tsetse fly vector) of the parasite have the same five components. Homologues of TTA1 and TTA2 are present in Leishmania and Trypanosoma cruzi but not in mammals, yeasts, flies, nematodes, plants, or malaria parasites, suggesting that these components may play unique roles in attachment of GPI anchors in trypanosomatid parasites and provide good targets for antitrypanosome drugs.     

Case of B-Cell Lymphoma with Rearrangement of the <Emphasis Type="Italic">BCL1, BCL2, BCL6</Emphasis>, and <Emphasis Type="Italic">c-MYC</Emphasis> Genes

We managed a peculiar case of lymphoma showing immunohistochemical overexpression of cyclin D1. At initial examination the patient had meningeal lymphomatosis and general lymphadenopathy. Histologic examination of biopsy specimens of inguinal lymph nodes showed tumor cells and vague nodular growth resembling lymphoblasts. The results of flow cytometric analysis were positive for CD10, CD20, CD103, and immunoglobulin G (IgG) and Ig kappa and were negative for CD5, CD23, and terminal deoxynucleotidyl transferase activity. Results of immunohistochemical analysis of paraffin-embedded specimens were positive for cyclin D1 and Bcl2 in the tumor cells. Sixty percent of tumor cells had positive results for MIB1/Ki67. Cytogenetic and molecular studies revealed tumor cells simultaneously had t(14;18)(q32;q21), t(11;22)(q13;q11), t(8;14)(q24;q32), and t(3;14)(q27;q32) with the rearrangement of BCL1, BCL2, BCL6, and c-MYC genes. Lymphadenopathy showed a quick and complete response to doxorubicin-containing systemic chemotherapy with rituximab, but the central nervous system disease progressed and killed the patient.     

A Novel Chromosomal Abnormality,t(6;10)(q27;q22), Found in a Polycythemic Potential Donor for Allogeneic Hematopoietic Stem Cell Transplantation

A 59-year-old man was a potential donor for allogeneic hematopoietic stem cell transplantation and was found to be healthy but slightly polycythemic. The bone marrow was morphologically normal, but karyotyping of bone marrow cells showed t(6;10)(q27;q22) in 7 of 20 metaphases analyzed by G-banding and only the t(6;10) abnormality in 3 of 5 metaphases analyzed by the spectral karyotyping method. G-banding analysis of peripheral blood mononuclear cells cultured with phytohemagglutinin for 72 hours showed a normal karyotype in all 20 metaphases analyzed.These findings suggest clonal expansion with t(6;10)(q27;q22) in the bone marrow of this individual. He was determined to be ineligible for donation. A coordinated nationwide work-up for older donors is necessary to ensure high-quality standards.     

Persistence and Epidemic Propagation of a Pseudomonas aeruginosa Sequence Type 235 Clone Harboring an IS26 Composite Transposon Carrying the blaIMP-1 Integron in Hiroshima,Japan, 2005 to 2012

A 9-year surveillance for multidrug-resistant (MDR) Pseudomonas aeruginosa in the Hiroshima region showed that the number of isolates harboring the metallo-β-lactamase gene bla_IMP-1 abruptly increased after 2004, recorded the highest peak in 2006, and showed a tendency to decline afterwards, indicating a history of an epidemic. PCR mapping of the variable regions of the integrons showed that this epidemic was caused by the clonal persistence and propagation of an MDR P. aeruginosa strain harboring the bla_IMP-1 gene and an aminoglycoside 6′-N-acetyltransferase gene, aac(6′)-Iae in a class I integron (In113), whose integrase gene intl1 was disrupted by an IS26 insertion. Sequence analysis of the representative strain PA058447 resistance element containing the In113-derived gene cassette array showed that the element forms an IS26 transposon embedded in the chromosome. It has a Tn21 backbone and is composed of two segments sandwiched by three IS26s. In Japan, clonal nationwide expansion of an MDR P. aeruginosa NCGM2.S1 harboring chromosomally encoded In113 with intact intl1 is reported. Multilocus sequence typing and genomic comparison strongly suggest that PA058447 and NCGM2.S1 belong to the same clonal lineage. Moreover, the structures of the resistance element in the two strains are very similar, but the sites of insertion into the chromosome are different. Based on tagging information of the IS26 present in both resistance elements, we suggest that the MDR P. aeruginosa clone causing the epidemic in Hiroshima for the past 9 years originated from a common ancestor genome of PA058447 and NCGM2.S1 through an IS26 insertion into intl1 of In113 and through IS26-mediated genomic rearrangements.     

