Watanabe Shojiro, Tsugawa Koji, Tsuruga Kazushi, Imaizumi Tadaatsu, Tanaka Hiroshi
Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan.
Department of Vascular Biology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
Pediatr Int. 2017 Oct;59(10):1112-1115. doi: 10.1111/ped.13355.
Rituximab (RTX), a specific antibody to human CD20, has been successfully used to treat intractable nephrotic syndrome (NS). Recent studies have suggested a direct effect of RTX on podocytes by targeting sphingomyelinase phosphodiesterase acid-like 3b (SMPDL-3b). Thus, we examined the urinary excretion of SMPDL-3b as well as its immunoreactivity in biopsy specimens from children with intractable NS. Urine samples from six patients (five with minimal-change NS and one with focal segmental glomerulosclerosis) and from four healthy adults were examined. Glomerular immunoreactivity and urinary excretion of SMPDL3b in proteinuric NS patients decreased compared with controls. Interestingly, urine samples obtained from the same patients at the remission stage after RTX treatment showed an increase in urinary SMPDL-3b excretion compared with the proteinuric stage. Urinary excretion level of SMPDL-3b could thus be used to predict the clinical efficacy of RTX treatment in NS patients.
利妥昔单抗（RTX）是一种针对人CD20的特异性抗体，已成功用于治疗难治性肾病综合征（NS）。最近的研究表明，RTX通过靶向酸性鞘磷脂磷酸二酯酶样3b（SMPDL-3b）对足细胞有直接作用。因此，我们检测了难治性NS患儿活检标本中SMPDL-3b的尿排泄情况及其免疫反应性。检测了6例患者（5例微小病变型NS和1例局灶节段性肾小球硬化症患者）以及4名健康成年人的尿液样本。与对照组相比，蛋白尿性NS患者的肾小球免疫反应性和SMPDL3b的尿排泄量降低。有趣的是，在RTX治疗后缓解期从同一患者获得的尿液样本显示，与蛋白尿期相比，尿SMPDL-3b排泄量增加。因此，SMPDL-3b的尿排泄水平可用于预测RTX治疗NS患者的临床疗效。
