Kenichi Namba

Genome-wide association studies identify IL23R - IL12RB2 and IL10 as Behçet's disease susceptibility loci

Behçets disease is a chronic systemic inflammatory disorder characterized by four major manifestations: recurrent ocular symptoms, oral and genital ulcers and skin lesions. We conducted a genome-wide association study in a Japanese cohort including 612 individuals with Behçets disease and 740 unaffected individuals (controls). We identified two suggestive associations on chromosomes 1p31.3 (IL23R-IL12RB2, rs12119179, P = 2.7 × 10−8) and 1q32.1 (IL10, rs1554286, P = 8.0 × 10−8). A meta-analysis of these two loci with results from additional Turkish and Korean cohorts showed genome-wide significant associations (rs1495965 in IL23R-IL12RB2, P = 1.9 × 10−11, odds ratio = 1.35; rs1800871 in IL10, P = 1.0 × 10−14, odds ratio = 1.45).

A Randomized, Placebo-Controlled Clinical Trial of Tacrolimus Ophthalmic Suspension 0.1% in Severe Allergic Conjunctivitis

AIMSnTo examine the efficacy of tacrolimus ophthalmic suspension 0.1% in treating severe allergic conjunctivitis.nnnMETHODSnThis was a multicenter, randomized, double-masked, placebo-controlled clinical trial. Fifty-six patients with severe allergic conjunctivitis in whom topical antiallergic agents and corticosteroids had been ineffective were randomized to tacrolimus or placebo treatment. Patients were treated either with tacrolimus or placebo twice-daily for 4 weeks. Severity of objective signs in palpebral and bulbar conjunctiva, limbus, and corneal involvement was assessed using 4 grades. Seven subjective symptoms were evaluated by visual analog scale (VAS) assessment. The primary efficacy endpoint was change in the total score of objective signs at the end of treatment. The secondary efficacy endpoints included change in the score for each objective sign and change in the VAS for each subjective symptom. Safety was assessed based on the severity and the incidence of adverse events.nnnRESULTSnMean change from baseline in total score for objective signs was significantly greater in the tacrolimus (-5.6 + or - 5.1) than in the placebo group (-0.1 + or - 4.5; P < 0.001). Tacrolimus significantly improved giant papillae (P = 0.001) and corneal involvement (P = 0.005). Five subjective symptoms (itching, discharge, hyperemia, lacrimation, and foreign body sensation) were significantly better in the tacrolimus than in the placebo group. The most frequent treatment-related adverse event in the tacrolimus group was mild ocular irritation upon topical instillation, which was well-tolerated.nnnCONCLUSIONnTacrolimus ophthalmic suspension 0.1% is effective in treating severe allergic conjunctivitis.

Genetic characterization and susceptibility for sarcoidosis in Japanese patients: risk factors of BTNL2 gene polymorphisms and HLA class II alleles.

PURPOSEnSarcoidosis is a heterogeneous and multisystem granulomatous disorder. The etiology still is uncertain, but the disease currently is thought to be triggered by various genetic as well as environmental factors. Recently, an association between sarcoidosis and the butyrophilin-like 2 (BTNL2) gene located in close proximity to the HLA-DRB1 gene was reported. The purpose of our study was to verify the relationship between BTNL2 and HLA risk alleles for the susceptibility to sarcoidosis, and to assess whether the BTNL2 association is independent of the HLA risk alleles.nnnMETHODSnIn our study, 11 single nucleotide polymorphisms (rs28362677, rs2076533, rs2076530, rs2076529, rs2294881, rs3763304, rs2076523, rs28362682, rs3806156, rs9268499, rs3763317), including the functional rs2076530 (G > A) of the BTNL2 gene, and HLA-DRB1 and -DQB1 alleles, were genotyped in 237 Japanese patients diagnosed with sarcoidosis and 287 healthy Japanese control subjects.nnnRESULTSnIn the patient group, the HLA-DRB1*08:03 (P = 6.15 × 10(-5), odds ratio [OR] = 2.43) and BTNL2 rs2076530_A (P = 6.90 × 10(-6), OR = 1.84) were associated with disease susceptibility. Upon stratification analysis in search for a synergistic effect given the extensive linkage disequilibrium between BTNL2 rs2076530_A and HLA-DRB1*08:03, our results suggested that the risk-bearing allele of these two loci interact negatively. No significant differences were observed in allele frequencies for alleles in patients with ocular and other systemic sarcoidosis.nnnCONCLUSIONSnOur studies implicated that the HLA-DRB1 allele is a major contributing genetic factor in the development of sarcoidosis in Japan. However, further studies are needed to verify how HLA or BTNL2 alleles confer the disease phenotype, severity of sarcoidosis.

