Masami Takei

A conserved idiotype and antibodies to retroviral proteins in systemic lupus erythematosus.

22 of 61 systemic lupus erythematosus (SLE) patients produced antibodies to the p24 gag protein of HIV-1 demonstrated by Western blotting. 20 of these 22 patients (91%) also express the 4B4 idiotype (Id 4B4) previously identified on a human anti-Sm monoclonal antibody called 4B4. This represents an enrichment for this Id (seen in only 52% of SLE patients generally). Eight of these 22 SLE patients also have anti-Sm antibody activity. Sm partially inhibits the antibody binding of p24 gag suggesting immunologic cross-reactivity between the retroviral antigen p24 gag and the autoantigen Sm. Anti-Id 4B4 also inhibits p24 gag antibody binding by as much as 40%. Finally the monoclonal antibody 4B4 showed cross-reactivity to Sm and p24 gag. The following points emerge from our studies: (a) SLE patients make antibodies to p24 gag of HIV-1, (b) there is a relationship between immunity to p24 gag and a conserved idiotype, and (c) anti-Sm antibodies can cross-react with p24 gag.

Epstein-Barr Virus Induces Erosive Arthritis in Humanized Mice

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of rheumatoid arthritis (RA) on the basis of indirect evidence, such as its presence in affected joint tissues, antigenic cross reactions between EBV and human proteins, and elevated humoral and cellular anti-EBV immune responses in patients. Here we report development of erosive arthritis closely resembling RA in humanized mice inoculated with EBV. Human immune system components were reconstituted in mice of the NOD/Shi-scid/IL-2Rγnull (NOG) strain by transplantation with CD34+ hematopoietic stem cells isolated from cord blood. These humanized mice were then inoculated with EBV and examined pathologically for the signs of arthritis. Erosive arthritis accompanied by synovial membrane proliferation, pannus formation, and bone marrow edema developed in fifteen of twenty-three NOG mice transplanted with human HSC and inoculated with EBV, but not in the nine NOG mice that were transplanted with HSC but not inoculated with EBV. This is the first report of an animal model of EBV-induced arthritis and strongly suggest a causative role of the virus in RA.

Increased soluble CD4 and decreased soluble CD8 molecules in patients with Sjögren's syndrome

PURPOSE A new enzyme-linked immunosorbent assay for soluble CD4 (sCD4) and soluble CD8 (sCD8) molecules has been developed. We estimated the concentrations of these molecules in patients with Sjögrens syndrome and in patients with systemic lupus erythematosus (SLE) serving as a control population for non-Sjögrens inflammatory disease, since several findings suggestive of an aberration of immunocompetent cells have been reported in these autoimmune diseases. PATIENTS AND METHODS The study population consisted of 41 patients with Sjögrens syndrome (28 cases of the primary form and 13 cases of the secondary form), 66 patients with SLE, and 43 normal individuals. Serum samples and clinical and laboratory data were collected from each patient and control. Assays of the sCD4 and sCD8 molecules were performed using an enzyme-linked immunosorbent kit developed by T Cell Science Inc., Cambridge, MA. RESULTS The concentration of sCD4 was significantly increased in patients with both primary and secondary Sjögrens syndrome as compared with that in the control subjects. In contrast, sCD8 was significantly decreased in patients with primary disease but not in patients with secondary disease. A low or high concentration of sCD8 was significantly correlated with the presence of anti-SS-A antibody or hypocomplementemia, respectively. A similar significant correlation was noted between an increased sCD4 concentration and increased serum IgG level. In patients with SLE, the levels of both sCD4 and sCD8 were significantly increased. CONCLUSION These observations represent the first evidence of an increased level of the sCD4 molecule and a decreased level of the sCD8 molecule and an association with immunologic abnormalities in Sjögrens syndrome. The increased and decreased levels of these soluble molecules observed may play a pathologic role in patients with Sjögrens syndrome.

Antiproteinuric Effect of Angiotensinconverting Enzyme Inhibitors and an Angiotensin II Receptor Blocker in Patients with Lupus Nephritis

Although the effects of angiotensin II receptor blockers (ARBs) on non-diabetic glomerulonephritis have been reported, studies of their effects on collagenvascular diseases, particularly lupus nephritis, are limited. In this retrospective, observational study, systemic lupus erythematosus (SLE) patients (n = 7) with lupus nephritis and uncontrolled proteinuria were treated with an angiotensin-converting enzyme inhibitor followed by the ARB losartan (25–50 mg/day). Urinary protein excretion and renal function were evaluated. After 12 months of losartan, mean urinary protein excretion decreased significantly by 84.8%. Mean systolic and diastolic blood pressures also decreased significantly during the 12 months of losartan treatment, although not in normotensive patients. Complement 4, total complement activity and anti-dsDNA antibody levels, which are indices of SLE activity, and serum creatinine levels, which is an index of renal function, showed no change in response to losartan treatment. A more extensive evaluation of the effects of ARBs in patients with lupus nephritis and poorly controlled proteinuria is required.

