Role of IL-22- and TNF-α-producing Th22 cells in uveitis patients with Behcet's disease.

Behçet's disease is a systemic inflammatory disorder with recurrent episodes of oral ulceration, skin lesions, genital ulceration, and intraocular inflammation (uveitis). The intraocular inflammation is strictly associated with Th effector cells. IL-22 is a member of the IL-10 cytokine family that is involved in inflammatory processes. Recently, Th22 cells were identified as a Th cell population that produces IL-22 and TNF-α and are distinct from Th1, Th2, and Th17 cells. In this study, we established Th22-type T cell clones from ocular samples taken from Behçet's disease patients with active uveitis. These clones produced large amounts of IL-22 and TNF-α but not the Th1 cytokine IFN-γ and the Th17 cytokine IL-17. CD4(+) T cells from the peripheral blood of Behçet's disease patients differentiated into Th22 cells in the presence of IL-6 and TNF-α in vitro. The polarized Th22 cell lines produced large amounts of IL-22, and the polarized Th1 and Th17 cells also produced IL-22. In the presence of anti-TNF-α- and anti-IL-6-blocking Abs, Behçet's disease Th22-type T cells failed to produce IL-22. In addition, infliximab-pretreated Th22 cells and Th22-type ocular T cells produced less IL-22 and TNF-α. Moreover, IL-22-producing T cells were isolated from mice with experimental autoimmune uveitis, an animal model of Behçet's disease, and the intraocular T cells from uveitis models produced large amounts of IL-22 in the presence of retinal Ags. Our results suggest that inflammatory cytokines IL-22 and TNF-α may play a key role in the ocular immune response in Behçet's disease.

Retinoic acid from retinal pigment epithelium induces T regulatory cells.

Primary cultured retinal pigment epithelial (RPE) cells can convert T cells into T regulatory cells (Tregs) through inhibitory factor(s) including transforming growth factor ß (TGFß) in vitro. Retinoic acid (RA) enhances induction of CD4(+) Tregs in the presence of TGFß. We investigated whether RA produced by RPE cells can promote generation of Tregs. We found that in vitro, RA-treated T cells expressed high levels of Foxp3 in the presence of recombinant TGFß. In GeneChip analysis, cultured RPE cells constitutively expressed RA-associated molecules such as RA-binding proteins, enzymes, and receptors. RPE from normal mice, but not vitamin A-deficient mice, contained significant levels of TGFß. RPE-induced Tregs from vitamin A-deficient mice failed to suppress activation of target T cells. Only a few Foxp3(+) T cells were found in intraocular cells from vitamin A-deficient experimental autoimmune uveitis (EAU) mice, whereas expression was higher in cells from normal EAU mice. RA receptor antagonist-pretreated or RA-binding protein-siRNA-transfected RPE cells failed to convert CD4(+) T cells into Tregs. Our data support the hypothesis that RPE cells produce RA, thereby enabling bystander T cells to be converted into Tregs through TGFß promotion, which can then participate in the establishment of immune tolerance in the eye.

Optical coherence tomography for retinal detachment with a macular hole in a highly myopic eye.

Optical coherence tomography can facilitate observation of the macula in highly myopic eyes, which may be difficult using an ophthalmoscope because of myopic chorioretinal atrophy. The use of optical coherence tomography to record the process of retinal reattachment and closure of a macular hole in a highly myopic eye following macular buckling surgery is described.

Clinical course of patients with Behçet's uveitis following discontinuation of infliximab therapy.

PURPOSE: To investigate the clinical course of Behçet's uveitis patients following discontinuation of infliximab therapy. METHODS: This retrospective chart review study examined Behçet's disease patients who received infliximab treatment between 2000 and 2012. Medical records of patients whose infliximab treatment was discontinued were reviewed, with special focus on the frequency of uveitis attacks in the period before initiation, during treatment and after cessation of the infliximab therapy. Mean visual acuities were evaluated for each treatment period. RESULTS: Out of the 43 patients treated with infliximab at our uveitis clinic, ten were discontinued due to adverse events or inefficiency. Data for seven patients followed for more than 12 months before initiation and after cessation of infliximab were analyzed. Frequency of acute uveitis attacks was 7.43 per 12 months before initiation of infliximab, 2.86 during treatment and 0.57 after cessation. A statistically higher frequency of uveitis attacks was observed before initiation of infliximab compared to during (p < 0.05) and after cessation of treatment (p < 0.05). There was no statistical significance observed between the period during treatment and after cessation (p = 0.29). The mean logMAR was 0.79 at baseline, 0.68 during treatment, and 0.88 at 12 months after cessation. These differences were not statistically significant. CONCLUSIONS: A satisfactory clinical course with well-controlled ocular inflammation was found after discontinuation of infliximab therapy in Behçet's uveitis patients. These results suggest that a safe, pre-planned discontinuation of infliximab therapy can be performed in patients with Behçet's uveitis.

