Indoleamine 2,3-dioxygenase 1 in corneal endothelial cells limits herpes simplex virus type 1-induced acquired immune response.

BACKGROUND: Corneal endothelial cells are known to be targets of herpes simplex virus type 1 (HSV-1) infection; however, the pathogenesis of HSV infections of the endothelial cells has not been definitively determined. The purpose of this study was to examine an unrecognised strategy of corneal endothelial cells to protect themselves from HSV-1 infection. METHODS: Immortalised human corneal endothelial cells (HCEn) were infected with HSV-1. Based on the global transcriptional profile, the expression of indoleamine 2,3-dioxygenase 1 (IDO1) was determined using real-time PCR and western blots. To examine whether IDO1 has any antiviral role, we tested whether viral replication was affected by blocking the activity of IDO1. The immune modulatory role of IDO1 was analysed to determine whether IDO1 might contribute to modulating the recall responses of HSV-1-sensitised CD4(+) T cells. RESULTS: IDO1 was strongly expressed in HCEn cells after HSV-1 infection. IDO1 blockade did not significantly restrict viral transcription or replication, arguing against a previously recognised antiviral role for IDO1. When HCEn cells were examined for antigen-presenting function, HSV-1-primed HCEn cells stimulated the proliferation of allogeneic CD4(+) T cells and interleukin 10 (IL-10) secretion. When the recall response to HSV-1 was measured by the mixed lymphocyte reaction, the HCEn-stimulated CD4(+) T cells modulated and limited the recall response. When IDO1 was silenced in HCEn cells, the HCEn-mediated immune modulatory activity and regulatory T-cell activation were reduced. Overexpression of IDO1 promoted immune modulatory activity, which was partly conveyed by IL-10. CONCLUSIONS: IDO1 induced by HSV-1 infection limits and dampens excessive acquired immune responses in corneal endothelial cells.

Clinical features and management of cytomegalovirus corneal endotheliitis: analysis of 106 cases from the Japan corneal endotheliitis study.

AIMS: The purpose of this study is to elucidate the clinical manifestations and the current treatment status of cytomegalovirus (CMV) endotheliitis via a large case series obtained from a national survey conducted in Japan. METHODS: The Japan Corneal Endotheliitis Study Group proposed diagnostic criteria for CMV endotheliitis based on a viral examination by PCR of aqueous humour, in combination with clinical manifestations. A national survey was then retrospectively conducted among 1160 members of the Japan Cornea Society. The study reviewed the patient profiles, clinical manifestations, and treatment modalities of individuals who met the diagnostic criteria for CMV endotheliitis. RESULTS: The study included 109 eyes of 106 patients. Mean patient age was 66.9±10.9 years (85 males (80.2%), 21 females (19.8%)). Patients were commonly diagnosed with anterior uveitis and ocular hypertension prior to confirmation of CMV endotheliitis. Coin-shaped lesions were observed in 70.6%, and linear keratic precipitates in 8.3% of the patients, respectively. 95% of cases were treated with anti-CMV drugs. CONCLUSIONS: CMV endotheliitis is most common in middle-aged and elderly men. CMV endotheliitis should be suspected when patients present with corneal endotheliitis involving coin-shaped lesions accompanied by anterior uveitis and ocular hypertension.

Relationship between the number of cytomegalovirus in anterior chamber and severity of anterior segment inflammation.

PURPOSE: To characterize the cytomegalovirus-associated anterior segment inflammation and to determine whether the number of cytomegalovirus is significantly correlated with the disease characteristics. METHODS: Retrospective consecutive case series. Seventy-three patients with refractory anterior segment inflammation due to iridocyclitis, corneal endotheliitis and keratouveitis were studied. All the patients were suspected to have cytomegalovirus infection and had undergone real-time PCR of the aqueous humor to determine the amount of cytomegalovirus DNA. RESULTS: Cytomegalovirus DNA was detected in 24 of the 73 cases. The cytomegalovirus copy number was significantly correlated with the number of recurrent episodes and glaucoma treatment levels, but was not significantly correlated with the disease type. A high cytomegalovirus copy number was a significant risk factor for IOP elevation [Odds ratio (OR) per logarithm CMV amount: 2.5 (95 % confidence interval (CI) 1.1-5.4), presence of coin-shaped lesions (2.3 (1.3-4.0)), recurrent inflammation (2.1 (1.3-3.5)), and reduction of endothelial cell densities (1.7 (1.2-2.5))]. An IOP elevation [OR 18.2 (95 % CI 2.2-153.0)], reduction of endothelial cell densities [13.2 (2.9-60.0)], and recurrent inflammations [11.9 (2.5-56.6)], but not the disease type, were significant predictors of the presence of >10(3) copies/ml cytomegalovirus in the aqueous. CONCLUSIONS: Measurements of the cytomegalovirus DNA amount is useful for evaluating the severity of the anterior segment inflammation.

Efficacy of herpes virus helicase-primase inhibitor, ASP2151, for treating herpes simplex keratitis in mouse model.

