Researchers found that IgG antibodies in children with active lupus nephritis (LN) carry abnormal sugar attachments (glycosylation patterns) distinct from those in lupus patients without kidney disease. These aberrant IgG molecules disrupt the energy metabolism of podocytes—specialized kidney filtration cells—by impairing glycolysis, a key ATP-generating pathway. Five specific glycolytic metabolites and the enzyme pyruvate kinase M (PKM) were identified as central to this disruption. Successful treatment normalized IgG glycosylation. Urine analyses confirmed elevated pyruvic acid and PKM expression in podocytes shed from LN patients. These findings suggest IgG glycosylation could serve as an early biomarker for LN and that correcting aberrant glycosylation may protect podocytes from injury.
