A 38-year-old woman presents to the emergency department with progressive swelling around the eyes and in both feet. She reports being in her usual state of health until 1 week ago, when she first noticed that her shoes and rings were becoming tight. She is afebrile. Vital signs show heart rate of 75/min and blood pressure of 168/83 mm Hg. She is unsure of her baseline blood pressure. Physical examination is notable for periorbital swelling and 2+ pitting edema at the ankles. Urinalysis in the emergency department is positive for protein. She is admitted for further evaluation of kidney disease, and subsequent testing shows low serum C3 levels. Kidney biopsy (Figure A) demonstrates a “tram-track” appearance of the glomerular basement membrane. Which of the following, if present in this patient’s medical history, would most likely explain the etiology of her kidney disease?