Yujiro Fujino

Recruitment of antigen-nonspecific cells plays a pivotal role in the pathogenesis of a T cell-mediated organ-specific autoimmune uveoretinitis

Abstract Experimental autoimmune uveoritinitis (EAU) is a protitypic T cell-mediated autoimmune disease, whose target tissue is the nueral retina, that is used as a model for a number of human blinding ocular diseases of a presumed autoimmune nature. EAU in rats can be induced by adoptive transfer of small numbers of retinal antigen-specific CD4+ T cell lines. Although recruitment mechanisms were assumed to play a role in the immunopathogenesis of uveitis, there is no direct evidence that would permit assessment of the importance of recruited non-antigen-specific T cells in retinal autoimmunity. In the present study, we addressed this question by using congenitally athymic Lewis rats (LEW.rnu/rnu), that are deficient in functional endogenous T cells, but are otherwise syngeneic with the euthymic Lewis rats that develop characteristically severe EAU. The uveitogenic stimulus was delivered in the form of phenotypically and functionally homogeneous pathogenic T cell lines, specific to the major pathogenic epitope of either the intracellular photoreceptor protein, S-Ag or the extracellular photoreceptor matriz protein, IRBP. Depending on the T cell line used, EAU in athymic rats was either drastically reduced in severity (IRBP), or essentially absent (S-AG). Susceptibility was restored when the athymic animals were reconstituted with immunocompetent T cells from the syngeneic authymic donors. While the intraocular infiltrate in euthymic rats was predominantly lymphocytic, with smaller numbers of monocyte/macrophages and even fewer neutrophils, the sparse infiltrate in athymics was largely monocytic, and with a relatively high proportion of neutrophils and eosinophils. Reconstituted animals had an intermediate histological picture with respect to the infiltrating cell types and disease severity. Our data are consistent with the interpretation that recruitment of naive T cells constitutes an amplification mechanism that is central to the expression and pathogenesis of uveitis. The extent of dependence on this phenomenon appears to be influenced by the antigenic specificity of the T cell line, and could be connected to the ‘accessibility’ of the target antigen in vivo.

Behcet's Disease Associated With one of the HLA-B51 Subantigens, HLA-B* 5101

The strong association of Behçets disease with HLA-B51 in several ethnic groups is well known. Because the HLA-B51 antigen has been recently identified to comprise three alleles, HLA-B* 5101, HLA-B* 5102, and HLA-B* 5103, we sought to investigate whether there is any correlation of one particular allele among them with B51-positive patients with Behçets disease. Forty-six Japanese patients with Behçets disease and HLA-B51 were typed by using the alloantisera, which allowed the subdivision of B51 antigen by the microlymphocyte toxicity assay. All the patients were found to carry HLA-B* 5101. This result suggests that amino acid substitutions at residue 167 or 171 prevent the development of Behçets disease, because HLA-B* 5101 differs from HLA-B* 5102 and HLA-B* 5103 by single amino acid substitution at residues 171 and 167, respectively, or that another non-HLA gene tightly linked to the HLA-B* 5101-associated haplotype around the HLA class I gene region is responsible for the susceptibility to Bechçets disease. This study provides insight into the molecular mechanism underlying an HLA association with Behçets disease.

Epidemiological Features and Visual Prognosis of Behçet's Disease ☆

PURPOSE Retrospective evaluation of epidemiological features and visual prognosis of patients with Behçets disease (BD) who visited the University of Tokyo Hospital between 1974 and 1993. OBSERVATIONS During the survey period, more than 100 new patients with BD visited the uveitis clinic in each 5-year period. The number of new patients decreased in the most recent 5-year period from 1989 to 1993. Although BD has always been more prevalent in men, the percentage of women has increased to 24.7% (19/77) in the most recent 5-year survey period. The percentage of patients who initially manifested ocular symptoms in their third or fourth decade was more than 70%. The proportion of the incomplete type of BD gradually had increased to 62.3% (48/77) by 1993. Among the extraocular major symptoms, oral aphtha and skin lesions have been frequent and genital ulcer has become less frequent in the last 20 years. The patients whose visual acuity was better than 0.4 at the first visit in the 1984-1993 period had a significantly better visual prognosis than the patients in the previous 10-year period. The main drug therapy consisted of colchicine and cyclophosphamide in the earlier 10-year period, and of colchicine and ciclosporin in the later 10-year period. CONCLUSIONS Behçets disease is still one of the most frequently encountered types of endogenous uveitis. There have been some changes in the epidemiological features of the patients with BD over the past 20 years. The introduction of ciclosporin in 1985 is probably responsible for the improvement of the visual prognosis in BD patients.

