title: Circulating antipericyte autoantibodies: a novel modifier of risk of progression of diabetic retinopathy?
abstract: BACKGROUND
  Antipericyte autoantibodies (APAAs) are present in high frequency among diabetic subjects with and without nonproliferative retinopathy. This study aimed to determine whether progression of retinopathy in type 2 diabetes was associated with the same medical risk factors in APAA-positive subjects as in APAA-negative subjects.
  
  
  METHODS
  Type 2 diabetic patients with nonproliferative diabetic retinopathy at baseline were followed prospectively for 2 years monitoring progression of retinopathy. Thirty-eight (21.7%) of 175 patients had progression in Early Treatment Diabetic Retinopathy Study grade by > or =2 steps in at least 1 eye. Serum APAAs were detected by immunofluorescence on tissue-cultured bovine retinal pericytes.
  
  
  RESULTS
  Progression of retinopathy was associated with HbA(1c) level (P = 0.002), diabetes duration (P = 0.03), and albumin/creatinine ratio (P = 0.02) in APAA-negative subjects but not in APAA-positive subjects. The association between progression and APAAs was strongest in the upper quartile for HbA(1c) level (>8.0%), where 71.4% of patients negative for APAAs had progression of retinopathy while only 24.1% of patients positive for APAAs had progression (P = 0.007).
  
  
  CONCLUSIONS
  The results suggest that APAA presence is a modifier of risk of progression of retinopathy due to hyperglycemia and that it could be useful as a biochemical marker of risk of progression of diabetic retinopathy in type 2 diabetic patients with poor metabolic control.
authors.affiliation: University of Arizona College of Medicine, Tucson, Arizona 85724, USA. nayak01@comcast.net
authors.forename: Ramesh C
authors.initials: RC
authors.lastname: Nayak
authors.forename: Kristian
authors.initials: K
authors.lastname: Lynch
authors.forename: Carin
authors.initials: C
authors.lastname: Gustavsson
authors.forename: Michael G K
authors.initials: MG
authors.lastname: Kwok
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Farthing-Nayak
authors.forename: Carl-David
authors.initials: CD
authors.lastname: Agardh
authors.forename: Elisabet
authors.initials: E
authors.lastname: Agardh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D003924:Diabetes Mellitus, Type 2 / Q000276:immunology*; D003930:Diabetic Retinopathy / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D020286:Pericytes / Q000276:immunology*; D011446:Prospective Studies; D015861:Retinal Neovascularization / Q000276:immunology; D012307:Risk Factors
chemical_list: D001323:Autoantibodies; D006442:Glycated Hemoglobin