Reduced serum uric acid levels in neuromyelitis optica: serum uric acid levels are reduced during relapses in NMO

Objectives Uric acid ( UA ), a product of purine metabolism, is known to be reduced in patients with various neurological disorders including multiple sclerosis ( MS ). However, it has still remained unclear whether there is a close relationship between UA and neuromyelitis optica ( NMO ). The aim of this study was to investigate the association between serum UA levels and disease activity in NMO . Methods Retrospective analysis was made of blood samples during relapses ( n  =   48) and during stable disease ( n  =   49) from 20 patients with NMO . As controls, 59 blood samples during relapses from 39 patients with MS and 90 samples from healthy subjects were obtained. Spine magnetic resonance images ( MRI s) performed during relapses ( n  =   24) in NMO were analysed. Results The results indicated that UA levels during relapses in NMO were significantly lower compared to healthy subjects ( P   <   0.01), but not different from those during relapses in MS , and that reduced UA levels during relapses in NMO were normalized during stable disease. However, UA levels during relapses were not correlated with G d enhancement in spine MRI . Conclusion UA levels are associated with clinical disease status in patients with NMO . Further investigations are recommended to elucidate the role of UA as a biomarker of disease activity in NMO .