Banff scoring of kidney allograft biopsies: "Manual" application vs software-assisted sign-out.

OBJECTIVES: Pathologists interpreting kidney allograft biopsies using the Banff system usually start by recording component scores (eg, i, t, cg) using histopathologic criteria committed to memory. Component scores are then melded into diagnoses using the same manual/mental processes. This approach to complex Banff rules during routine sign-out produces a lack of fidelity and needs improvement. METHODS: We constructed a web-based "smart template" (software-assisted sign-out) system that uniquely starts with upstream Banff-defined additional diagnostic parameters (eg, infection) and histopathologic criteria (eg, percent interstitial inflammation) collectively referred to as feeder data that is then translated into component scores and integrated into final diagnoses using software-encoded decision trees. RESULTS: Software-assisted sign-out enables pathologists to (1) accurately and uniformly apply Banff rules, thereby eliminating human inconsistencies (present in 25% of the cohort); (2) document areas of improvement; (3) show improved correlation with function; (4) examine t-Distributed Stochastic Neighbor Embedding clustering for diagnosis stratification; and (5) ready upstream incorporation of artificial intelligence-assisted scoring of biopsies. CONCLUSIONS: Compared with the legacy approach, software-assisted sign-out improves Banff accuracy and fidelity, more closely correlates with kidney function, is practical for routine clinical work and translational research studies, facilitates downstream integration with nonpathology data, and readies biopsy scoring for artificial intelligence algorithms.

Tissue-resident memory T cell maintenance during antigen persistence requires both cognate antigen and interleukin-15.

Our understanding of tissue-resident memory T (TRM) cell biology has been largely developed from acute infection models in which antigen is cleared and sterilizing immunity is achieved. Less is known about TRM cells in the context of chronic antigen persistence and inflammation. We investigated factors that underlie TRM maintenance in a kidney transplantation model in which TRM cells drive rejection. In contrast to acute infection, we found that TRM cells declined markedly in the absence of cognate antigen, antigen presentation, or antigen sensing by the T cells. Depletion of graft-infiltrating dendritic cells or interruption of antigen presentation after TRM cells were established was sufficient to disrupt TRM maintenance and reduce allograft pathology. Likewise, removal of IL-15 transpresentation or of the IL-15 receptor on T cells during TRM maintenance led to a decline in TRM cells, and IL-15 receptor blockade prevented chronic rejection. Therefore, antigen and IL-15 presented by dendritic cells play nonredundant key roles in CD8 TRM cell maintenance in settings of antigen persistence and inflammation. These findings provide insights that could lead to improved treatment of chronic transplant rejection and autoimmunity.

New onset MDA-5 positive dermatomyositis and massive perivillous fibrin deposition in third trimester of pregnancy: A case report.

We report a case of a 42-year-old woman (Gravida 1, Para 1) who presented in her third trimester of pregnancy with a photo distributed eruption and arthralgias and was subsequently diagnosed with dermatomyositis. She had an emergency Caesarean section at 34 weeks plus 6 days gestation due to decreased fetal movements and non-reassuring fetal heart rate. Her placenta was sent for histopathology and showed features of massive perivillous fibrin deposition. To our knowledge, this is the first case of MDA-5 positive dermatomyositis in pregnancy with a live delivery.

Standardizing the histological assessment of late posttransplantation biopsies from pediatric liver allograft recipients.

Excellent short-term survival after pediatric liver transplantation (LT) has shifted attention toward the optimization of long-term outcomes. Despite considerable progress in imaging and other noninvasive modalities, liver biopsies continue to be required to monitor allograft health and to titrate immunosuppression. However, a standardized approach to the detailed assessment of long-term graft histology is currently lacking. The aim of this study was to formulate a list of histopathological features relevant for the assessment of long-surviving liver allograft health and to develop an approach for assessing the presence and severity of these features in a standardized manner. Whole-slide digital images from 31 biopsies obtained ≥4 years after transplantation to determine eligibility for an immunosuppression withdrawal trial were selected to illustrate a range of typical histopathological findings seen in children with clinically stable grafts, including those associated with alloantibodies. Fifty histological features were independently assessed and, where appropriate, scored semiquantitatively by six pathologists to determine inter- and intraobserver reproducibility of the histopathological features using unweighted and weighted kappa statistics; the latter metric enabled distinction between minor and major disagreements in parameter severity scoring. Weighted interobserver kappa statistics showed a high level of agreement for various parameters of inflammation, interface activity, fibrosis, and microvascular injury. Intraobserver agreement for these features was even more substantial. The results of this study will help to standardize the assessment of biopsies from long-surviving liver allografts, aid the recognition of important histological features, and facilitate international comparisons and clinical trials aiming to improve outcomes for children undergoing LT.

