Tubulointerstitial nephritis with IgG4-positive plasma cell infiltration and tertiary lymphoid tissue in a patient with cryoglobulinemic vasculitis: a case report.

Tertiary lymphoid tissue (TLT) develops at sites of chronic immune stimulation, including infection, autoimmune disease, transplant rejection, and cancer. Recently, TLT has been focused on an indicator for poor renal prognosis in various kidney diseases. In cryoglobulinemic vasculitis (CV), specific glomerular and vascular lesions are seen; however, tubulointerstitial lesions are usually nonspecific. We herein report the case of a 74-year-old man with idiopathic CV with rare tubulointerstitial lesions, such as tubulointerstitial nephritis (TIN) with IgG4-positive plasma cell infiltration and TLT. To our knowledge, this is the first report identifying TLT in the kidney biopsy in a patient with CV. Glucocorticoid improved the renal outcome. The association between CV and TIN with TLT remains unknown.