Amongst factors influencing the progression of IgA nephropathy (NP), the role of pathological haemorrheological parameters has recently aroused increasing interest. We undertook investigations in order to obtain answers whether IgA NP patients demonstrate haemorrheological changes and if so, what is their association with serum IgA and plasma fibrinogen levels, as well as whether there is any association between pathological haemorrheological parameters and clinical findings.Plasma, whole blood viscosity (p<0.001) and red blood cell (RBC) aggregation (p<0.05) were significantly
higher in patients with IgA NP (n=57), in comparison to healthy controls. We noted positive but low-level significant correlations between plasma viscosity and serum IgA (p<0.05), cholesterol (p<0.05) and triglyceride levels (p<0.01). However, we did not reveal any significant correlation between the plasma's viscosity and plasma fibrinogen. Plasma fibrinogen demonstrated a positive significant correlation with the serum creatinine level (p<0.01), proteinuria (p<0.05) and a negative correlation with the endogenous creatinine clearance (p<0.001). We noted a positive low-level correlation between whole blood viscosity and the endogenous creatinine clearance (p<0.05) and a negative one between whole blood viscosity and the serum creatinine level (p<0.05). IgA NP patients with elevated serum IgA levels (³4.2 g/l, n=23) had significantly elevated serum triglyceride levels (p<0.05), plasma viscosity (p<0.001), RBC aggregation (p<0.05) and a significantly lower endogenous creatinine clearance (p<0.05), in comparison to patients with normal serum IgA levels (<4.2 g/l, n=34). We noted no significant differences between haemorrheological parameters of subgroups with elevated (³4.0 g/l, n=30) and those with normal plasma fibrinogen levels (<4.0 g/l, n=27). Patients with elevated plasma fibrinogen levels presented with a significantly higher proteinuria (p<0.05) and a significantly lower endogenous
creatinine clearance, in comparison to patients with normal plasma fibrinogen levels. Thus, an elevated serum IgA level may have an effect on the progression of IgANP, by increasing plasma and whole blood viscosity. The elevated plasma and whole blood viscosity levels cause vasodilatation of the afferent arterioles resulting in hyperfiltration with the progression of nephropathy. High plasma fibrinogen levels result in poor prognosis, independently of its known rheological effect.

Keywords: Fibrinogen, IgA nephropathy, haemorrheology