Late graft dysfunction after pediatric heart transplantation is associated with fibrosis and microvasculopathy by automated, digital whole-slide analysis.

BACKGROUND: Histopathologic features of late graft dysfunction (LGD) in endomyocardial biopsies (EMBs) after pediatric heart transplantation (HT) have been incompletely described and rarely quantified. We employed automated, morphometric analysis of whole-slide EMB images to objectively quantify fibrosis and microvasculopathy after pediatric HT. METHODS: Nine recipients with clinical LGD were matched with controls on age, listing diagnosis, crossmatch and time since HT. Fibrosis was quantified as percent tissue area with fibrosis and capillary density as capillaries per unit area, number of capillary "neighbors" within 30 µm of each myocyte and myocyte-to-nearest-capillary diffusion distance. Clinical data, including all EMB reports, were also reviewed. RESULTS: The groups were well matched for age at HT (median 4.0 vs 3.1 years), listing diagnosis (50% congenital heart disease for each), positive crossmatch (11% each) and days post-HT (2,628 vs 2,894, p = 0.69). Despite a similar number of previous EMBs (median 23 each, p = 0.43), areas occupied by fibrosis were greater in LGD cases (44.5% vs 23.2%, p = 0.012). Capillary number/area data were not statistically different between LGD cases and controls (378/mm2 vs 559/mm2, p = 0.57), but LGD cases more commonly had zero capillary neighbors (35% vs 20%, p = 0.02) and greater myocyte-to-nearest-capillary distances (27.1 µm vs 18.7 µm, p = 0.005). Cumulative rejection history correlated with fibrosis (r = 0.49, p = 0.039) and myocyte-to-nearest-capillary distance (r = 0.5, p = 0.036). CONCLUSIONS: LGD after pediatric HT is associated with previous rejection and characterized histologically by fibrosis and microvasculopathy, which are not readily appreciated by traditional semi-quantitative EMB analysis. Software-assisted EMB analysis may enable greater pathophysiologic understanding of LGD and identification of targets for future study and intervention.

Prospective population-based cohort of inflammatory bowel disease in the biologics era: Disease course and predictors of severity.

BACKGROUND AND AIM: We have previously found high incidence of inflammatory bowel disease (IBD) in Australia. A population-based registry was established to assess disease severity, frequency of complications, and prognostic factors. METHODS: Incident cases were prospectively identified over 4 years. Early disease severity was assessed according to need for hospitalization and resective surgery and medication use. RESULTS: We report on the early outcomes (median 18 months, range 12-60 months) for 252 patients comprising 146 with Crohn's disease (CD), 96 with ulcerative colitis (UC), and 10 IBD undifferentiated. Eighty-seven percent of CD patients had inflammatory disease at diagnosis, and this reduced to 73% at 5 years (n = 38). Immunomodulators were prescribed in 57% of CD patients and 19% with UC. A third of all CD patients were hospitalized, the majority (77%) in the first 12 months. Risk factors for hospitalization included penetrating, perianal, and ileocolonic disease (P < 0.05). Twenty-four percent of UC patients were hospitalized, most within the first 12 months. Intestinal resection rates were 13% at 1 year in CD and 26% at 5 years. Risk factors include penetrating and stricturing disease (P < 0.001) and ileal involvement (P < 0.05). Colectomy rates in UC were 2% and 13% at 1 and 5 years. High C-reactive protein (CRP) at diagnosis was associated with colectomy. CONCLUSIONS: A high rate of inflammatory disease, frequent immunomodulator use in CD, and a low rate of surgery in both CD and UC were identified. In CD, ileal involvement and complex disease behavior are associated with a more severe disease course, while in UC a high CRP predicted this outcome.