Neutrophilic Tubulitis as a Marker for Urinary Tract Infection in Renal Allograft Biopsies With C4d Deposition

Abstract

Neutrophilic tubulitis accompanied by neutrophil clusters in the tubular lumen is a useful marker of UTI, even in the presence of PTC C4d deposition. Therapeutic response to antibiotics is limited by co-existent T-cell or antibody-mediated rejection and underlying chronic allograft nephropathy.

Acute Pyelonephritis in Renal Allografts–A New Role for MicroRNAs?

“…We identified biopsies from 64 renal allograft recipients, transplanted between 2003 and 2011, in whom the allograft biopsy showed morphologic features of APN—interstitial in flammation with predominance of neutrophils, tubular infiltration with neutrophils, and formation of tubular microabscesses (24, 25) (see Figure S1A, S1B, SDC, http://links.lww.com/TP/A928). Of the 64 recipients, 49 had the biopsy within the first 2 years posttransplant.…”

“…Limited accuracy due to sampling error, patchy distribution of inflammation in pyelonephritis, and interobserver variability among pathologists are contributing factors. There are two recent studies highlighting difficulty in the biopsy diagnosis of APN in renal allografts: Gupta et al (25) and Mohamed et al (32). We found that in 24% (12/49) of the patients, biopsy showed overlapping biopsy features of APN and AR.…”

“…The digital multiplexed NanoString nCounter human microRNA expression assay (NanoString Technologies) was performed with 100 ng total RNA as input material (24, 25). …”

“…For normalization purposes, we adopted two methods—geometric mean of the top 100 most highly expressed miRNAs, and global sum method of stably expressed miRNA. The data were expressed in terms of absolute number of miRNAs in each sample (24, 25). …”

Gram-negative sepsis following biopsy of a transplant recipient with asymptomatic allograft pyelonephritis

“…Interstitial inflammation with a predominance of polymorphonuclear leukocytes (PMNs) and intra-tubular PMNs forming microabscesses are the hallmark histological features of AGPN. However, infiltration of PMNs can occur in ACR and, given the patchy nature of AGPN in addition to sampling issues, intra-tubular PMNs, and micro-abscesses may not always be seen on the biopsy sample, therefore, differentiating between AGPN and ACR can often be difficult [4,5]. Reports of the effect of AGPN on long-term graft and patient survival are conflicting with some showing a deleterious effect and others no difference.…”