Collapsing glomerulopathy associated with parvovirus B19 and systemic lupus erythematosus in a patient with APOL1 high-risk variant for nephropathy.

Collapsing glomerulopathy (CG) has a severe course typically associated with viral infections, especially HIV and parvovirus B19, systemic lupus erythematosus (SLE), among other etiologies. A 35-year-old woman with recent use of a JAK inhibitor due to rheumatoid arthritis presented with a 2-week history of fever, cervical adenopathy, and facial erythema. After admission, anemia, hypoalbuminemia, proteinuria, and severe acute kidney injury were noted. SLE was diagnosed and parvovirus B19 DNA was detected in serum samples. Kidney biopsy showed CG without any typical features of lupus nephritis. The patient was treated with prednisone and presented marked improvement of anemia and kidney function after a few weeks. In this case, the patient with SLE presented CG possibly caused by parvovirus B19 infection associated with homozygous apolipoprotein 1 (APOL1) G1 genotype, which has been described as a determinant risk factor for this glomerulopathy. It is not clear whether SLE had a causal relationship with glomerular disease or was a concurrent cause. Treatment can be challenging in such a context, as no antiviral drug is efficient and immunosuppression has no discernable benefit, although steroid use was efficient in treating renal manifestations in this case.