AIMS: To determine the efficacy of a new helicase-primase inhibitor, ASP2151, for treating herpetic keratitis. METHODS: Murine corneas were infected with herpes simplex virus type 1 (HSV-1). ASP2151 was administered orally or topically, and the severity of epithelial dendritic keratitis was determined. The effectiveness of ASP2151 was compared with that of acyclovir and valacyclovir. The reduction of the amount of HSV in tears, enucleated eyes and trigeminal ganglia was determined by real-time PCR or plaque assay. RESULTS: Orally administered ASP2151 reduced the epithelial keratitis score significantly more than that of the vehicle-treated group (p<0.01). It also lowered the HSV-DNA levels in the tears significantly more than that by valacyclovir (p<0.01). ASP2151 ointment resulted in the same reduction of the keratitis score as acyclovir ointment, and lowered the HSV DNA in tears more than acyclovir ointment. Topical instillation of ASP2151 improved the herpetic dendritic keratitis score significantly and reduced the titre of HSV DNA in the tears in a dose-responsive way. CONCLUSIONS: ASP2151 had significantly better anti-HSV activity against herpes simplex keratitis than valacyclovir and acyclovir after systemic or topical use. These findings indicate that ASP2151 should be considered as an alternative treatment for herpes simplex keratitis.

Four cases of Acanthamoeba keratitis treated with phototherapeutic keratectomy.

PURPOSE: To report 4 cases of Acanthamoeba keratitis treated with excimer laser phototherapeutic keratectomy (PTK) and to discuss the clinical efficacy of this procedure. METHODS: Four cases with early stage Acanthamoeba keratitis resistant to medical amoebic therapy for at least 1 week and with an enlarged abscess underwent PTK. RESULTS: After PTK, the infected corneal lesions were removed and the clinical symptoms rapidly resolved in all cases. Another 40-µm ablation was required as a result of the 1-week delay in performing PTK. There was no recurrence during the postoperative period. CONCLUSION: When lesions are limited to about one third of the superficial corneal stromal layer, PTK could be the most beneficial option for treating Acanthamoeba keratitis, resistant to medical amoebic therapy using chlorhexidine or polyhexamethylene biguanide, because of direct removal of resistant amoebic cysts and better visual recovery without irregular astigmatism.

Two cases of acanthamoeba keratitis diagnosed only by real-time polymerase chain reaction.

PURPOSE: To report 2 cases of Acanthamoeba keratitis whose causative pathogen was detected only by real-time polymerase chain reaction (PCR). METHODS: Histological examinations of corneal scrapings were stained with Fungiflora Y. Corneal scrapings were also cultured on nonnutrient agar. Real-time PCR analyses of corneal scrapings were also performed. RESULTS: Both cases had clinical signs and risk factors of Acanthamoeba infection. Histological examinations of corneal scrapings with Fungiflora Y staining were negative, and the cultures did not grow any pathogens. Real-time PCR analysis was positive for Acanthamoeba DNA from 2 corneal scrapings. Antiamoebic treatments led to excellent clinical improvements. CONCLUSIONS: These results indicate that PCR analyses can detect the DNA of Acanthamoeba in corneal scrapings and may be a valuable supplemental examination. This method is especially helpful when clinical signs and risk factors of Acanthamoeba infection are present but histological examinations with Fungiflora Y staining and cultures are negative.

Prevalence and features of keratitis with quantitative polymerase chain reaction positive for cytomegalovirus.

PURPOSE: To assess corneal scrapings and aqueous humor samples analyzed by polymerase chain reaction (PCR) that were positive for cytomegalovirus (CMV) in patients with keratitis of unknown origin and to investigate their clinical manifestations. DESIGN: Retrospective, interventional case series. PARTICIPANTS: Seventy-eight patients with epithelial (n=37), stromal (n=12), or endothelial keratitis (n=29) of unknown origin examined at the Osaka University Medical Hospital. METHODS: Clinical examination and tears, corneal scrapings, and aqueous humor specimens were evaluated by real-time PCR for CMV. MAIN OUTCOME MEASURES: Quantification of CMV DNA at the diagnosis of each type of keratitis with unknown origin and monitoring during the therapeutic course for CMV-positive cases. RESULTS: No cases of epithelial or stromal keratitis had CMV DNA. Seven of 29 corneal endotheliitis cases (24.1%) were positive for CMV. Cytomegalovirus-positive cases of corneal endotheliitis characterized by localized corneal edema and keratic precipitates included 4 patients who had undergone penetrating keratoplasty and were refractory to the treatment for graft rejection and 3 patients with idiopathic endotheliitis. Cytomegalovirus DNA copy numbers were estimated and ranged from 6.3x10(4) to 3.6x10(6)/ml. In all positive cases, the numbers of CMV DNA copies decreased within weeks during treatment with systemic and topical ganciclovir (GCV) combined with a topical steroid. Five eyes (62.5%) had clinical improvement. In cases of endothelial keratitis, diabetes mellitus was significantly higher in patients positive for CMV (71.4%) than in patients negative for CMV (18.2%, P=0.016, chi-square test). CONCLUSIONS: A total of 24.1% of cases with corneal edema of unknown origin were CMV positive and should be included in the differential diagnosis of idiopathic corneal endotheliitis or graft edema after penetrating keratoplasty, especially for bullous keratopathy. Real-time PCR for CMV, based on the diagnosis and monitoring of the clinical course, may be useful. Cytomegalovirus corneal endotheliitis requires early appropriate treatment using GCV. Because clinical remission after GCV may depend on the area of normal endothelium, early diagnosis and therapy are important for CMV corneal endotheliitis.