Aberrant galactosylation of IgA1 is involved in the genetic susceptibility of Chinese patients with IgA nephropathy.
BACKGROUND
Immunoglobulin A nephropathy (IgAN) is associated with genetic and environmental factors, and undergalactosylation of IgA1 in the serum is considered to be a contributor to pathogenesis of IgAN. The present study was conducted to detect the galactose- (Gal) deficient IgA1 level in Chinese IgAN patients and their family members.


METHODS
Sixty-three IgAN patients were enrolled, where 32 first-degree relatives of 19 patients and 44 spouses of 44 patients were recruited. Healthy blood donors (n = 39) were used as normal controls. Biotinylated HAA (Helix aspersa) was utilized to detect the Gal-deficient IgA1 in enzyme-linked immunosorbent assay (ELISA). All the results were corrected by serum IgA1 concentration.


RESULTS
Compared with normal controls, the sera IgA1 of patients and their first-degree relatives demonstrated increased Gal-deficient IgAl level (0.17 +/- 0.09 versus 0.10 +/- 0.04, P = 0.001; 0.14 +/- 0.07 versus 0.10 +/- 0.04, P = 0.028); no significant difference between patients and their first-degree relatives was detected (0.17 +/- 0.09 versus 0.14 +/- 0.07, P = 0.127). In contrast, serum Gal-deficient IgA1 level of IgAN patients was higher than their counterpart spouses and normal controls (0.18 +/- 0.13 versus 0.14 +/- 0.09, P = 0.009; 0.18 +/- 0.13 versus 0.10 +/- 0.04, P = 0.001), while that of patients' spouses was comparable with normal controls (0.14 +/- 0.09 versus 0.10 +/- 0.04, P = 0.075). There was no correlation between clinicopathological data and serum Gal-deficient IgA1 level.


CONCLUSIONS
The patients with IgAN and their first relatives showed significant higher Gal-deficient IgA1 level than healthy controls, whereas patients' spouses were the same as healthy controls. It can be suggested that the Gal-deficient IgA1 might be inherited in Chinese patients with IgAN.
Lin
Xiaojie
X
Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology and Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, People's Republic of China.
Ding
Jiaxiang
J
Zhu
Li
L
Shi
Sufang
S
Jiang
Lei
L
Zhao
Minghui
M
Zhang
Hong
H
D000328:Adult; D005260:Female; D005690:Galactose / Q000378:metabolism*; D005803:Genes, Immunoglobulin; D020022:Genetic Predisposition to Disease; D005922:Glomerulonephritis, IGA / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism*; D008297:Male
D007070:Immunoglobulin A; D005690:Galactose