RESUMEN
A 43-year-old male patient with onset of edema caused by nephrotic proteinuria and low titer of anti-M type phospholipase-A 2-receptor (PLA 2R) antibody was diagnosed as idiopathic membranous nephropathy by renal biopsy. Administrated with prednisone 40 mg once a day and cyclosporine 100 mg twice a day as front-line regimen, the patient relapsed after transient partial remission. When treatment was combined with cyclophosphamide 100 mg once a day, the 24-hour total urine protein and titer of anti-PLA 2R antibody were even elevated. Therefore, the patient received rituximab 1 g intravenously in April 2019, October 2019 and October 2020 respectively. CD19 positive B lymphocytes in peripheral blood were eliminated from 71/μl to zero. Immunosuppressants and corticosteroids were withdrawn successively. On the last follow-up in November 2020, the anti-PLA 2R antibody was negative, and the 24-hour total urine protein and serum albumin was 4.4 g and 34 g/L, respectively. This case suggested the potential efficacy of rituximab for refractory membranous nephropathy. Further studies should explore whether the titer of anti-PLA 2R antibody indicates the dose of rituximab.
RESUMEN
Objective To investigate the different expressions of plasma M type phospholipase A2 receptor antibody and IgG subtypes deposition of kidney tissues in idiopathic membranous nephropathy and hepatitis B virus-associated membranous nephropa-thy,and to evaluate the significance of plasma M type phospholipase A2 receptor antibody and IgG subtypes in diagnosis of hepatitis B virus-associated membranous nephropathy.Methods Plasma samples were obtained from patients with idiopathic membranous nephropathy,hepatitis B virus-associated membranous nephropathy and minimal change disease,respectively,before immunosup-pressive therapy.Concentration of plasma M type phospholipase A2 receptor antibody was detected by sandwich ELISA and concen-tration of IgG subtypes were measured by immunofluorescence.Results Concentration of plasma M type phospholipase A2 receptor antibody was (15.4±7.2)μg/mL in idiopathic membranous nephropathy group,higher than that in the hepatitis B virus-associated membranous nephropathy group (10.3±5.7)μg/mL (P <0.01),between idiopathic membranous nephropathy group and hepatitis B virus-associated membranous nephropathy group.There was no distinct difference of IgG subtypes deposition in glomerlar capil-lary wall.Conclusion There is obvious clinical significance of concentration of plasma M type phospholipase A2 receptor antibody in differential diagnosis of idiopathic membranous nephropathy and hepatitis B virus-associated membranous nephropathy,while no distinct significance of IgG subtypes deposition.