Association Between SNP of SP-D and Susceptibility and Prognosis of Infectious Keratitis

Study Overview
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Brief Summary
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This study explores the association between single nucleotide polymorphism (Met11Thr) of surfactant protein D(SP-D) and susceptibility and prognosis of infectious keratitis.Met11Thr of SP-D of patients with keratitis and normal controls were compared.Allele and genotype frequencies of patients with keratitis and normal controls were determined by polymerase chain reaction with sequence specific primers(PCR-SSPs) .SP-D gene polymorphism of patients with keratitis and normal controls was detected by Sanger sequencing

Detailed Description
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Surfactant protein D(SP-D) plays an important role in the innate immune system of the eye in the lacrimal duct, cornea and conjunctiva.The single lipopolysaccharide on the surface of bacteria and the receptors on the surface of immune cells are linked by SP-D ,which acts as a bridge to neutralize viruses in the innate immune defense system and assists other immune cells in clearing bacteria and fungi.SP-D can also participate in the acquired immune response after combining with lipopolysaccharide on the surface of microorganisms.Some single nucleotide polymorphisms of SP - D can not only affect the plasma level of SP - D, which leads to the differences of pathogen defense capability, but also can affect the space configuration and structure of carbohydrate recognition domain of SP-D, causing the change of ability of SP - D combined with pathogens to influence its defensive role.The concentration of SP - D in ocular surface is closely related to the occurrence and progression of infectious keratitis.Association between single nucleotide polymorphisms of SP-D and the occurrence and development of infectious keratitis has yet to be confirmed by research.

Official Title
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Consecutive, Case Control Study of Association Between Single Nucleotide Polymorphism of SP-D and Susceptibility and Prognosis of Infectious Keratitis

Conditions
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Infectious Keratitis

Intervention / Treatment
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* Drug: Treatment of bacterial keratitis
* Drug: Treatment of fungal keratitis
* Drug: Treatment of viral keratitis
* Diagnostic Test: corneal scraping
* Other: Sequencing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical diagnosis of Infectious Keratitis. Laboratory diagnosis of Infectious Keratitis. Exclusion Criteria: Patients with topical or systemic long-term use of hormones, interferon, or immunosuppressive therapy. Patients with basic diseases such as diabetes, autoimmune disease, sjogren's syndrome, blepharitis, eyelid defect or incomplete eyelid closure. Patients with history of corneal myopia laser, cataract surgery and vitrectomy, or history of serious ocular trauma and drug allergies.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Control Group<br>health volunteers | Other: Sequencing<br>* polymerase chain reaction with sequence specific primers(PCR-SSP) and Sanger sequencing<br>|
| Infectious Keratitis Group<br>Infectious corneal patients | Drug: Treatment of bacterial keratitis<br>* 0.3% Levofloxacin Eye Drops or 0.3% Tobramycin Eye Drops QID<br>Drug: Treatment of fungal keratitis<br>* 1% Fluconazole Eye Drops or 0.25% Amphotericin B Eye Drops QID<br>Drug: Treatment of viral keratitis<br>* 0.1% Acyclovir eye drops QID ，Ganciclovir gel QN，Famiclovir tablets 0.25g TID<br>Diagnostic Test: corneal scraping<br>* culture and sensitivity of corneal ulcerated infiltrating edge tissue<br>Other: Sequencing<br>* polymerase chain reaction with sequence specific primers(PCR-SSP) and Sanger sequencing<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Base type | Base type of SNP（rs721917）:(Met and Thr) | before the treatment | 
| Genotype | Genotype of SNP（rs721917）:( Met /Met , Thr/Thr and Met/Thr) | before the treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Grading of Keratitis | Grading of Keratitis： cornea:transparency ,edema,turbidity,perforation conjunctiva: hyperaemia blephar:inflammation | before the treatment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Infectious Keratitis, surfactant protein D, single nucleotide polymorphisms, Met11Thr, rs721917