Yoh-Ichi Kawano

Immunoregulatory Role of Ocular Macrophages: The Macrophages Produce RANTES to Suppress Experimental Autoimmune Uveitis

Murine experimental autoimmune uveitis (EAU) is a model of human uveitis. Ocular-infiltrating macrophages play a crucial role in the generation of tissue damage in EAU. In fact, several chemokines are actually produced in the inflamed eye. The aim of this study was to elucidate the role of ocular macrophage-derived chemokines in EAU. C57BL/6 mice were immunized with human interphotoreceptor retinoid binding protein peptide 1–20, and the EAU severity was scored at multiple time points based on microscopic fundus observations (retinal vascular dilatation and exudates) and histological examinations. The peak inflammatory response was observed 1 wk (day 16) after the beginning of macrophage infiltration to the eye (day 9). Ocular-infiltrating cells were enriched or depleted of macrophages by magnetic beads and analyzed by real-time RT-PCR for chemokine mRNA production. We found that only the macrophage-enriched cells from the eye produced RANTES, and thus proposed that macrophage-derived RANTES facilitated the ocular inflammations. In contrast to our postulate, neutralization of RANTES by specific Ab in vivo on days 9 and 13 exacerbated EAU. We also found that the ratio of ocular CD4/CD8 T cells was markedly increased after treatment. As a result, RANTES neutralization might exacerbate EAU by modulating the type of T cell subsets recruited to the eye. In conclusion, our data provide insight into the immunoregulatory role of macrophages and RANTES in the pathogenesis of ocular inflammation. Not all macrophage-derived chemokines cause local inflammation, since RANTES produced by ocular macrophages appears to suppress EAU.

Ultrasound Biomicroscopic Analysis of Transient Shallow Anterior Chamber in Vogt-Koyanagi-Harada Syndrome

PURPOSE To evaluate the mechanism of formation of the transient shallow anterior chamber in Vogt-Koyanagi-Harada syndrome. METHODS Two patients with Vogt-Koyanagi-Harada syndrome with shallow anterior chambers were examined with an ultrasound biomicroscope. RESULTS A ciliochoroidal detachment, which was not obvious on ophthalmoscopic examination, was clearly demonstrated in both patients by ultra-sound biomicroscopy. The detachment disappeared after systemic corticosteroid therapy. CONCLUSION The shallowing of the anterior chamber in two patients with Vogt-Koyanagi-Harada syndrome was caused by suprachoroidal effusion secondary to inflammation of the uvea.

Increased number of IgE positive Langerhans cells in the conjunctiva of patients with atopic dermatitis

AIM To determine the role of Langerhans cells (LCs) found to bear IgE in patients with atopic dermatitis (AD) by evaluating the surface distribution of these cells in the conjunctival epithelium and epidermis of skin lesions in patients with AD. METHODS The double labelling method was used to evaluate IgE positive cells that were positive for anti-CD1a or anti-CD23 antibody in an epithelial sheet of the conjunctival limbus. Specimens of conjunctiva were obtained from 12 men, six of whom had AD and ocular complications. Five patients without atopic disease served as controls, plus one additional patient with asthma but no AD. A similar study was conducted using epidermal sheets obtained from two patients with AD and from one without AD. RESULTS The number of CD1a+ cells present in the conjunctival epithelium of the patients with AD significantly exceeded that of the patients without AD. Most CD1a+ cells in the conjunctival epithelium and epidermis from the patients with AD bore IgE on their surfaces. Few such cells from patients without AD bore IgE. No CD23+ cells were found in the patients with or without AD. CONCLUSIONS The presence of an increased number of LCs bearing IgE on their surfaces in the conjunctival epithelium of patients with AD suggests that these cells may be involved in eliciting the hypersensitivity reaction and participate in ocular inflammation.

Detection of Varicella-Zoster Virus Genome Having a Pstl Site in the Ocular Sample from a Patient with Acute Retinal Necrosis

We detected the virus genome in ocular samples from a 65-year-old woman with clinically diagnosed acute retinal necrosis using DNA amplification. She exhibited occlusive retinal vasculitis, confluent necrotizing retinitis, mainly peripheral, and iridocyclitis. For DNA amplification, we used recently published primers specific for varicella-zoster virus (VZV) and herpes simplex virus. Using VZV primers, we detected the VZV genome in the aqueous humor, but not in the vitreous, by amplifying a DNA fragment 642 base pairs in length. HSV DNA was not detected. After detecting the VZV genome, PstI restriction endonuclease was used because an epidemiological study found that about 25% of the VZV strains in Japan carry a mutation lacking a PstI recognition site. The VZV genome from the patient had a PstI cleavage pattern, while the positive control had a VZV genome that carried a PstI-site-less mutation. We considered our patient with acute retinal necrosis to be infected with VZV having a PstI site.

Apoptosis in perforated cornea of a patient with graft-versus-host disease

CASE REPORT Although ocular complications associated with graft-versus-host disease (GVHD) can include corneal dysfunction, corneal perforation is not common. We report the presence of apoptotic cells in a perforated cornea of a patient with GVHD. A 72-year-old man with the angioimmunoblastic type of malignant lymphoma developed chronic GVHD after allogeneic peripheral blood stem cell transplantation. Despite systemic and topical treatment, both corneas perforated, and penetrating keratoplasty with cataract extraction and intraocular lens implantation was performed on both eyes. COMMENTS The corneal button excised from the right eye was examined histologically and stained for apoptotic cells by TdT-mediated dUTP nick end labeling (TUNEL). This revealed thinning of the epithelial cell layer and stroma, with cells, including lymphocytes, infiltrating to the site of the perforation. Some of the epithelial cells and keratocytes were TUNEL positive. The presence of apoptotic cells in our case suggests that apoptosis may be involved in the perforation of the cornea in patients with GVHD.

