case_images: PMC11309753_01
case_images: Course of the successful treatment of a 47-year-old man suffering from a biopsy-confirmed primary immune complex-MPGN with the complement factor B inhibitor iptacopan. For the dosage of medication, refer to the text. MPGN, membranoproliferative glomerulonephritis; UPCR, urine protein-creatinine ratio; RAS, renin-angiotensin-system.
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case_images: PMC11309753_01_cnd-2024-0014-0001-540013_F02.jpg
case_images: F2
case_images: Urine protein-creatinine ratio (UPCR) was 171 mg/mmol (reference range <11 mg/mmol) which peaked to 372 mg/mmol at the time of kidney biopsy which was performed soon after the first presentation (Fig. 2). During steroid treatment, the patient suffered from serious side effects (i.e., severe inner restlessness, accompanied by insomnia and difficulty concentrating so that he could hardly work, further increasingly hypertensive blood pressure, weight gain, edema, and leg pain), therefore other immunosuppressive regimens were established as the disease was not under control (summarized in Fig. 2). Finally, mycophenolate mofetil (MMF) therapy was started at a dosage of 1,000 mg BID in November 2018 (for details, see Fig. 2). Nevertheless, in December 2022 another severe flare of the disease occurred with heavy proteinuria in the nephrotic range (Fig. 2). Three months after starting the treatment with iptacopan UPCR decreased impressively to a level of 100-150 mg/mmol and kidney function return to his baseline level (Fig. 2). Thereafter, proteinuria at a low level and kidney function remained stable during follow-up (Fig. 2).
case_images: Histopathological findings. a By light microscopy, the glomeruli showed a prominent lobular architecture with increased mesangial and intracapillary cellularity (black arrow). The peripheral glomerular basement membranes focally showed double contours (red arrow). There were also several segmental scleroses (white arrow), PAS-staining, x200. By immunofluorescence, there was diffuse global granular deposition of C3 (b) and IgG (c) (immunofluorescence, x400). d By electron microscopy there was intensive remodeling of peripheral glomerular basement membranes with presence of intramembranous, subepithelial and subendothelial deposits (black arrow). There were also mesangial deposits (white arrow). Further, there was extensive loss of foot processes (red arrow) (electron microscopy, x2800).
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case_images: PMC11309753_01_cnd-2024-0014-0001-540013_F03.jpg
case_images: F3
case_images: A detailed description of the histologic findings is given in Table 1 and illustrated in Figure 3a-d.