First Report in the Literature of Biopsy-Proven Noncollapsing Focal Segmental Glomerulosclerosis Relapse in a Second Renal Transplant Presenting With Thrombotic Microangiopathy: A Case Report.

Primary focal segmental glomerulosclerosis (FSGS) is a podocytopathy with an irregular response to immunosuppressive therapies. FSGS relapse occurs in 30% to 80% of kidney grafts, and poor survival outcomes include large proteinuria and the nephrotic syndrome's cardinal clinical features. Thrombotic microangiopathy (TMA) is caused by endothelial injury due to complement dysregulation including acute kidney injury, proteinuria, and severe hypertension common renal presentations. Both pathologies have well-described genetic forms, but their relationship remains uncertain. FSGS lesions can be found in kidney biopsy specimens in patients with TMA, and TMA has been reported in patients with collapsing glomerulopathy. However, this combination has not been clearly described in renal transplant recipients. We present the case of a 22-year-old man who received his second kidney allograft and developed an early graft disfunction with nephrotic syndrome and clinical TMA. His background was remarkable for primary, biopsy-confirmed FSGS in childhood, and he started hemodialysis in 2006 and received a living donor kidney graft the same year. He presented with a FSGS relapse with malignant hypertension and seizures in the first posttransplant month and had an irregular response to plasma exchange and rituximab, and dialysis was reinitiated 10 years later. A total of 3 biopsies were performed after his second kidney transplant showing the evolution of a FSGS relapse with histologic and clinical TMA in the absence of identified genetic mutations. Partial responses to treatments with plasma exchange, eculizumab, and rituximab were obtained, but the allograft was lost after 26 months. This case is the first report of concomitant FSGS and TMA in a renal transplant recipient.

Case Report: Successful Response to Intravenous Immunoglobulin and Steroid Pulses in a Renal Transplant Recipient With Severe Covid-19 Disease and Associated Acute Allograft Failure.

The impact of Covid-19 pneumonia caused by SARS-CoV-2 on transplanted populations under chronic immunosuppression seems to be greater than in normal population. Clinical management of the disease, particularly in those patients worsening after a cytokine storm, with or without allograft impairment and using available therapeutic approaches in the absence of specific drugs to fight against the virus, involves a major challenge for physicians. We herein provide evidence of the usefulness of high-dose intravenous immunoglobulin (IVIG) combined with steroid pulses to successfully treat a case of Covid-19 pneumonia in a single-kidney transplanted patient with mechanical ventilation and hemodialysis requirements in the setting of a cytokine storm. A rapid decrease in the serum level of inflammatory cytokines, particularly IL-6, IL-8, TNF-α, MCP-1 and IL-10, as well as of acute-phase reactants such as ferritin, D-dimer and C-reactive protein was observed after the IVIG infusion and methylprednisolone bolus administration with a parallel clinical improvement and progressive allograft function recovery, allowing the patient's final discharge 40 days after the treatment onset. The immunomodulatory effect of IVIG together with the anti-inflammatory and immunosuppressive potential of steroids could be an alternative strategy to treat severe cases of Covid-19 pneumonia associated with an uncontrolled inflammatory response in transplanted populations.