Interstitial Nephritis: Wherefrom, Wherein, and Whereto.

Abnormalities of the renal interstitium were noted early while identifying chronic kidney disease in 1827; however, interest in glomerular and vascular lesions was then distracted from their further study. As a complication of scarlet fever, interstitial lesions attracted attention in 1859 and came to be defined as acute interstitial nephritis in 1898. The chronic form of interstitial nephritis was traditionally attributed to pyelonephritis until the advent of kidney biopsy in the 1950s, when interstitial lesions were recognized as an independent primary cause of chronic kidney disease from studies of analgesic nephropathy and vesico-ureteral reflux. The term tubulointerstitial nephritis was introduced in 1963 and promoted to denote the role of the tubules in the pathogenesis and the clinical presentation of interstitial nephritis as tubular dysfunction. Studies since then have established that fibrotic tubulointerstitial nephritis lesions correlate best with the severity and progression of kidney diseases independent of their etiology.