Asymmetric depression in the serum level of IgG subclasses in patients with nephrotic syndrome.

Thirty-three nephrotic patients were studied for IgG-subclass levels in matched pairs of serum and urinary specimens. Levels in the serum were compared with those found in the sera of non-nephrotic control children and normal adults. Results have shown an asymmetric depression in the serum level of certain IgG subclasses in some patients with minimal-change nephrotic syndrome, focal glomerulosclerosis, and proliferative glomerulonephritis, indicating that the urinary loss of IgG alone cannot account for the low blood levels of this immunoglobulin class in these conditions.