Nephrological factors may cause kidney dysfunction in patients with common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous primary deficiency characterized by hypogammaglobulinemia, recurrent infections, an increased risk of autoimmune disease, malignancy, and chronic inflammation. Proteinuria is one of the most important prognostic factors causing progression in kidney disease. Proteinuria causes tubulotoxicity, activates inflammatory markers that cause fibrosis, and consequently nephropathy progression. The data is scant in the literature regarding the inflammation and nephropathy in CVID. Hence, in the present study, we aimed to investigate the relationship between tubular dysfunction, proteinuria, and inflammation in patients with CVID.

This was a cross-sectional study involving 27 patients with CVID (15 females, 12 males; mean age, 39.88 ± 13.47 years) and 18 control subjects (10 females, 8 males; mean age, 33.83 ± 7.97 years). Patients were evaluated for kidney functions including glomerular filtration rate, fractional excretion of sodium, metabolic acidosis, serum/urine anion gap, 24-h urine proteinuria and, were grouped in terms of proteinuria. Blood samples obtained from the patients with CVID were taken into 2 mL EDTA tube to evaluate peripheral NK cell subgroups according to CD56 and CD16 expression and CD3, CD4, CD 8 expression to determine subtypes T cells. These cells were evaluated by flow cytometry technique.

Urinary density, fractional excretion of sodium, proteinuria, and metabolic acidosis are found to be higher in patients with CVID when compared to healthy controls. In the bivariate correlation analysis, proteinuria was positively correlated with age (r = 0.496, p = < 0.001), CD8+T cells percentage (r = 0.427, p = 0.02). Albumin, CRP, and CD8+T cell percentage were found to be independent variables of proteinuria.

Increased chronic ongoing inflammation was found to be associated with proteinuria in patients with CVID. Hence, in routine outpatient clinics, proteinuria should not be overlooked in this group of patients.