Plasma and whole-blood chemokine levels in patients with Behcet's disease

BackgroundChemokines are a family of chemoattractants of leukocytes that play a critical role for leukocyte recruitment in various inflammatory diseases. The purpose of this study is to investigate the involvement of chemokines, interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) in the peripheral blood, with a special reference to disease activities of the patients with Behçets disease (BD).MethodsThe study population consisted of totally 55 patients with BD who had panuveitis (20 patients with active BD, 35 patients with inactive BD) as well as 19 healthy volunteers as control. Disease activity was defined according to the existence of ocular inflammation. IL-8 and MCP-1 concentration levels in the plasma and whole-blood samples were measured by enzyme-linked immunosorbent assay. Whole-blood samples were obtained by lysing cell membranes of peripheral blood cells.ResultsMost of the plasma IL-8 samples were below the detectable limit. Whole-blood IL-8 levels were readily measured. The levels in the patients with active BD were significantly higher than the other two groups. The patients with active and inactive BD showed higher plasma and whole-blood levels of MCP-1 than controls. The plasma and whole-blood MCP-1 levels of the samples collected at the same time showed a linear correlation.ConclusionA close relationship was found to exist between the cell-associated IL-8 and the disease activity, while a persistent role of MCP-1 was observed in BD. Measuring the whole-blood levels of chemokines is useful for monitoring the disease activity.

FK506 treatment of S-antigen induced uveitis in primates

FK506 is a new immunosuppressive agent which has been found more potent than cyclosporine based on the dosage. FK506 was examined here for its effect on the development of uveitis in primates immunized with S-antigen. FK506 successfully inhibited uveitis in monkeys, even when administered three weeks after the first immunization, at the time when the immunopathogenic mechanism of uveitis is assumed to be developed. All four monkeys injected with 0.5 mg/kg/day of FK506 did not develop uveitis, 2 out of 4 treated with the 0.25 mg and 3 out of 4 of those receiving the 0.125 mg also did not develop disease. FK506 suppressed to some extent the cellular and humoral immune responses to S-antigen. The main side effect of FK506 was weight loss. We consider that this drug may be considered as a new potential therapeutic agent for immune-mediated ocular disease in humans.

Association between mast cells and the development of experimental autoimmune uveitis in different rat strains

To study the role of anterior uveal mast cells in experimental autoimmune uveitis (EAU), the mast cells in the iris and ciliary body of Lewis rats, Brown Norway (BN) rats, and their F1 hybrids (LBNF1) were quantitated in normal rats and during the induction period of EAU. The mean baseline mast cell number was 68.9 +/- 10.8 per anterior uvea for Lewis rats, 0.3 +/- 0.2 for BN rats, and 4.6 +/- 0.6 for LBNF1 rats. Detectable mast cells in the anterior uvea of S-Ag-immunized Lewis rats decreased to 60% of control at 6 days postimmunization, recovered to 80% at 10 days, and dropped again to 16% at 13 days, with disease onset around 14 days. In Lewis rats that were adoptively transferred with a uveitogenic T-lymphocyte line, a profound drop in anterior uveal mast cell numbers occurred in the eyes with early signs of EAU, 3 days after the transfer. The decrease in detectable mast cells is consistent with mast cell degranulation. The data suggest that anterior mast cells participate in the immunopathogenesis of EAU and may influence the genetic susceptibility to EAU.

