Material and methods
Study population
In this cross-sectional study, 13 patients with biopsy-verified IgAN and
13 patients with autosomal dominant polycystic kidney disease (ADPKD),
as disease controls were recruited. The IgAN and ADPKD patients were
matched for kidney function (estimated glomerular filtration rate, eGFR,
±10 ml/min/1.73 m2), gender and age (±10 years). All
study participants were recruited from the Department of Nephrology at
Danderyd University Hospital in Stockholm, Sweden, and submitted written
informed consent. Patients did not have any intercurrent illnesses and
had stable treatment (i.e. no change in dose of angiotensin converting
enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) within
eight weeks from sampling). None of the IgAN patients had a history of
macroscopic hematuria. Proteinuria was measured as urine albumin
creatinine ratio (UACR). Exclusion criteria were ongoing treatment with
systemic corticosteroids or other systemic immunosuppressive drugs,
treatment with systemic corticosteroids within six months from sample
draft, diabetes mellitus, neoplasms or other inflammatory diseases.
Healthy controls (HC) (n = 13) were recruited by announcement and
were gender- and age-matched (±5 years) with IgAN patients. Demographic
characteristics of participants are presented in Table 1.