Inverse relationship in H-2-associated lysis between NK cells and rIL-2-activated killer cells: Evidence from in vitro killing and metastatic experiments

We investigated the manner in which rIL-2 induced effectors in vitro (LAK cells), which, like NK cells, lyse targets nonspecifically and discriminate nonself, and how H-2 as the self-marker affects the LAK cell killing mechanism. NK cells showed an appreciably higher killing activity to B16 melanoma H-2- cells than to H-2+ cells. In contrast, LAK cells lysed more efficiently to H-2+ cells. The in vivo experiments showed that the NK cells prevented pulmonary metastasis of B16 H-2- cells in the normal syngeneic host, whereas the transferred LAK cells had a preferential inhibitory effect on the pulmonary metastasis of B16 H-2+ cells in the immunodeficient syngeneic hosts. Taken together, these results show that the H-2-encoded or H-2-associated molecules contribute to the triggering signal in the lysis by LAK cells, whereas the NK cells recognize the reduced self H-2 expression on the targets, thereby contributing to a trigger of the lysis.

Does depression of NK activity cause lymphadenopathy in lpr mice

B6-lpr/lpr mice develop massive T cell lymphoproliferation, as associated with autoimmune disease. We found a reduced NK activity in the spleen of B6-lpr/lpr mice. Neonatal thymectomy markedly retarded the development of lymphoproliferation and the development of autoantibodies in the B6-lpr/lpr mice. These animals had a higher level of NK activity in the spleen. When the neonatally thymectomized B6-lpr/lpr mice were given anti-asialo GM1 serum (30 microliter) four times at 6-day intervals, initiated at the 8th-10th postnatal week, these mice developed lymphoproliferative disorders and splenomegaly, concomitantly with depression of NK activity. It is therefore tempting to speculate that NK cells are involved in the regulation of the occurrence of lymphoproliferative disorders.

CXCR2 Expression on Neutrophils is Upregulated During the Relapsing Phase of Ocular Behçet Disease

Purpose: To search for markers of Behçet disease (BD) activity, we measured CXCR1 and CXCR2 levels on the circulating leukocytes of patients suffering from ocular BD. Methods: Peripheral blood leukocytes were harvested from healthy volunteers (n = 16) and ocular BD patients (n = 35). The patients consisted of 15 individuals in relapsing phase (6 with prednisolone treatment) and 20 individuals in remission phase (9 with prednisolone treatment). Expression of CXC chemokine receptors (CXCRs) on leukocytes (including lymphocytes, monocytes, neutrophils) was measured using flow cytometry. Results: Without prednisolone treatment, CXCR2 expression (on both total leukocytes and neutrophils) in relapsing phase was significantly higher than in remission-phase patients or normal individuals. By contrast, no significant difference was detected in the expression of CXCR1 between any of the groups. Importantly, low-dose prednisolone therapy reduced CXCR2 expression on neutrophils. Conclusions: CXCR2 has a potential role in promoting uveitis during ocular attack and might also be a useful marker for disease activity.

Adoptive transfer of H-2-incompatible lymphokine-activated killer (LAK) cells: an approach for successful cancer immunotherapy free from graft-versus-host disease (GVHD) using murine models

We investigated whether the adoptive transfer of H-2-incompatible lymphokine-activated killer (LAK) cells would efficiently demonstrate antitumor activity without damaging the normal host cells. Allogeneic LAK cells (5 X 10(7] did not cause graft-versus-host disease (GVHD) in irradiated recipients, whereas more than half of the mice transferred with the same dose of fresh allogeneic spleen cells developed GVHD. Repeated transfer (three times at 4-day intervals, 1.2 X 10(8) cells/mouse) did not result in GVHD. Graft-versus-host reaction (GVHR), which is detectable by spleen enlargement of recipients transferred with allogeneic lymphoid cells was also absent in LAK cell-transferred mice of all strain combinations tested. Host immune responses were not affected in these mice. Therefore, it is feasible to transfer allogeneic LAK cells. With the antitumor efficacy of allogeneic LAK cells, they preferentially lysed allogeneic tumor targets. Adoptive transfer of the allogeneic LAK cells led to a significant decrease in the lung-colonizing foci of intravenously inoculated B16 melanoma cells. Allogeneic LAK cells and syngeneic ones were equally active, in vivo. The use of allogeneic LAK cells may prove to be a valuable method for effective clinical antitumor immunotherapy.

Host H-2 genotype regulates the metastatic ability of H-2-associated variants of B16 melanoma: defense systems screening for absence of self H-2 components by natural killer cells and host-associated homing barrier.

The mechanisms of host H-2-associated resistance against metastasis of tumor cells were evaluated in relation to the H-2 phenotype of tumor cells. We used H-2 heterozygous H-2a/b and H-2d/b, and H-2 homozygous H-2b/b hosts, and H-2-associated variant lines of B16 cells (H-2b+, H-2b-). In H-2b/b hosts, H-2+ cells were highly metastatic in vivo, and were resistant to host NK effectors in vitro. Therefore, H-2a/b and H-2d/b hosts showed resistance to metastasis of H-2+ cells and their effectors showed killing activity to these cells in vitro. Though the host resistance was reduced by anti-asialo GM1 serum treatment, these hosts continued to demonstrate a considerable resistance against early survival and metastasis of the B16 cells. To evaluate this natural resistance, aside from the NK system, radiation bone marrow chimeras of F1-parental combinations were used. The data suggest that host MHC-associated resistance involves not only the NK defense system but also the host environmental resistance. Both exert resistance by recognizing the H-2 mismatch in relation to the host.