Renal lesions of
IgG4-related disease have been reported recently. Most of them are
tubulointerstitial nephritis, and a definite
glomerulonephritis complicating
IgG4-related disease is very rare. We report here a case of definite
glomerulonephritis and concurrent
tubulointerstitial nephritis complicating
retroperitoneal fibrosis with a high serum level of
IgG4. A 68-year-old Japanese woman was referred to our hospital for investigation of
anasarca. We diagnosed
her disease as a
nephrotic syndrome and left hydroureteronephrosis due to
retroperitoneal fibrosis. Her laboratory data revealed a high serum level of
IgG4, renal injury,
hypoproteinemia, hypocomplementemia, a positive finding of circulating immunocomplex (CIC), and negative findings ofautologous
antibodies suggesting
systemic lupus erythematosus (SLE) or Sjögren's syndrome (SS). A diagnosis of SLE or SS could not be made clinically. Right renal biopsy revealed endocapillary proliferative
glomerulonephritis with crescent formation and concurrent
tubulointerstitial nephritis. Infiltration of plasma cells in interstitium was more conspicuous than seen with ordinary
tubulointerstitial nephritis, and in most of them
IgG4 was positive. We placed a percutaneous nephrostomy
catheter in her left kidney, and prescribed
prednisolone and
cyclosporine. The responses to
prednisolone and
cyclosporine therapies were very good. Further studies are needed to clarify the relationship between
glomerulonephritis and
IgG4-related disease. However, when considering renal lesions of
IgG4-related disease, we think that hypocomplementemia, a positive finding of CIC, negative findings of autologous
antibodies suggesting SLE or SS, conspicuous interstitial infiltration of IgG4-positive plasma cells, and a good response to
steroid or
immunosuppressant therapy are key points.