The Pathophysiology and Impact of Inflammation in Nonscarred Renal Interstitium: The Banff i Lesion.

BACKGROUND: Interstitial inflammation (i-INT) is the driver of T-cell-mediated rejection. Its causes, pathophysiology, kinetics, and outcomes are poorly documented. METHODS: The role of i-INT was evaluated in 2055 biopsies from 775 renal transplant recipients. RESULTS: i-INT was present in 374 (18.2% prevalence) from acute and subclinical rejection (67.4%); interstitial fibrosis and tubular atrophy (14.4%); BK virus nephropathy (BKVAN) 9.9%; and acute tubular necrosis (ATN with i-INT) in 5.9% of cases. i-INT was predicted by prior T-cell-mediated rejection and BKVAN, human leukocyte antigen mismatch, cyclosporine therapy, and indication biopsy for dysfunction. It correlated with tubulitis, arteritis, and antibody markers within concurrent histology (P < 0.001). After treatment, renal functional recovery was best with histological ATN, milder i-INT, and early posttransplant biopsy times. The initial histological improvement of inflammation depended on baseline i-INT severity. Complete resolution to Banff i0 was predicted by early biopsy time, antilymphocyte therapy, recipient age, and medication compliance (all P < 0.001). Clearance i-INT was followed by delayed resolution of tubulitis (P < 0.001). i-INT was associated with histological ATN, renal dysfunction, and increased incident fibrosis on sequential pathology. Progressive fibrosis following related-rejection i-INT was dependent on tubulitis using multivariable analysis. In contrast, fibrogenesis after BKVAN or ATN was unrelated to inflammation. i-INT cases were followed by recurrent rejection in 35.3%, increased graft loss, and greater patient mortality. Multiple complementary outcome analyses determined the optimal lower diagnostic threshold for inflammation was Banff i1 score. CONCLUSIONS: i-INT is a heterogeneous pathological phenotype that results in adverse functional and structural outcomes, for which active and robust therapy should be considered.

Clinical Utility of Urinary Cytology to Detect BK Viral Nephropathy.

BACKGROUND: Reactivation of BK polyoma virus can result in destructive viral allograft nephropathy (BKVAN) with limited treatment options. Screening programs using surrogate markers of viral replication are important preventive strategies, guiding immunosuppression reduction. METHODS: We prospectively evaluated the diagnostic test performance of urinary decoy cells and urinary SV40T immunochemistry of exfoliated cells, to screen for BKVAN, (defined by reference histology with SV40 immunohistochemistry, n = 704 samples), compared with quantitative viremia, from 211 kidney and 141 kidney-pancreas transplant recipients. RESULTS: The disease prevalence of BKVAN was 2.6%. Decoy cells occurred in 95 of 704 (13.5%) samples, with a sensitivity of 66.7%, specificity of 88.6%, positive predictive value (PPV) of 11.7%, and negative predictive value of 98.5% to predict histologically proven BKVAN. Quantification of decoy cells improved the PPV to 32.1% (10 ≥ cells threshold). Immunohistochemical staining of urinary exfoliated cells for SV40T improved sensitivity to 85.7%, detecting atypical or degenerate infected cells (specificity of 92.3% and PPV of 33.3%), but was hampered by technical failures. Viremia occurred in 90 of 704 (12.8%) with sensitivity of 96.3%, specificity of 90.3%, PPV of 31.5%, and negative predictive value of 99.8%. The receiver-operator curve performance of quantitative viremia surpassed decoy cells (area under the curve of 0.95 and 0.79, respectively, P = 0.0018 for differences). Combining decoy cell and BK viremia in a diagnostic matrix improved prediction of BKVAN and diagnostic risk stratification, especially for high-level positive results. CONCLUSIONS: Although quantified decoy cells are acceptable surrogate markers of BK viral replication with unexceptional test performances, quantitative viremia displayed superior test characteristics and is suggested as the screening test of choice.

Selective BRAF inhibitors induce marked T-cell infiltration into human metastatic melanoma.