Suppression of IL-22-producing T helper 22 cells by RPE cells via PD-L1/PD-1 interactions.

PURPOSE: To determine whether RPE cells can suppress a novel T helper subset, the Th22 cells, via costimulatory interactions. METHODS: Primary RPE cells were established from normal C57BL/6 mice. The target CD4(+) Th22 cells from spleen cells in wild-type control or knockout donors were used. T cell activation was assessed by examining BrdU incorporation (proliferation) and cytokine production. Expression of costimulatory molecules on RPE cells and expression of costimulatory receptors on target Th22 cells were evaluated by flow cytometry. Neutralizing antibodies were used to abolish the suppression function. In addition, human RPE cells and target Th22 cells induced from human CD4(+) cells were also used in similar experiments. RESULTS: Cultured RPE cells significantly suppressed activation of target Th22 cells (e.g., T cell proliferation and IL-22 production). Moreover, human RPE cells suppressed Th22 cell lines and T cell clones established from active uveitis patients. Although cultured RPE cells expressed various costimulatory molecules including programmed cell death 1 ligand 1 (PD-L1), only PD-L1 on the RPE cells was actually delivered to the target Th22 cells. Th22 cells greatly express programmed cell death 1 (PD-1), and RPE cells failed to suppress IL-22 expression by target Th22 cells from PD-1 knockout donors. In addition, if neutralizing antibodies for PD-L1 were cocultured with RPE cells, Th22 suppression was impaired. CONCLUSIONS: RPE cells express PD-L1 costimulatory molecules and suppress bystander Th22-type PD-1(+) bystander T cells through negative costimulatory interactions.

Psoriasis triggered by infliximab in a patient with Behçet's disease.

PURPOSE: To report a case of psoriasis triggered by anti-tumor necrosis factor-alpha (TNF-α) therapy in a uveitis patient with Behçet's disease. CASE REPORT: A 34-year-old man with established Behçet's disease was started on infliximab therapy for recurrent uveitis and showed an excellent response. After 2 years of infliximab treatment, he developed erythematous scaly plaques on both of his palms and heels. No clinical or serological evidence of infection was found, and there was no personal/family history of psoriasis. Histological examination of one lesion showed that it was consistent with psoriasis. Because of the development of hyperkeratotic skin lesions consistent with guttate psoriasis, the infliximab treatment was discontinued. Six months later, the psoriasis had resolved. CONCLUSIONS: Blockade of TNF-α is an effective treatment for psoriasis as well as Behçet's disease. However, we have to consider new-onset psoriasis as an adverse side effect that can be triggered by anti-TNF-α therapy in Behçet's disease.

Mature dendritic cell suppression by IL-1 receptor antagonist on retinal pigment epithelium cells.

