A Case of NCAM1-Positive Lupus Nephritis with NCAM1 Antibody Titers Responsive to Rituximab.

Neural cell adhesion molecule 1 (NCAM1) is a recently identified new antigen of membranous nephropathy (MN) mostly secondary to systemic lupus erythematosus with a low positive rate of 6.6%, and its corresponding antibody was detected in patients' sera. Here, we reported a case of NCAM1-positive lupus nephritis (class V+III) developed from MN. The patient was refractory to multiple immunosuppressive regimens but achieved remission after the application of rituximab as an add-on therapy and showed a reduction of anti-NCAM1 antibody and proteinuria.