Objective:To explore the characteristics of serum galactose-deficient IgA1 (Gd-IgA1) and Gd-IgA1/IgA ratio in normal children.Methods:The children from a kindergarten and 3 primary or secondary schools in Baoding (Hebei Province) from March to August 2023 were included in the cross-sectional study.According to their age, the children were divided into the 3-6-year-old group, >6-11-year-old group, and >11-16-year-old group.Besides, some adults were also included as the control group.The immunoturbidimetric assay was used to detect serum IgA levels, and the enzyme-linked immunosorbent assay (ELISA) was employed to detect Gd-IgA1 and Gd-IgA1/IgA levels.The above indicators were subject to normal distribution tests and analysis of variance (ANOVA)or rank sum test.Results:A total of 136 normal subjects were included for analysis.Among these subjects, there were 64 males and 72 females.There were 13 children in the 3-6-year-old group, 51 children in the >6-11-year-old group, and 56 children in the >11-16-year-old group.Besides, 16 normal adults (28-45 years old) from the physical examination center were also included as the control group.The serum IgA levels of the 3-6-year-old group, >6-11-year-old group, >11-16-year-old group, and adult group were (0.88±0.35) g/L, (1.38±0.65) g/L, (1.78±0.61) g/L, and (2.49±0.94) g/L, respectively.Except for no statistically significant difference between the 3-6-year-old group and the >6-11-year-old group, as well as between the >11-16-year-old group and the adult group, all other age groups showed statistically significant differences in serum IgA levels (all P<0.05).The serum Gd-IgA1 levels of the 3-6-year-old group, >6-11-year-old group, >11-16-year-old group, and adult group were 7.77(5.77, 16.51) μg/L, 7.12(5.29, 9.82) μg/L, 8.96(6.21, 14.30) μg/L, and 9.39(6.63, 40.00) μg/L, respectively, with statistically significant differences ( H=9.22, P=0.027).There was no significant difference in the Gd-IgA1/IgA ratio among different groups ( P=0.130).The correlation analysis suggested that Gd-IgA1/IgA1 did not correlate with age ( r=0.134, P=1.200).The Gd-IgA1 level was positively correlated with the IgA level ( r=0.204, P=0.017).There was no significant difference in serum IgA, Gd-IgA1, and Gd-IgA1/IgA levels between different gender groups. Conclusions:There are differences in Gd-IgA1 levels among different age groups among these children, but Gd-IgA1/IgA is not correlated with age.As a diagnostic biomarker, Gd-IgA1 should be emphasized from the different levels among different age groups, while Gd-IgA1/IgA seems to be more convenient for clinical research and application.

Objective:To explore the characteristics of serum galactose-deficient IgA1 (Gd-IgA1) and Gd-IgA1/IgA ratio in normal children.Methods:The children from a kindergarten and 3 primary or secondary schools in Baoding (Hebei Province) from March to August 2023 were included in the cross-sectional study.According to their age, the children were divided into the 3-6-year-old group, >6-11-year-old group, and >11-16-year-old group.Besides, some adults were also included as the control group.The immunoturbidimetric assay was used to detect serum IgA levels, and the enzyme-linked immunosorbent assay (ELISA) was employed to detect Gd-IgA1 and Gd-IgA1/IgA levels.The above indicators were subject to normal distribution tests and analysis of variance (ANOVA)or rank sum test.Results:A total of 136 normal subjects were included for analysis.Among these subjects, there were 64 males and 72 females.There were 13 children in the 3-6-year-old group, 51 children in the >6-11-year-old group, and 56 children in the >11-16-year-old group.Besides, 16 normal adults (28-45 years old) from the physical examination center were also included as the control group.The serum IgA levels of the 3-6-year-old group, >6-11-year-old group, >11-16-year-old group, and adult group were (0.88±0.35) g/L, (1.38±0.65) g/L, (1.78±0.61) g/L, and (2.49±0.94) g/L, respectively.Except for no statistically significant difference between the 3-6-year-old group and the >6-11-year-old group, as well as between the >11-16-year-old group and the adult group, all other age groups showed statistically significant differences in serum IgA levels (all P<0.05).The serum Gd-IgA1 levels of the 3-6-year-old group, >6-11-year-old group, >11-16-year-old group, and adult group were 7.77(5.77, 16.51) μg/L, 7.12(5.29, 9.82) μg/L, 8.96(6.21, 14.30) μg/L, and 9.39(6.63, 40.00) μg/L, respectively, with statistically significant differences ( H=9.22, P=0.027).There was no significant difference in the Gd-IgA1/IgA ratio among different groups ( P=0.130).The correlation analysis suggested that Gd-IgA1/IgA1 did not correlate with age ( r=0.134, P=1.200).The Gd-IgA1 level was positively correlated with the IgA level ( r=0.204, P=0.017).There was no significant difference in serum IgA, Gd-IgA1, and Gd-IgA1/IgA levels between different gender groups. Conclusions:There are differences in Gd-IgA1 levels among different age groups among these children, but Gd-IgA1/IgA is not correlated with age.As a diagnostic biomarker, Gd-IgA1 should be emphasized from the different levels among different age groups, while Gd-IgA1/IgA seems to be more convenient for clinical research and application.