Alpaca Anti-Mouse IgG1 Fc monoclonal Antibody, clone WII413 [Alexa Fluor®647]

Our patient was a 69-year-old woman admitted to our hospital for heavy proteinuria and hematuria. A renal biopsy showed findings similar to those of membranoproliferative glomerulonephritis associated with nodular lesions, and immunofluorescence showed marked deposits of IgG, C1q, and C3 on the peripheral capillary walls. IgG3 alone was observed on IgG subclass staining with no kappa or lambda light chains, and Congo red staining was negative. These findings suggested IgG3-heavy-chain deposition disease (HCDD). However, we did not find a deletion of the first heavy-chain constant domain, which is commonly observed in HCDD. Electron microscopy showed randomly arranged subendothelial microtubular structures with diameters of 70-90 nm. Altogether, the diagnosis of HCDD could not be made, although monoclonal IgG3 deposits in glomeruli were observed. This is the first case report of monoclonal IgG3-heavy-chain glomerulonephritis with subendothelial-based, randomly arranged microtubular structures with diameters of 70-90 nm.

The Impella device is a percutaneous ventricular assist devices that requires administration of heparin via a continuous purge solution. Patients on Impella device support may experience hemolysis with accompanying thrombocytopenia generating suspicion for heparin-induced thrombocytopenia (HIT). However, data and recommendations for use of non-heparin anticoagulants with Impella device are lacking. Therefore, we performed a retrospective cohort analysis of patients requiring bivalirudin during Impella device support to describe the safety and efficacy of bivalirudin as an alternative anticoagulant during Impella device support. Nine patients were included in the evaluation which analyzed Impella device purge flow and purge pressure along with bivalirudin dosing requirements, incidence of thrombosis, and incidence of pump failure. All patients had a positive platelet factor-4 IgG ELISA test, and the serotonin release assay was positive in four patients. After initiation of bivalirudin, the median (15th, 85th percentile) nadir purge flow decreased by 76% (5%, 88%) and the median (15th, 85th percentile) peak purge pressure increased by 86% (21%, 143%). At the time of bivalirudin discontinuation, the median final purge flow and pressure were 2.4 mL/h (74% decrease) and 969 mmHg (89% increase), respectively. Zero patients experienced catastrophic pump failure. Adding low concentration bivalirudin to the purge solution along with systemic bivalirudin may be a reasonable approach.