Marijke van Dijk

Proposal for updating the pseudoxanthoma elasticum classification system and a review of the clinical findings

Pseudoxanthoma elasticum (PXE) is a systemic disorder affecting elastic tissues most markedly in skin, retina, and blood vessels. It is caused by mutations in the ABCC6 gene and is transmitted in an autosomal recessive fashion. In 1994 a new classification system for PXE was published as the result of a consensus conference. Since then the ABCC6 gene has been discovered. We propose that there is a need for a classification system incorporating all relevant systemic symptoms and signs, based on standardized clinical, histological, and molecular biological examination techniques. We re‐evaluated the histopathologic PXE signs and propose a classification system with unambiguous criteria leading to a consistent diagnosis of definitive, probable, or possible PXE world‐wide. We put this proposed classification forward to encourage further debate on the diagnosis of this multi‐organ disorder.

Whole slide images for primary diagnostics in dermatopathology: a feasibility study

Background During the last decade, whole slide images (WSI) have been used in many areas of pathology such as teaching, research, digital archiving, teleconsultation and quality assurance testing. However, WSI have not regularly been used for routine diagnosis, because of the lack of validation studies. Aim To test the validity of using WSI for primary diagnosis of skin diseases. Materials and methods 100 skin biopsies and resections which had been diagnosed light microscopically one year previously were scanned at 20× magnification, and rediagnosed by six pathologists (every pathologist assessed his own cases), having the original clinical information available, but blinded to the original diagnoses. The WSI diagnoses were compared to the initial light microscopy diagnosis and classified as concordant, slightly discordant (without clinical consequences) or discordant. Results The light microscopy and the WSI based diagnosis were concordant in 94% of the cases. The light microscopy and WSI diagnosis were slightly discordant in 6% of the cases. For one of the slightly discrepant cases the WSI diagnosis was considered better, while the original diagnosis was preferred for the other five cases. There were no discordant cases with clinical or prognostic implications. Conclusion Primary histopathological diagnosis of skin biopsies and resections can be done digitally using WSI.

The immunological phenotype of rituximab-sensitive chronic graft-versus-host disease: a phase II study

Chronic graft-versus-host disease is the major long-term complication after allogeneic stem cell transplantation with a suboptimal response rate to current treatments. Therefore, clinical efficacy and changes in lymphocyte subsets before and after rituximab treatment were evaluated in a prospective phase II study in patients with steroid-refractory chronic graft-versus-host disease. Overall response rate was 61%. Only responding patients were found to have increased B-cell numbers prior to treatment. B cells had a naïve-antigen-presenting phenotype and were mainly CD5 negative or had a low CD5 expression. Normal B-cell homeostasis was reestablished in responding patients one year after ritxumab treatment and associated with a significant decline in skin-infiltrating CD8+ T cells, suggesting that host B cells play a role in maintaining pathological CD8+ T-cell responses. Imbalances in B-cell homeostasis could be used to identify patients a priori with a higher chance of response to rituximab treatment (Eudra-CT 2008-004125-42).

Pseudoxanthoma elasticum: Wide phenotypic variation in homozygotes and no signs in heterozygotes for the c.3775delT mutation in ABCC6

Purpose: Pseudoxanthoma elasticum is an autosomal recessive disorder of elastic tissue in the skin, eyes, and cardiovascular system, caused by mutations in the ABCC6 gene. The purpose of this study was to check variability in expression within one genotype and look for pseudoxanthoma elasticum signs in heterozygotes.Methods: We examined a relatively large, in comparison with the present literature, group of adult persons homozygous or heterozygous for the c.3775delT mutation in the ABCC6 gene, from a genetically isolated population in the Netherlands. All participants filled out a questionnaire and underwent standardized dermatologic and ophthalmologic examinations with photography of skin and fundus abnormalities. Skin biopsies from affected skin or a predilection site and/or a scar were examined and compared with biopsies from controls.Results: Skin abnormalities, ophthalmologic signs, and cardiovascular problems varied greatly among the 15 homozygous participants. There was no correlation among severity of skin, eyes, or cardiovascular abnormalities. None of the 44 heterozygous participants had any sign of pseudoxanthoma elasticum on dermatologic, histopathologic, and/or ophthalmologic examination, but 32% had cardiovascular disease.Conclusion: Individuals homozygous for the c.3775delT mutation can have a highly variable phenotype. We did not find pseudoxanthoma elasticum eye or skin abnormalities in the heterozygous family members.

The EPA-based Utrecht undergraduate clinical curriculum: Development and implementation

Abstract Aim: As reports of the application of entrustable professional activities (EPAs) increase, not only for postgraduate but also for undergraduate medical education, there is a need for descriptions of what a UME curriculum with EPAs could look like. We provide such a description based on the experiences at University Medical Center Utrecht, the Netherlands, which can be used as an example by other curriculum developers. Methods: In a three-year process, the UMC Utrecht Curriculum Committee developed a clinical workplace curriculum with an EPA structure, taking into account examples, such as the US Core EPAs for Entering Residency, and recommendations to integrate and increase the length of clerkships. Results: In the resulting curriculum, operational from 2016, students train to be trusted with indirect supervision before graduation in five broad EPAs: the clinical consultation; general medical procedures; informing, advising and guiding patients and families; communicating and collaborating with colleagues; and extraordinary patient care. Each of these integrates smaller (nested) EPAs that receive focused training attention in integrated clerkships at various moments and must be signed off for entrustment with indirect supervision to complete the clerkship. Discussion: The framework of EPAs went through many iterations before it was consolidated. Among the issues that required special attention was the application of a supervision levels scale for sign-off, the necessity to cover all relevant clinical content while not labeling too many small tasks each as a separate EPA, methods of EPA-focused assessment in the workplace and the creation of an e-portfolio model to serve assessment and entrustment.