Investigation of Association between TLR9 Gene Polymorphisms and VKH in Japanese Patients

Purpose: Vogt-Koyanagi-Harada (VKH) disease is an autoimmune disorder affecting melanocytes in the skin, eyes, inner ear, and meninges. The Epstein-Barr virus and cytomegalovirus (CMV) antigen have been hypothesized as possible triggering factors for the disease. Toll-like receptors (TLRs) play an important role in the induction of defense mechanisms of the innate and adaptive immune responses to microbial pathogens. Among TLRs, TLR9 recognizes unmethylated 2′-deoxyribo (cytidine-phosphate guanosine)(CpG) DNA motifs that are frequently present in viruses and plays a central role in the host defense against viral infection. The aim of this study was to investigate whether TLR9 polymorphisms were associated with VKH in a Japanese population. Methods: Ninety-four Japanese patients diagnosed with VKH and 125 healthy control subjects were recruited. Five single-nucleotide polymorphisms (SNPs: rs187084, rs5743836, rs352139, rs352140, rs5743845) in the TLR9 gene were genotyped, and allelic and phenotypic diversity was assessed between cases and control subjects. Results: Strong linkage disequilibrium was observed among three SNPs (D’ > 0.99), which were located in one haplotype block. Two SNPs (rs5743836 and rs5743845) were monopolymorphic in both cases and controls. No statistically significant association was observed for any of the SNPs between cases and controls. Conclusion: Three SNPs in the TLR9 gene were not significantly associated with susceptibility to VKH.

Prevention of experimental autoimmune uveoretinitis by blockade of osteopontin with small interfering RNA.

Osteopontin (OPN) is elevated during the progression of experimental autoimmune uveoretinitis (EAU) in C57BL/6 (B6) mice. Furthermore, EAU symptoms are ameliorated in OPN knockout mice or in B6 mice treated with anti-OPN antibody (M5). Recently, OPN has been shown to promote the Th1 response not only in the extracellular space as a secretory protein but also in cytosol as a signaling component. Thus, we attempted to reduce OPN in both compartments by using a small interfering RNA (siRNA) targeting the OPN coding sequence (OPN-siRNA). EAU was induced in B6 mice by immunization with human interphotoreceptor retinoid-binding protein (hIRBP) peptide sequence 1-20. The OPN- or control-siRNA was administered with hydrodynamic methods 24 h before and simultaneously with immunization (prevention regimen). When plasma OPN levels were quantified following siRNA administration with the prevention regimen, the level in the OPN-siRNA-treated group was significantly lower than that in the control-siRNA-treated group. Accordingly, the clinical and histopathological scores of EAU were significantly reduced in B6 mice when siRNA caused OPN blockade. Furthermore, TNF-alpha, IFN-gamma, IL-2, GM-CSF and IL-17 levels in the culture supernatants were markedly suppressed in the OPN-siRNA-treated group, whereas the proliferative responses of T lymphocytes from regional lymph nodes against immunogenic peptides was not significantly reduced. On the other hand, the protection was not significant if the mice received the OPN-siRNA treatment on day 7 and day 8 after immunization when the clinical symptoms appeared overt (reversal regimen). Our results suggest that OPN blockade with OPN-siRNA can be an alternative choice for the usage of anti-OPN antibody and controlling uveoretinitis in the preventive regimen.

Replication of a microsatellite genome-wide association study of Behçet's disease in a Korean population

OBJECTIVEnBehçets disease is one of the major aetiologies of uveitis causing blindness in Asian countries. A genome-wide association study identified six microsatellite markers as disease susceptibility loci for Japanese patients with Behçets disease. To confirm our recent results, these microsatellite markers were examined in a Korean population as a replication study.nnnMETHODSnStudy participants included 119 Behçets disease patients and 141 controls. All were enrolled in Korea. Association between the six reported microsatellite markers (D3S0186i, D6S0014i, D6S0032i, 536G12A, D12S0645i and D22S0104i) and Behçets disease was analysed. HLA-B was genotyped by sequence-based typing methods.nnnRESULTSnA microsatellite marker located near the HLA-B region demonstrated significant association with Behçets disease (Pu2009=u20090.028). The genotype and phenotype frequencies of the HLA-B*51 gene were significantly increased in patients (23.1 and 39.5%, respectively) compared with healthy controls (11.2 and 20.1%, respectively; Pu2009<u20090.001).nnnCONCLUSIONnMicrosatellite analysis revealed that the HLA-B*51 gene was strongly associated with Behçets disease in a Korean population.

Elevation of surfactant protein D, a pulmonary disease biomarker, in the sera of uveitis patients with sarcoidosis

PurposeSurfactant protein D (SP-D) is found in the epithelial cells of multiple mucosal surfaces. It is commonly used to diagnose and screen for pulmonary diseases. In the present study, serum levels of SP-D were measured in patients with uveitis to ascertain whether SP-D is a clinically useful laboratory parameter to diagnose sarcoidosis.MethodsSera were obtained from 81 patients with sarcoidosis, 16 patients with Behçet disease, 40 patients with HLA-B27 associated uveitis, 50 patients with Vogt-Koyanagi-Harada (VKH) disease, and 33 healthy volunteers. Serum SP-D levels were quantified with an SP-D enzyme immunoassay kit.ResultsIn the healthy control subjects, the average serum SP-D level was 39.70 ng/ml; in the uveitis patients with sarcoidosis, the mean serum SP-D level was 57.0 ng/ml, and in the uveitis patients with other etiologies the mean levels were 38.63 ng/ml for Behçet disease, 38.18 ng/ml for HLA-B27 associated uveitis, and 31.32 ng/ml for the VKH patients. The average serum SP-D levels of patients with sarcoidosis were significantly higher than those of patients with any other uveitis etiologies or healthy controls (P < 0.01).ConclusionsSP-D may be a less invasive and less expensive laboratory examination for sarcoidosis screening. SP-D should be considered as a new laboratory parameter for the diagnosis of uveitis and sarcoidosis.