Mannose-binding lectin as part of the complement pathway: characterization in non-inflamed and inflamed human eyes.

Abstract

BACKGROUND:

Mannose-binding lectin plays a central effector role in the lectin pathway of complement activation. Frequently occurring MBL2 polymorphisms result in mannose-binding lectin deficiency, which increases susceptibility to infection. We characterized mannose-binding lectin levels and function in non-inflamed and inflamed human eyes, and evaluated its relationship to blood mannose-binding lectin levels and function.

DESIGN:

Prospective, observational clinical study with controls and cases.

PARTICIPANTS:

Twenty-seven patients with paired blood and ocular samples (aqueous and/or vitreous) including 15 controls (non-inflamed) and 12 cases (inflamed).

METHODS:

Blood and ocular samples were collected from controls (n = 15) with quiet eyes during elective cataract surgery and cases with inflamed eyes including proven/suspected endophthalmitis (n = 11) and herpetic retinal vasculitis (n = 1). Mannan-binding and C4 deposition enzyme-linked quantify mannose-binding lectin levels and function.

MAIN OUTCOME MEASURES:

Blood and ocular mannose-binding lectin levels and function.

RESULTS:

Of 27 patients, 10 (37%) were mannose-binding lectin-deficient (defined as blood mannose-binding lectin levels <500 ng/mL). Blood mannose-binding lectin levels (P= 0.16) or function (P= 0.43) were not significantly different between controls and cases. As expected, there was a high correlation between blood mannose-binding lectin levels and function (r(2) = 0.74). However, there was significantly more mannose-binding lectin in inflamed eyes than non-inflamed eyes measured as level (P < 0.01) or C4 deposition function (P < 0.01).

CONCLUSIONS:

Our study demonstrated that mannose-binding lectin is significantly elevated in inflamed human eyes but virtually undetectable in non-inflamed control eyes, suggesting a role in sight-threatening ocular inflammation.

• Authors: Sing-Pey Chow, Melinda M Dean, Jozef A Depla, Mark D Daniell, Damon P Eisen
• Journal: Clinical & experimental ophthalmology (Clin Exp Ophthalmol) Vol. 39 Issue 9 Pg. 871-7 (Dec 2011) ISSN: 1442-9071 [Electronic] Australia
• PMID: 21631672 (Publication Type: Journal Article)
• Copyright: © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.

Chemical References

• Complement C4
• Mannose-Binding Lectin

Topics

• Adult
• Aged
• Aged, 80 and over
• Cataract (blood)
• Cataract Extraction
• Complement C4 (metabolism)
• Complement Pathway, Mannose-Binding Lectin (physiology)
• Endophthalmitis (blood, microbiology)
• Enzyme-Linked Immunosorbent Assay
• Female
• Humans
• Inflammation (blood)
• Male
• Mannose-Binding Lectin (blood)
• Prospective Studies
• Retinal Vasculitis (blood, virology)
• Young Adult