PURPOSE: To determine whether retinal pigment epithelial (RPE) cells can inhibit mature dendritic cells (mDCs). METHODS: Cultured RPE cells were established from C57BL/6 mice. DCs were established from bone marrow cells of normal mice, and mDCc were induced by culture in medium containing granulocyte macrophage-colony-stimulating factor (GM-CSF) and IL-4 in the presence of lipopolysaccharide and TNF-α. Activation of mDCs was assessed by a proliferation assay and ELISA to measure the production of pro-inflammatory cytokines (TNF-α, IL-1ß, and IL-12p40). Expression of major histocompatibility complex (MHC) class II, CD11c, and costimulatory molecules such as CD80, CD86, programmed cell death 1 ligand 1 (PD-L1), and PD-L2 on mDCs or RPE-exposed mDCs was evaluated by immune staining and flow cytometry. Production of IL-1 receptor antagonist (IL-1Ra) by RPE cells was evaluated by oligonucleotide microarray or ELISA. Anti-IL-1Ra neutralizing antibodies or RPE cells from IL-1Ra knockout donors were used for the assay. RESULTS: Cultured RPE cells greatly suppressed the activation of mDCs, especially the production of pro-inflammatory cytokines, and the expression of cell-surface molecules. Moreover, RPE cells significantly suppressed mixed lymphocyte reactions by mDCs. In an examination of immunoregulatory candidate molecules, RPE cells expressed much higher levels of IL-1Ra as compared with control cells, and RPE cells pretreated with recombinant TNF-α and/or IL-1ß produced high levels of IL-1Ra. RPE cells in the presence of anti-IL-1Ra antibodies, but not other candidate factors, failed to suppress activation by mDCs. In addition, RPE cells from IL-1Ra null donors failed to suppress mDC activation. CONCLUSIONS: Our results suggest that ocular resident cells can produce pro-inflammatory cytokine antagonist that suppresses antigen-presenting cell activation.

Inhibition of Th17 differentiation by anti-TNF-alpha therapy in uveitis patients with Behçet's disease.

INTRODUCTION: The purpose of this study was to determine whether anti-tumour necrosis factor alpha (anti-TNF-α) antibody, infliximab, can inhibit T helper 17 (Th17) differentiation in uveitis patients who have Behçet's disease (BD). METHODS: To measure inflammatory cytokines, ocular fluid samples from BD patients being treated with infliximab were collected. Cluster of differentiation 4 (CD4)+ T cells from BD patients with active uveitis were co-cultured with anti-cluster of differentiation 3/cluster of differentiation 28 (CD3/CD28) antibodies in the presence of infliximab. For the induction of Th17 cells, CD4+ T cells from BD patients were co-cultured with anti-CD3/CD28, anti-interferon-gamma (anti-IFN-γ), anti-interleukin-4 (anti-IL-4), and recombinant proteins such as interleukin-1 beta (IL-1ß), interleukin-6 (IL-6), interleukin-23 (IL-23), and TNF-α. The BD T cells were co-cultured with infliximab, and the production of interleukin-17 (IL-17) was evaluated by ELISA and flow cytometry, and the expression of retinoid-acid receptor-related orphan receptor gamma t (RORγt) was also evaluated by flow cytometry. In addition, intraocular cells collected from mice with experimental autoimmune uveitis (EAU) were used for the assay with anti-TNF-α blocking antibody. RESULTS: Ocular fluids from active uveitis patients who have BD contained significant amounts of inflammatory cytokines such as IFN-γ, IL-2, TNF-α, IL-6, and IL-17, while ocular fluids from infliximab patients did not contain any inflammatory cytokines. Activated CD4+ T cells from BD patients produced large amounts of TNF-α and IL-17, whereas T cells in the presence of infliximab failed to produce these cytokines. Polarized Th17 cell lines from BD patients produced large amounts of IL-17, and Th17 cells exposed to infliximab had significantly reduced IL-17 production. Polarized BD Th17 cells expressed large amounts of transcription factor RORγt. In contrast, in vitro-treated infliximab Th17 cells expressed less RORγt. Moreover, intraocular T cells from EAU mice had a high population of IL-17+ cells, and retinal antigen-specific T cells from EAU mice produced large amounts of IL-17 in the presence of retinal peptide. However, the EAU T cells produced less IL-17 if the T cells were treated with anti-TNF-α antibody. CONCLUSIONS: These results indicate that anti-TNF-α therapy suppresses effector T-cell differentiation in BD patients with uveitis. Thus, suppression of effector T-cell differentiation by anti-TNF-α therapy may provide protection from severe ocular inflammation in BD.

Inhibitory effect of corneal endothelial cells on IL-17-producing Th17 cells.