PURPOSE: To evaluate the effects of treatment with the potent mutant BRAF inhibitors GSK2118436 or vemurafenib (PLX4720) on immune responses to metastatic melanoma in tissues taken before and after treatment. EXPERIMENTAL DESIGN: Thirty-seven tumor biopsies were collected from 15 patients with unresectable American Joint Committee on Cancer stage III or IV melanoma immediately before and approximately 7 days after the commencement of BRAF inhibitor treatment and at the time of tumor progression. Immunohistochemical staining was carried out on the biopsies using specific antibodies for CD8, CD4, CD20, CD1a, and Granzyme B. RESULTS: Tumor infiltration by CD4(+) and CD8(+) lymphocytes increased markedly following BRAF inhibitor treatment (both ρ = 0.015). There was a correlation between the degree of tumor infiltration by CD8(+) and Granzyme B-expressing lymphocytes in post-BRAF inhibitor-treated biopsies (r = 0.690 and ρ = 0.013). Increased intratumoral CD8(+) lymphocyte expression was correlated with a reduction in tumor size and an increase in necrosis in posttreatment biopsies (r = -0.793, ρ = 0.011; and r = 0.761, ρ = 0.004, respectively). CONCLUSIONS: The increase in tumor-infiltrating lymphocytes induced by treatment with BRAF inhibitors provides strong support for conducting trials that combine BRAF inhibitors with immunotherapy in the hope of prolonging clinical responses.

Sentinel lymph node biopsy in histologically ambiguous melanocytic tumors with spitzoid features (so-called atypical spitzoid tumors).

BACKGROUND: The distinction of Spitz nevi from melanomas with spitzoid morphology can be difficult. For lesions with overlapping histopathologic features, it may be impossible to predict their malignant potential with certainty. The current study evaluated the role of sentinel lymph node (SLN) biopsy in patients with such atypical spitzoid tumors. METHODS: The clinical and histopathologic features of 21 patients with atypical spitzoid tumors who underwent SLN biopsy were reviewed and correlated with the presence or absence of metastatic tumor in their corresponding SLNs. RESULTS: The atypical histopathologic features that were most frequently present included incomplete maturation (11 patients, 52%), two or more dermal mitoses per square millimeter (13 patients, 62%), and deep dermal mitoses (11 patients, 52%). Six patients (29%) showed SLN metastasis. There were histopathologic differences between tumors with positive SLN when compared with tumors with negative SLN: mean tumor thickness (3.38 mm vs. 2.04 mm), incomplete maturation (83% vs. 40%), median dermal mitotic rate (3.5/mm(2) vs. 2/mm(2)), deep dermal mitoses (83% vs. 47%), and expansile dermal nodules (50% vs. 13%). However, of these, only the difference in mean tumor thickness reached statistical significance (P < .05). CONCLUSIONS: SLN biopsy offers a means of assessing the metastatic potential of atypical spitzoid tumors and aids in the management of these patients by selecting patients who may benefit from a regional node field dissection and those in whom the use of adjuvant therapies could be considered.

Long-term protective effect of mature DC-LAMP+ dendritic cell accumulation in sentinel lymph nodes containing micrometastatic melanoma.

PURPOSE: In a previous immunohistochemical study of dendritic cells (DC) in sentinel lymph nodes (SLN) draining regressing melanomas, we found that the accumulation of mature DC-LAMP(+) DCs in SLNs was associated with local expansion of antigen-specific memory effector CTLs and the absence of metastasis in downstream lymph nodes. The aim of this study was to investigate the prognostic importance of the maximal density of mature DCs in SLNs. EXPERIMENTAL DESIGN: A total of 458 consecutive patients with micrometastatic melanoma within SLNs were eligible for analysis. The maximal density of mature DC-LAMP(+) DCs was evaluated by three independent observers and categorized into three classes (<100, 100 to <200, and >or=200/mm(2)). RESULTS: There was excellent interobserver reproducibility for maximum density of mature DC-LAMP(+) DC scores (kappa score = 0.82). There were differences in the maximal density scores and staining intensity according to the treating melanoma center (P < 0.001). The higher the mature DC density in the SLN is, the longer is the duration of survival [P = 0.047; hazard ratio, 0.70; 95% confidence interval, 0.50-1.00]. Adjusted by thickness and ulceration, the prognostic importance of DC density was lower (P = 0.36). CONCLUSION: This study is the first to report the prognostic value of DC-LAMP(+) DC counts in SLNs containing metastatic melanoma. Patients with a high density of mature DCs (>or=200/mm(2)) have the lowest risk of death. It also provides evidence that a lack of maturation in the SLNs is important in biological facilitation of melanoma progression.