We performed 3 kidney biopsies in a 71-year-old man. At the first biopsy, we made the diagnosis of immunoglobulin G4 (IgG4)-related interstitial nephritis characterized by the simultaneous presence of IgG4-positive plasma cells and characteristic fibrosis with a bird's-eye pattern. At the second biopsy, rather than finding fibrosis as a post-inflammatory scar, we noted that steroid treatment had caused the simultaneous disappearance of IgG4-positive plasma cells and fibrosis and had restored the normal tubular structure. The third biopsy showed the recurrence of the disease with inflammatory cells accompanied by fibrosis. These findings suggest that IgG4-positive plasma cells and fibrosis occur simultaneously.
We experienced a 36-year-old man with lupus nephritis and antiphospholipid syndrome (APS) who received a donor kidney from his father. Twenty-two months after transplantation, at a time of poor adherence to immunosuppressants and warfarin, the patient developed sudden graft loss due to hemolytic uremic syndrome with rapid deterioration of renal function, thrombocytopenia, and hemolytic anemia. A kidney biopsy showed thrombotic microangiopathy (TMA) related to platelet thrombus formation; however, there was no recurrence of lupus and no findings suggestive of post-transplant rejection, so acute TMA associated with APS was thought to be the cause of the graft loss. This case highlights the importance of instructing patients with lupus nephritis to adhere to treatment with warfarin, a therapeutic drug for APS.