Progression of cervical instabilities in patients with rheumatoid arthritis 5.7?years after their first lower limb arthroplasty

We reviewed 101 rheumatoid arthritis (RA) patients who had undergone their first lower limb arthroplasty between 1990 and 2002. None of the patients had received immunosuppressant or biological drugs. Preoperative and follow-up cervical spine radiographs had been performed (more than 2?years after the arthroplasty). Cervical spine instabilities were found in 62 and 82 patients, and a posterior atlantodental interval (PADI) of <14?mm was present in 20 and 22 patients in the respective radiographs. The presence of cervical spine instabilities and PADI <14?mm were correlated with a higher modified Lansbury index (LI) both preoperatively and at final follow-up. Patients with no cervical spine instability throughout the follow-up had a lower average LI. Patients with atlantoaxial subluxation (AAS), vertical subluxation (VS), and subaxial subluxation (SAS) had more joint arthroplasties at final follow-up compared with other patients. The percentage of patients with single and multiple cervical instabilities increased at final follow-up. The incidence of cervical spine instabilities in RA patients requiring a lower limb arthroplasty is extremely high, with progression of these instabilities after the procedure. There is a correlation between the severity of RA activity in peripheral joints and the severity of cervical spine instabilities.     

Nonsteroidal anti-inflammatory drugs potentiate 1-methyl-4-phenylpyridinium (MPP+)-induced cell death by promoting the intracellular accumulation of MPP+ in PC12 cells

In this study, we investigated the effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on 1-methyl-4-phenylpyridinium (MPP(+))-induced cell death in PC12 cells. Coincubation of PC12 cells with indomethacin, ibuprofen, ketoprofen, or diclofenac, but not aspirin or N-[2-(cyclohexyloxy)-4-nitrophenyl]methanosulfonamide (NS-398), significantly potentiated the MPP(+)-induced cell death. In contrast, these NSAIDs had no effect on rotenone-induced cell death. The potentiating actions of these NSAIDs were not suppressed by treatment with phenyl-N-butyl-nitrone, a radical scavenger; N-acetyl-l-cysteine, an antioxidant; Ac-DEVD-CHO, a selective caspase-3 inhibitor; or 2-chloro-5-nitro-N-phenylbenzamide (GW9662), a selective antagonist of peroxisome proliferator-activated receptor gamma. Furthermore, we observed that DNA fragmentation, which is one of the hallmarks of apoptosis, was not induced by coincubation with MPP(+) and NSAIDs. We confirmed that coincubation of PC12 cells with 30 microM MPP(+) and 100 microM indomethacin, ibuprofen, ketoprofen, or diclofenac led to a significant increase in the accumulation of intracellular MPP(+) compared with incubation with 30 microM MPP(+) alone. In addition, these NSAIDs markedly reduced the efflux of MPP(+) from PC12 cells. (3-(3-(2-(7-Chloro-2-quinolinyl) ethenyl) phenyl ((3-dimethyl amino-3oxo-propyl) thio) methyl) propanoic acid (MK 571), which is an inhibitor of multidrug resistance proteins (MRPs), mimicked the NSAIDs-induced effects, increasing cell toxicity and promoting the accumulation of MPP(+). Moreover, some types of MRPs' mRNA were detected in PC12 cells. These results suggest that some NSAIDs might cause a significant increase in the intracellular accumulation of MPP(+) via the suppression of reverse transport by the blockade of MRP, resulting in the potentiation of MPP(+)-induced cell death.     

Disappearance of CD 20 after treatment with rituximab of mantle cell lymphoma

A 60-year-old female visited our hospital in May 2001 because of systemic lymphadenopathy. Her white blood cell count was 25,510/microliters with 93% of lymphocytes. Bone marrow aspiration revealed that 86% of nucleated cells were lymphocytes. Lymphocytes in the peripheral blood and bone marrow were positive for CD 5, 19, 20, and sIgx and negative for CD 23. FISH analysis detected the chimeric bcl 1/IgH fusion gene. Immunohistochemistry of a biopsied lymph node revealed that lymphoma cells were positive for cyclin D 1. Mantle cell lymphoma (MCL) was diagnosed at clinical stage IV A. Although a partial remission was obtained after CHOP plus rituximab therapy, the patient's disease recurred in March 2002 and she died in spite of salvage therapy including rituximab. Immunohistochemistry of the bone marrow cells after salvage rituximab therapy revealed that lymphoma cells were still positive for CD 5 and cyclin D 1, but negative for CD 20 and sIgx. We could not exactly determine how frequently CD 20 expression becomes negative in B-cell lymphomas after treatment with rituximab. We found only two reported cases that suggested rituximab down-regulated CD 20 expression in MCL. We herein describe a case of MCL with very notable clinical features.