Identification of candidate genes for Sjögren's syndrome using MRL/lpr mouse model of Sjögren's syndrome and cDNA microarray analysis

Sjögrens syndrome is a chronic autoimmune disease characterized by focal lymphocytic infiltration of lacrimal and salivary glands, but the precise mechanism of this syndrome is poorly understood. To clarify the mechanism of onset and progression of Sjögrens syndrome, it is necessary to identify Sjögrens syndrome-related genes. For this purpose, we used MLR/MpJ-lpr/lpr (MRL/lpr) mouse as a model of human secondary Sjögrens syndrome and analyzed specific mRNA expression pattern in MRL/lpr mouse salivary glands by in-house cDNA microarray. Among arrayed 2304 genes, 13 genes were isolated as highly expressed genes in MRL/lpr mouse salivary gland in comparison with MRL/MpJ-+/+ (MRL/+) mouse tissue. Subsequently, we performed RT-PCR analysis and confirmed the high expression level of nine genes; caspase3, Ly-6C.2, vimentin, Mel-14 antigen, cathepsin B, mpt1, Laptm5, Gnai2 and UCP2. Five of the nine genes have already been identified in patients with Sjögrens syndrome or mice models of the syndrome, but the remaining four genes; mpt1, Laptm5, Gnai2, and UCP2 have not been reported previously as Sjögrens syndrome-related genes. Although, further experiments are necessary to examine the relationship between these four genes and Sjögrens syndrome, our system of mouse model of Sjögrens syndrome combined with in-house cDNA microarray is suitable for the isolation of Sjögrens syndrome-related genes.

Modeling EBV infection and pathogenesis in new-generation humanized mice

The development of highly immunodeficient mouse strains has allowed the reconstitution of functional human immune system components in mice. New-generation humanized mice generated in this manner have been extensively used for modeling viral infections that are exclusively human tropic. Epstein–Barr virus (EBV)-infected humanized mice reproduce cardinal features of EBV-associated B-cell lymphoproliferative disease and EBV-associated hemophagocytic lymphohistiocytosis (HLH). Erosive arthritis morphologically resembling rheumatoid arthritis (RA) has also been recapitulated in these mice. Low-dose EBV infection of humanized mice results in asymptomatic, persistent infection. Innate immune responses involving natural killer cells, EBV-specific adaptive T-cell responses restricted by human major histocompatibility and EBV-specific antibody responses are also elicited in humanized mice. EBV-associated T-/natural killer cell lymphoproliferative disease, by contrast, can be reproduced in a distinct mouse xenograft model. In this review, recent findings on the recapitulation of human EBV infection and pathogenesis in these mouse models, as well as their application to preclinical studies of experimental anti-EBV therapies, are described.

Tocilizumab Treatment Increases Left Ventricular Ejection Fraction and Decreases Left Ventricular Mass Index in Patients with Rheumatoid Arthritis without Cardiac Symptoms: Assessed Using 3.0 Tesla Cardiac Magnetic Resonance Imaging

Objective. The aim of our pilot study was to prospectively evaluate the effect of inhibiting interleukin 6 on the left ventricular (LV) structure and function in patients with rheumatoid arthritis (RA) without cardiac symptoms, using cardiac magnetic resonance (CMR). Methods. Female patients with RA with active disease and healthy controls were enrolled. Cardiac symptoms were absent in all subjects. Tocilizumab (TCZ; 8 mg/kg IV every 4 weeks) was prescribed for patients with RA with an inadequate clinical response to methotrexate. All subjects underwent baseline evaluation of LV function and structure measured by CMR. We compared measures of LV geometry and function between patients with RA and patients without RA controls at baseline, and changes in the same variables between baseline and after 52 weeks of treatment among the group with RA. Results. Twenty women with RA were compared with 20 women without RA of similar mean age. In patients with RA at baseline, ejection fraction (EF) was significantly lower (−3.7%) and LV mass index (LVMI) significantly higher (+9.2%) compared with controls. TCZ treatment resulted in a significant decrease in the Simplified Disease Activity Index (SDAI) after 52 weeks of treatment, paralleling a significant increase in EF (+8.2%) and a significant decrease in LVMI (−24.4%) over the same period. The percentage change in LVMI correlated strongly with the percentage change in SDAI (r = −0.63, p = 0.0028). LV geometry in the group with RA at baseline showed eccentric hyper-trophy compared with the group without RA, a condition that normalized after TCZ treatment. Conclusion. TCZ treatment significantly increased EF and decreased LVMI associated with disease activity.

