Shiro Naoe

A novel immunosuppressant, FTY20, with a unique mechanism of action, induces long-term graft acceptance in rat and dog allostransplantation

A new compound with an immunosuppressive property was purified from culture filtrates of Isaria sinclairii and was chemically modified to FTY720. Rat spleen cells incubated with FTY720 demonstrated features characteristic of apoptosis--such as the absence of surface microvilli, chromatin condensation, and the formation of apoptotic bodies--by electron microscopy, and genemic DNA fragmentation by agarose gel electrophoresis. When FTY720 was administered in liver-allografted rats at a dose of 0.5 mg/kg from day 1 to day 14 after transplantation, the recipients survived significantly longer than the control group. Pretransplant treatment with 5 mg/kg of FTY720 one day before and on the day of grafting induced a remarkable prolongation of recipient survival, and three of 10 recipients survived for longer than 50 days. Furthermore, administration of FTY720 at 5 mg/kg on days 3 and day 4 after grafting also prolonged survival. In canine kidney allografting, a pretransplant 2-day course of FTY720 at 5 mg/kg prolonged graft survival. Daily administration of FTY720 in combination with CsA resulted in a significant prolongation of graft survival in a synergistic manner. In addition, FTY720 appeared to be nontoxic in canine recipients. These results demonstrated that FTY720, having a unique mechanism of action, induces long-term graft acceptance in rat and dog allotransplantation.

IgA Plasma Cell Infiltration of Proximal Respiratory Tract, Pancreas, Kidney, and Coronary Artery in Acute Kawasaki Disease

The etiology and pathogenesis of Kawasaki disease (KD) remain unknown. As previously reported, in US patients with acute KD, IgA plasma cells (PCs) infiltrate the vascular wall. To determine whether IgA PCs are increased at mucosal sites in KD and to determine whether other nonvascular KD tissues are infiltrated by IgA PCs, the cells were immunolocalized and quantitated in tissue sections taken from 18 US and Japanese patients who died of acute KD and from 10 age-matched controls. IgA PCs were significantly increased in the trachea of patients who died of acute KD, compared with controls (P<.01), a finding that was similar to findings in children with fatal respiratory viral infection. IgA PCs also infiltrated coronary artery, pancreas, and kidney in all KD patients. These findings strongly support entry of the KD etiologic agent through the upper respiratory tract, resulting in an IgA immune response, with systemic spread to vascular tissue, pancreas, and kidney.

Kawasaki Disease With Particular Emphasis on Arterial Lesions

Kawasaki disease (KD, or acute febrile mucocutaneous lymph node syndrome (MCLS)) was first described as a clinical entity in 1967 by Dr. Tomisaku Kawasaki of the Japan Red Cross Medical Center. Originally, it was thought to have a favorable prognosis, but as epidemiological surveys, augmented by pathological studies, have shown, it has come to be recognized as an often fatal disorder. In this report, the clinical symptoms, historical background, present status of research and epidemiological problems of KD are first described, and then we present a pathological and morphological outline of KD, focusing on pathological changes in the blood vessels, and the relationships of these changes to 1) the morphogenesis of arteritis, 2) the mechanism of coronary artery aneurysm formation and its sequelae, and 3) juvenile arteriosclerosis.

EPSTEIN-BARR VIRUS RELATED GASTRIC CANCER IN JAPAN : A MOLECULAR PATHO-EPIDEMIOLOGICAL STUDY

Epstein‐Barr virus (EBV) involvement in gastric carcinoma has been demonstrated by the presence of EBV genomes and EBV‐encoded small RNA (EBER) in the carcinoma cells, monoclonal proliferation of EBV‐infected carcinoma cells and elevated antibody titers. The present study was conducted to investigate the prevalence of EBV involvement among gastric carcinomas observed in nine Japanese cities with varying gastric cancer rates. In situ hybridization of EBER‐1 was applied to paraffin sections from 1848 carcinomas observed in 1795 cases and EBV involvement was detected based on uniform hybridization in carcinoma cells. Epstein‐Barr virus was detected in 6.6% of lesions and 6.7% of cases. The rate of EBV involvement did not vary significantly for each city and there was no correlation with underlying gastric cancer mortality rates. Thus, geographic variation of gastric cancer rates within Japan cannot be explained in terms of EBV involvement. Epstein‐Barr virus‐related gastric carcinoma is one of the most common EBV‐related tumors in Japan. The involvement of EBV was significantly more frequent among males than among females, mainly for cancers occurring in the upper and middle part of the stomach, and exhibited more variation by cell type among males. These observations suggest that other factors yet to be discovered may modulate the causal role of EBV in gastric carcinogenesis.

