Higher serum levels of autotaxin and phosphatidylserine-specific phospholipase A 1 in patients with lupus nephritis

Recent studies revealed that lysophospholipids (LPLs) and related molecules, such as autotaxin (ATX) and phosphatidylserine-specific phospholipase A (PS-PLA ), are candidates for novel biomarkers in melanoma, glaucoma and diabetic nephropathy. However, it is not clear whether serum levels of ATX/ PS-PLA would be associated with pathological and clinical findings of lupus nephritis (LN). In this retrospective cohort study, serum samples were collected from 39 patients with LN and 37 patients with other glomerular diseases. The serum levels of ATX and PS-PLA were evaluated for an association with renal pathology and clinical phenotypes of LN. The serum levels of ATX and PS-PLA were higher in the patients with LN as compared to those with other glomerular diseases. Among the classes of LN, the patients with class IV showed the trend of lower serum levels of ATX. Moreover, the patients with lower levels of ATX exhibited higher scores of activity index (AI) and chronicity index (CI). The level of ATX tended to be negatively correlated with AI and CI. These results might be explained by the effect of treatment, because the serum levels of ATX and PS-PLA were inversely correlated with the daily amount of oral prednisolone. Moreover, they did not reflect the level of proteinuria or kidney survival in LN patients. Although the serum levels of ATX and PS-PLA were affected by the treatment, these levels were higher in the patients with LN. The potential clinical benefits of these markers need to be clarified in further studies.