AIM: To determine whether cultured corneal endothelial (CE) cells suppress interleukin 17 (IL-17)-producing effector T cells in vitro. METHODS: CE cell lines established from a normal mouse were used. Target bystander T cells were established from normal splenic T cells with anti-CD3 antibodies. Production of IL-17 by target T cells was evaluated by ELISA, flow cytometry and quantitative PCR. To abolish the CE-inhibitory function, transforming growth factor ß (TGFß)-small interfering RNA-transfected CE cells or transwell membrane inserts, which block cell-to-cell contact, were used. RESULTS: Cultured CE cells greatly suppressed the activation of bystander target cells (pan-T, CD4 T, CD8 T, and B cells) in vitro, particularly inflammatory cytokine production by CD4 cells. Cultured CE cells significantly suppressed IL-17-producing T cells and fully suppressed polarised T helper 17 (Th17) cell lines that are induced by Th17-associated differentiation factors. However, CE cells failed to suppress Th17 cells if the CE cell lines were pretreated with TGFß small interfering RNA or if direct contact with T cells was blocked with transwell membrane inserts. CONCLUSION: CE cells impair the effector functions and activation of IL-17-producing helper T cells in a cell-contact-dependent mechanism. Thus, corneal endothelium may contribute to the maintenance of the privileged immune status in the eye by inducing peripheral immune tolerance.

Immunosuppressive properties of regulatory T cells generated by incubation of peripheral blood mononuclear cells with supernatants of human RPE cells.

PURPOSE: To determine whether supernatants of human retinal pigment epithelium (RPE) cells can convert CD4⁺ T cells into regulatory T cells (Tregs) under Treg-induction conditions in vitro and in vivo. METHODS: Peripheral blood mononuclear cells were cocultured with supernatants from TGFß2-pretreated human RPE lines on anti-CD3-coated plates. Cells were then separated with a CD4⁺CD25⁺ Treg isolation kit and cultured with supernatants from RPE, anti-CD3/CD28 antibodies, high-dose IL-2, and TGFß2. By flow cytometry sorting, CD25⁺CD45RA⁻ Tregs were separated. Expressions of CD25(high), Foxp3, CD152, and TNFRSF 18 on Tregs were analyzed by flow cytometry. Cytokine production by Tregs was measured by ELISA. Proliferation of target T cells was assessed by [³H]thymidine incorporation or CFSE incorporation. In addition, mouse RPE-induced Tregs were used for the in vitro assay and in vivo experimental autoimmune uveitis (EAU) models. RESULTS: Human RPE-induced Tregs expressed higher levels of the Treg markers CD25(high), Foxp3, CD152, and TNFRSF 18. In addition, RPE-induced Tregs included significant numbers of CD4⁺CD25(high)Foxp3(high)CD45RA⁻ active effector Tregs that significantly suppressed the activation of Th1/Th17 cell lines, indicating that they have immunosuppressive properties. Furthermore, CD4⁺CD25(low)Foxp3(low)CD45RA⁻ nonsuppressing cytokine-secreting T cells were removed from the in vitro-manipulated Treg population. Administration of mouse RPE-induced Tregs significantly suppressed ocular inflammation in mice with EAU. In addition, the Tregs suppressed retinal antigen-specific T cells in vitro. CONCLUSIONS: It is hoped that through the data provided in this study that Tregs might become useful as individualized therapeutic agents for ocular autoimmune diseases.

Suppression of interleukin-17-producing T-helper 17 cells by retinal pigment epithelial cells.

PURPOSE: To determine whether retinal pigment epithelial (RPE) cells can inhibit cytokine production by activated T helper (Th) cells. METHODS: Primary RPE cells were cultured from normal C57BL/6 mice. Target bystander T cells were established from normal splenic T cells with anti-CD3 antibodies. T-cell activation was assessed for production of cytokines, determined by ELISA. Production of IL-17 on target T cells was evaluated using oligonucleotide microarray, RT-PCR and flow cytometry. TGFß small interfering RNA was used to inhibit the RPE cells' inhibitory function. RESULTS: The cultured RPE cells greatly suppressed the activation of bystander CD4(+) T cells in vitro, especially cytokine production by target T helper cells (Th1 cells, Th2 cells and Th17 cells, but not Th3 cells). The cultured RPE cells and RPE supernatants significantly suppressed the IL-17-producing CD4(+) T cells and fully suppressed the polarized Th17 cell lines that were induced by recombinant proteins IL-6 and TGFß2. However, the RPE cells failed to suppress the IL-17-producing T cells in the presence of rIL-6. In addition, the TGFß produced by the RPE cells suppressed the Th17 cells. CONCLUSIONS: These results indicate that RPE cells have an immunosuppressive effect on Th17-type effector T cells, which highlights a role for ocular resident cells in establishing immune regulation in the eye.