Neutrophilic involvement in the damage to coronary arteries in acute stage of Kawasaki disease

Abstract  Background : There has been no morphological evidence that polymorphonuclear leukocytes (PMNL) infiltrate the coronary arterial lesions of acute Kawasaki disease (KD) patients, although clinical data indicate the activation of PMNL.

PATHOLOGICAL STUDY OF SEQUELAE OF KAWASAKI DISEASE (MCLS): With Special Reference to the Heart and Coronary Arterial Lesions

Unexpected sudden cardiac death among children with a history of Kawasaki disease has come to be reported in Japan. Death occurred between 2 months and 8 years after complete recovery from Kawasaki disease according to our study material. To study the lesions of Kawasaki disease sequelae we examined 61 cases of Kawasaki disease which came to autopsy. In 17 of these the deaths apparently to be due to sequelae of this disease, were characterized by cardiac insufficiency caused by ancient coronary aneurysm with or?anized thrombotic occlusion and superimposed acute ischemic myocardial de?eneration and/or necrosis. The age of the lesions appears to correlate with the interval period between complete recovery from this disease and death. Six cases succumbed incidentally of other causes: one traffic accident, one hemophilus meningitis, one chronic myeloid leukemia, one neuroblastoma, one menin?eal hemorrha?e due to rupture of basilar arterial aneurysm, and one acute lymphatic leukemia. Even in these cases, definite sequelae of arteritis were detected. A surgically resected coronary aneurysm and a ventricular aneurysm were also examined. It was disclosed by mass physical check‐up of school children that 0.1% had a history of Kawasaki disease, among which 5‐6% showed cardiac and/or coronary abnormality includin? aneurysms. The high incidence of cardiac involvement in Kawasaki disease has been proved in this study and this kind of lesion has the possibility of resulting in unexpected cardiac death of children. ACTA PATHOL. JPN. 36: 1513‐1527, 1986.

The in vivo induction of lymphocyte apoptosis in MRL‐lpr/lpr mice treated with FTY720

The in vitro treatment of lpr thymocytes with FTY720 resulted in a dose‐dependent reduction in cell viability due to apoptosis. In order to study the effect of FTY720 in vivo, lpr mice received an oral daily dose of 1 mg/kg FTY720 for 14 days, beginning at 16 weeks of age which was when the animals were developing massive lymphoadenopathy. Compared with untreated lpr mice, FTY720‐treated lpr mice had significantly prolonged lives. At 24 weeks of age, treated mice demonstrated markedly reduced weights of the spleen and lymph nodes, and the proportion of CD3+B220+ and CD4−CD8− cells in the thymus, spleen and lymph nodes decreased markedly. In addition, in these mice the percentage of CD4+CD8+ and CD3−B220− cells in the thymus and the percentage of CD4+CD8−, CD4−CD8+, CD3+B220− and CD3−B220+ cells in the spleen returned to almost the normal values observed in wild‐type mice. Histological observation 1 day after the final administration of FTY720 revealed a remarkable infiltration of neutrophils in the lymphoid organs. Apoptotic cells were detected in all the lymphoid organs using in situ DNA nick‐end labelling. Electron microscopy showed that the apoptotic cells were ingested by phagocytes. FTY720 therapy is thus highly effective in Fas‐mutant animals with abnormally expanding lymphocytes.

Histopathological features of murine systemic vasculitis caused by Candida albicans extract--an animal model of Kawasaki disease.

