The level of urinary semaphorin3A is associated with disease activity in patients with minimal change nephrotic syndrome.

Semaphorin3A is a secreted protein known to be involved in organogenesis, immune responses and cancer. In the kidney, semaphorin3A is expressed in the glomerular podocytes, distal tubules and collecting tubules, and believed to play a role in the regulation of the kidney development and function. We examined the serum and urinary semaphorin3A levels in 72 patients with renal disease and 5 healthy volunteers. The patients had been diagnosed with thin basement membrane disease (n=4), minimal change nephrotic syndrome (MCNS; n=22), IgA nephritis (n=21), membranous nephropathy (n=16) and focal segmental glomerular sclerosis (n=9). The level of urinary semaphorin3A in MCNS patients tended to be relatively high among all disease groups. We also investigated the urinary semaphorin3A level in 7 patients with MCNS from disease onset to remission during the drug therapy. MCNS patients in pre-remission states had higher urinary semaphorin3A levels than those in post-remission states receiving immunosuppressive therapies. These results suggested that the urinary semaphorin3A level correlates with the MCNS activity. Semaphorin3A has the potential as a biomarker for MCNS to clarify the reactivity for therapy and may be useful in examining other glomerular diseases with proteinuria as well.