Podocyte infolding glomerulopathy; report of the first case in Latin America and review of the literature. / Glomerulopatía por invaginación podocítica; reporte del primer caso en Latinoamérica y revisión de la literatura.

BACKGROUND: Podocyte infolding glomerulopathy (PIG) is a condition of uncertain origin, frequently associated with autoimmune diseases. Its specific treatment and clinical course are unknown. It is characterised by thickening of the capillary walls due to the presence of non-argyrophilic intramembranous bubbles similar to those found in membranous glomerulopathy, but without electron-dense deposits of immune complexes in the ultrastructure, where translucent microspheres generated by invagination of the podocyte cytoplasm into the basement membranes are observed. OBJECTIVES: Generally reported in young females patients. To date, few cases in Asian patients have been reported. Our case is the first to be reported in a Latin American Caucasian patient. METHODS: A 38-year-old woman with SLE. In 2014 she presented with nephrotic syndrome empirically treated with corticosteroids (CO) and intravenous cyclophosphamide with good response. She had a relapse in April 2015 with normal renal function and no extrarenal lupus activity, so she was referred to our hospital to be biopsied. RESULTS: The biopsy reported focal segmental glomerular sclerosis without deposits of immune complexes in the immunofluorescence. However, methenamine silver staining revealed clear spaces in the capillary walls accompanied by marked podocyte alterations. On electron microscope study, numerous aggregates of microvesicular and cylindrical ultrastructures bound to the membranes were observed, without evidence of dense deposits, and diffuse effacement of pedicel foot processes, confirming the suspected diagnosis. CONCLUSIONS: This is the first reported case of what can be considered a new pathological glomerular entity in a Latin American Caucasian patient, whose clinical course and therapy are still unknown.

Kidney biopsy-based management of maintenance immunosuppression is safe and may ameliorate flare rate in lupus nephritis.

The optimal duration of maintenance immunosuppressive therapy for patients with lupus nephritis who have achieved clinical remission has not been established. Furthermore, clinical and histologic remissions are often discordant. We postulated that continuing therapy for patients with persistent histologic activity on kidney biopsies done during maintenance and discontinuing therapy only for patients without histologic activity would minimize subsequent lupus nephritis flares. To test this, a cohort of 75 prospectively-followed patients with proliferative lupus nephritis was managed using kidney biopsies performed during maintenance therapy. These patients had been on immunosuppression for at least 42 months, had responded, and had maintained their clinical response for at least 12 months before the kidney biopsy was repeated. Maintenance therapy was withdrawn if the biopsy showed an activity index of zero, but was continued if the biopsy showed an activity index of one or more. A lupus nephritis flare developed in seven patients during the average 50 months from the third biopsy and the final clinic visit for a flare rate of 1.5/year; significantly less than reported flare rates. Baseline clinical parameters (serum creatinine, proteinuria) and serologic parameters (complement C3, C4 and anti-dsDNA) did not predict an activity index of zero on the third biopsy or who would have a lupus nephritis flare. No patients developed end-stage kidney disease. Four patients developed de novo chronic kidney disease. There were no serious adverse events related to biopsy. Thus, at an experienced center, biopsy-informed management of maintenance immunosuppression is safe and may improve the lupus nephritis flare rate compared to conventional clinical management.