AbstractObjective and Design: We examined the histopathological features of systemic vasculitis caused in mice by injection of a Candida albicans (C. albicans) extract and investigated the principal genetic roles in the development of vasculitis. Materials and Methods: C. albicans extract was injected intraperitoneally for five consecutive days in the 1st and 5th weeks to CD-1, C57BL/6N, C3H/HeN, BALB/cAnN, DBA/2N and CBA/JN mice. At week 8, mice were killed, and histological examination was performed by light microscopy. Results: Arteritis had developed in 66% of CD-1 mice. The extramural coronary arteries and aortic root close to the orifice of coronary arteries were most frequently involved. Histologically, the characteristic feature of the arteritis was proliferative and granulomatous inflammation accompanied by numerous macrophages, lymphocytes, plasma cells and neutrophils. Fibrocellular intimal thickening with destruction of the internal elastic lamina and media was also observed. Five mouse strains after injection of C. albicans extract were clearly classified into a resistant group (CBA/JN, DBA/2N and BALB/cAnN mice) and a sensitive group (C3H/HeN and C57BL/6N mice). The inbred mouse strains which showed the same histocompatibility-2 (H-2) haplotype exhibited a different susceptibility to development of vasculitis. Conclusion: This arteritis murine model shows unique histological features that have not been observed in other animal vasculitis models and it most closely resembles Kawasaki disease in humans. The genetic control of susceptibility to induction of vasculitis by the C. albicans extract is dependent to the mouse strains, but is not linked to the H-2 loci.

Interferon-gamma (IFN-γ)-dependent protection and synthesis of chemoattractants for mononuclear leucocytes caused by IL-12 in the lungs of mice infected with Cryptococcus neoformans

We have recently demonstrated that IL‐12 induced cellular inflammatory responses consisting mainly of accumulation of mononuclear leucocytes in the lungs of mice infected with Cryptococcus neoformans and protected mice against fulminant infection. We examined the involvement of endogenously synthesized IFN‐γ in such a response by investigating the effects of a neutralizing monoclonal antibody against this cytokine. The latter treatment completely abrogated the positive effects of IL‐12 on survival of infected mice and prevented IL‐12‐induced elimination of microbials from the lungs. Histopathological examination showed that accumulation of mononuclear leucocytes in the infected lungs caused by IL‐12 was clearly inhibited by anti‐IFN‐γ MoAb. We also examined the local production of mononuclear cell‐attracting chemokines such as monocyte chemotactic protein‐1 (MCP‐1), regulated upon activation, normal T cell expressed and secreted (RANTES), macrophage inflammatory protein‐1α (MIP‐1α), MIP‐1β and IFN‐γ‐inducible protein 10 (IP‐10) in the lungs using a reverse transcriptase‐polymerase chain reaction (RT‐PCR) method. We found that these chemokines were not synthesized in the infected lungs, while IL‐12 treatment markedly induced their production. Interestingly, neutralizing anti‐IFN‐γ MoAb strongly suppressed IL‐12‐induced production of these chemokines. Similar results were obtained with MCP‐1 and MIP‐1α when their synthesis was measured at the protein level using respective ELISA kits. Our results indicate that IFN‐γ plays a central role in the protective effects of IL‐12 by inducing mononuclear leucocyte‐attracting chemokines and cellular inflammatory responses.

Induction of coronary arteritis with administration of CAWS (Candida albicans water-soluble fraction) depending on mouse strains

The intraperitoneal administration of CAWS (water‐soluble extracellular polysaccharide fraction obtained from the culture supernatant of Candida albicans) to mice induces coronaritis similar to Kawasaki disease. We analyzed differences in the production of cytokines involved in the occurrence of coronary arteritis among mouse strains, C3H/HeN, C57BL/6, DBA/2 and CBA/J that were injected with CAWS at 4 mg/mouse for 5 consecutive days in the first week and the fifth week of administration. The incidence of arteritis was 100% in C57BL/6, C3H/HeN and DBA/2 mice, but only 10% in CBA/J mice. The coronary arteritis observed in DBA/2 mice was the most serious, with several mice expiring during the observation period. The CAWS‐sensitive strains revealed increased levels of IL‐6 and IFN‐γ during the course of a specific response to CAWS by spleen cells. In contrast, IL‐10 levels were observed to increase markedly in CAWS‐resistant CBA/J mice, but not the CAWS‐sensitive strains. However, TNF‐α levels were more elevated only in DBA/2 mice. The difference in disease development and cytokine production strongly suggests that the genetic background of the immune response to CAWS contributes to the occurrence of coronary arteritis.