Two cases of frosted branch angiitis with central retinal vein occlusion.

BACKGROUND Frosted branch angiitis usually occurs in children, and has a good prognosis. We report two cases of unilateral frosted branch angiitis in adults. Both had poor visual outcomes because of associated central retinal vein occlusion and neovascular glaucoma. CASES Case 1 was a 36-year-old woman. Almost all retinal veins and some retinal arteries showed vasculitis in her right eye, and veins were slightly dilated and sheathed. Case 2 was a 23-year-old woman. Angle hypopyon was observed in her left eye. Retinal veins were dilated, meandering, and sheathed. Retinal hemorrhages were also observed. In both cases, after systemic steroid therapy the retinal vasculitis gradually decreased, but central retinal vein occlusions gradually developed. Despite systemic administration of urokinase and panretinal photocoagulation, neovascular glaucoma developed, and visual acuity diminished in both cases. CONCLUSIONS Two cases of frosted branch angiitis complicated by retinal vein occlusion are reported. Careful observation of retinal blood flow is necessary in frosted branch angiitis in adults.

Immunopathology of Experimental Autoimmune Uveoretinitis in Primates

The eyes and pineal glands from 10 monkeys immunized with S-antigen were studied using routine histopathological and immunohistochemical techniques. Seven out of 10 animals developed uveitis between 19 and 33 days after the initial immunization. Histopathology of the eyes harvested 70 days after immunization showed moderate to marked uveoretinitis, subretinal fibrosis, retinal necrosis and gliosis. The pineal glands demonstrated chronic pinealitis. The infiltrating cells were both CD3 and CD19/CD22 lymphocytes with a ratio of 1.4 in the eye and 2.2 in the pineal gland. The ratio of CD4 to CD8 lymphocytes was 1.5:1. MHC Class II antigens and adhesion molecule (ICAM-1) were observed on resident cells. The influx of B lymphocytes and the formation of subretinal fibrosis differentiate the disease in the monkey from that in the rat and mouse. These findings are similar to Vogt-Koyanagi-Harada syndrome and subretinal fibrosis with uveitis syndrome in human.

Statistical Analysis of Endogenous Uveitis at Tokyo University Hospital (1998-2000)

eye drops was 0.2 ± 0.6, at 1 month after switching (P < 0.0001).At 1 month after switching, 50 patients (89.3%) preferred brinzolamide. Adverse events are shown in Table 1. Eleven patients were excluded from the evaluation of hypotensive effects; eight could not continue brinzolamide treatment owing to adverse events, and three patients had not come to our hospital during the 6-month study for nonmedical reasons. There were no statistically significant differences in the IOP before or after switching (Table 2).

Experimental Uveitis Induced by Intravitreal or Intravenous Lipoteichoic Acid in Rabbits

PURPOSE To investigate the role of lipoteichoic acid (LTA), one of the cell wall components in gram-positive bacteria in uveitis. METHODS Intraocular inflammation in rabbit eyes was induced by intravitreal or intravenous injections of LTA from Staphylococcus aureus or Streptococcus sanguis. The inflammation was monitored progressively with the laser flare-cell photometer, and examined by periodic clinical observations. Histological examinations were performed 24 hours after administration, and aqueous protein concentrations and cell counts were also determined. RESULTS Intraocular inflammation appeared within 6-9 hours of LTA intravitreal injection. became maximal at about 24-48 hours postinjection, and lasted for nearly 6 days. Intraocular inflammation was also induced by intravenous injection of LTA at a higher dose. Inflammation reached a peak 4-5 hours after injection, and rapidly disappeared in 24 hours. No cellular response was observed in intravenous LTA-treated eyes. CONCLUSIONS This study demonstrates that LTAs from gram-positive bacteria have the biological activity to induce intraocular inflammation in rabbits by intravitreal or intravenous injection. Therefore, we suggest that LTA may play a role in the pathogenesis of uveitis as one of the etiological factors.