Early bone marrow hematopoietic defect in simian/human immunodeficiency virus C2/1-infected macaques and relevance to advance of disease.

ABSTRACT To clarify hematological abnormalities following infection with human immunodeficiency virus (HIV), we examined the hematopoietic capability of bone marrow by using cynomolgus monkeys infected with pathogenic simian/human immunodeficiency virus (SHIV) strain C2/1, an animal model of HIV infection. The relationship between the progress of the infection and the CD4/CD8 ratio of T lymphocytes or the amount of SHIV C2/1 viral load in the peripheral blood was also investigated. A colony assay was performed to assess the hematopoietic capability of bone marrow stem cells during the early and advanced phases of the infection. Colonies of granulocytes-macrophages (GM) were examined by PCR for the presence of the SIVmac239 gag region to reveal direct viral infection. There was a remarkable decrease in the CFU-GM growth on days 1 and 3 postinoculation, followed by recovery on day 56. During the more advanced stage, the CFU-GM growth decreased again. There was minimal evidence of direct viral infection of pooled cultured CFU-GM despite the continuously low CD4/CD8 ratios. These results indicate that the decrease in colony formation by bone marrow stem cells is reversible and fluctuates with the advance of the disease. This decrease was not due to direct viral infection of CFU-GM. Our data may support the concept that, in the early phase, production of inhibitory factors or deficiency of a stimulatory cytokine is responsible for some of the bone marrow defects described in the SHIV C2/1 model.

Antithymocyte Globulin for a Patient with Systemic Lupus Erythematosus Complicated by Severe Pancytopenia

The clinical use of antithymocyte globulin is rarely reported in patients with rheumatic diseases. We describe the use of this agent in a patient with systemic lupus erythematosus who concomitantly developed severe pancytopenia. High-dose methylprednisolone therapy had been unsuccessful in controlling either the disease exacerbation or the pancytopenia. Antithymocyte globulin and cyclosporin A were therefore administered to achieve immunosuppression. The exacerbation of disease activity was gradually lessened, except for persistent thrombocytopenia and anaemia. Severe and persistent immunosuppression, however, led to a fatal brain abscess. The combined use of both antithymocyte globulin and cyclosporin A induced potent immunosuppression, and should be confined to selected patients with systemic lupus erythematosus, and administered under detailed monitoring.

Induced Differentiation of Human Myeloid Leukemia Cells into M2 Macrophages by Combined Treatment with Retinoic Acid and 1α,25-Dihydroxyvitamin D3

Retinoids and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) induce differentiation of myeloid leukemia cells into granulocyte and macrophage lineages, respectively. All-trans retinoic acid (ATRA), which is effective in the treatment of acute promyelocytic leukemia, can induce differentiation of other types of myeloid leukemia cells, and combined treatment with retinoid and 1,25(OH)2D3 effectively enhances the differentiation of leukemia cells into macrophage-like cells. Recent work has classified macrophages into M1 and M2 types. In this study, we investigated the effect of combined treatment with retinoid and 1,25(OH)2D3 on differentiation of myeloid leukemia THP-1 and HL60 cells. 9-cis Retinoic acid (9cRA) plus 1,25(OH)2D3 inhibited proliferation of THP-1 and HL60 cells and increased myeloid differentiation markers including nitroblue tetrazolium reducing activity and expression of CD14 and CD11b. ATRA and the synthetic retinoic acid receptor agonist Am80 exhibited similar effects in combination with 1,25(OH)2D3 but less effectively than 9cRA, while the retinoid X receptor agonist HX630 was not effective. 9cRA plus 1,25(OH)2D3 effectively increased expression of M2 macrophage marker genes, such as CD163, ARG1 and IL10, increased surface CD163 expression, and induced interleukin-10 secretion in myeloid leukemia cells, while 9cRA alone had weaker effects on these phenotypes and 1,25(OH)2D3 was not effective. Taken together, our results demonstrate selective induction of M2 macrophage markers in human myeloid leukemia cells by combined treatment with 9cRA and 1,25(OH)2D3.