Serum anti-collagen type IV IgM antibodies and development of diabetic nephropathy in diabetics with essential hypertension.

INTRODUCTION AND AIMS: Arterial hypertension and diabetic vascular complications are connected with an elevated degradation of elastic tissue. This process leads to an increased production of antibodies to collagen type IV (ACIV Abs). In the present investigation we studied whether the serum levels of antibodies (IgG, IgM and IgA) to collagen are related with microvascular complications.

MATERIAL AND METHODS: Serum levels of antibodies to collagen type IV (ACIV) IgG, IgM and IgA were measured using an ELISA method in 93 patients with type 2 diabetes mellitus and arterial hypertension (AH) (mean age 61.4 ±11.3 years, diabetes duration 9.88 ±3.12 years; hypertension duration 9.28 ±4.98). These values were compared to serum antibodies to CIV in 42 age and sex matched controls.

RESULTS: ACIV IgM antibodies levels in patients with AH and T2DM were statisticaly significantly higher than controls 0.178 (0.145÷0.220) vs. 0.142 (0.118÷0.173) (KW = 6.31; p = 0.01). Group 1 (patients with microvascular complications) showed significantly higher levels of ACIV IgM than controls 0.180 (0.136÷0.223) vs. 0.142 (0.118÷0.173) (KW = 5.03; p = 0.02). Patients from Group 2 showed statistically significantly higher levels of ACIV IgM than controls 0.176 (0.151÷0.202) vs. 0.142 (0.118÷0.173) (KW = 6.15; p = 0.01). ACIV IgM antibodies showed correlation with microalbuminuria (r = 0.21); (p = 0.04), BMI (r = 0.19); (p = 0.04), creatinine clearance (r = -0.36); (p = 0.01) and GFR (r = -0.34); (p = 0.02).

CONCLUSIONS: Our study showed an association between elevation of serum levels of ACIV IgM and development of diabetic nephropathy. We suggest that levels of ACIV IgM can be useful method for identfying a high risk for development of diabetic nephropathy.