Altered in vitro lymphocyte response in childhood nephrotic syndrome

The immune system, and disturbed T lymphocyte function in particular, has previously been implicated in the pathogenesis of childhood idiopathic nephrotic syndrome. As this disorder is commonly responsive to steroid therapy, we set out to determine whether in vitro suppression of lymphocyte blastogenic response to the mitogen phytohaemagglutinin (PHA) could predict the clinical situation. Comparing nine nephrotic children with nine healthy controls we were able to show the inhibitory prednisolone dose that suppressed lymphocyte blastogenesis by 50% (ID50) at a known concentration of PHA was significantly greater (P < 0.005) for nephrotic individuals. However, the in vitro assay did not reliably predict the clinical response to prednisolone. This study further implicates altered lymphocyte function in the mechanisms underlying idiopathic nephrotic syndrome.