Immunoblot of aminophenylboronic acid (APB)-purified proteins (5 μg/lane) from the immune complexes of patient and control representatives of North American Indian (NAI) or Caucasian (C) descent probed with anti-κ antibodies. Lane 1, Molecular weight markers; lane 2, NAI normal; lane 3, NAI RA anti-advanced glycation end-product (AGE)-negative; lane 4, NAI RA anti-AGE+ lane 5, C normal; lane 6, C RA anti-AGE−; lane 7, C RA, anti-AGE+ lane 8, C diabetic.