Histological Assessment of the Sclerotic Graft-versus-Host Response in the Humanized RAG2−/−γc−/− Mouse Model

Graft-versus-host disease (GVHD) remains a frequently occurring and difficult-to-treat complication in human allogeneic stem cell transplantation. Murine transplantation models are often used to study and understand the complex pathogenesis of GVHD and to explore new treatment strategies. Although GVHD kinetics may differ in murine and human models, adequate models are essential for identification of the crucial factors responsible for the major pathology in GVHD. We present a detailed description of the specific histological features of a graft-versus-host-induced fibrotic response in xenogeneic RAG2(-/-)γc(-/-) mice after total body irradiation and injection with human peripheral blood mononuclear cells. We describe the full morphological features of this reaction, including a detailed analysis of the specific tissue infiltration patterns of the human peripheral blood mononuclear cells. Our data show the development of fibrosis, predominantly near blood vessels, and reveal different cell populations and specific cell migration patterns in the affected organs. The combination of immunohistochemical cell characterization and mRNA expression analysis of both human (donor)- and murine (host)-derived cytokines reveals an interaction between host tissues and donor-derived cells in an entangled cytokine profile, in which both donor- and host-derived cytokines contribute to the formation of fibrosis.

No non-sentinel node involvement in melanoma patients with limited Breslow thickness and low sentinel node tumour load.

Bogenrieder T, van Dijk M R, Blokx W A M, Ramrath K, Seldenrijk K, Stolz W & van Diest P J
(2011) Histopathology59, 318–326

Infiltration of Plasma Cells in the Iris of Children With ANA-Positive Anterior Uveitis

PURPOSE We investigated inflammatory cell infiltrates in iris biopsies in uveitis associated with juvenile idiopathic arthritis (JIA) in comparison with other pediatric uveitis entities and noninflammatory pediatric controls. METHODS Iridectomy specimens were obtained during elective trabeculectomy from 31 eyes of 25 patients: 12 eyes with JIA-associated uveitis, 13 eyes with other uveitis entities, and 6 eyes with open angle nonuveitic juvenile glaucoma. Histopathologic and immunohistochemical analyses were performed. A semiquantitative scoring system was used with a scale ranging from 0 to 4 depending on the number of stained cells. RESULTS An inflammatory infiltrate was present in 8/12 (67%) specimens with JIA-associated uveitis. The cellular infiltrate in JIA specimens was characterized by the presence of CD138+ plasma cells and CD68+ macrophages, while the presence of CD20+, CD4+, and CD8+ cells was variable. Presence of plasma cells in the inflammatory infiltrates in anterior uveitis correlated with antinuclear autoantibody (ANA) positivity regardless of the diagnosis of JIA. CD4+ and CD8+ T cells were not always detectable in the iris biopsies of all childhood uveitis patients, although a slight predominance of CD4+ cells was noted. CONCLUSIONS Children with ANA-positive anterior uveitis often show an infiltrate of plasma cells, regardless of the diagnosis of JIA. The iris of JIA-associated uveitis patients is additionally characterized by the presence of various numbers of macrophages.

Risk of Non-melanoma Skin Cancer in Patients with Atopic Dermatitis Treated with Oral Immunosuppressive Drugs

There is uncertainty about the risk of developing non-melanoma skin cancer (NMSC), including basal cell carcinoma and squamous cell carcinoma (SCC), in patients with atopic dermatitis (AD) treated with oral immunosuppressive drugs. A total of 557 patients with AD treated with these drugs in the University Medical Center Utrecht and Groningen, the Netherlands, were analysed. NMSC after oral immunosuppressive treatment was reported in 18 patients (3.2%). The standardized incidence ratio for developing SCC was 13.1 (95% confidence interval (95% CI) 6.5-19.7). Patients developing NMSC were older at the start of therapy (p<0.001) and data lock (p<0.001) compared with patients without NMSC. No significant differences were found in sex, cumulative days of oral immunosuppressive drugs and follow-up between these groups (p=0.42, p=0.88, and p=0.34, respectively). In interpreting these results it is important to include other factors, such as lack of association between treatment duration and tumour development and the long interval between treatment discontinuation and tumour development in some patients.

The number of T cell allo-epitopes associates with CD4+ and CD8+ T-cell infiltration in pediatric cutaneous GVHD.

Risk factors for graft-versus-host disease (GVHD) following allogeneic hematopoietic stem-cell transplantation (HCST) include: HLA mismatches, sex-mismatch, and stem-cell source. We retrospectively analyzed if HLA- and sex-mismatching quantitatively affects the composition of GVHD-induced T-cell infiltrates. We quantified absolute numbers of CD4+ and CD8+ T cells present in tissue sections from skin biopsies of 23 pediatric HSCT-recipients with GVHD. HSCT with a sex-mismatched unrelated donor was associated with an increased number of CD4+ T cells when compared to a sex-matched unrelated donor (p=0.01). The absolute numbers of skin-infiltrating T cells were increased in patients expressing T-cell epitopes derived from the recipients mismatched HLA, so called predicted indirectly recognizable HLA epitopes (PIRCHE). The combined expression of PIRCHE with a sex-mismatch resulted in the highest number of skin-infiltrating T cells. Our results indicate that an increased number of recipient-specific T-cell epitopes is associated with accumulation of CD4+ and CD8+ T cells in the skin.