Background & Aims Patients with inflammatory bowel disease (IBD) who have been exposed to thiopurines might have an increased risk of skin cancer. We assessed this risk among patients in France. Methods We performed a prospective observational cohort study of 19,486 patients with IBD, enrolled from May 2004 to June 2005, who were followed up until December 31, 2007. The incidence of nonmelanoma skin cancer (NMSC) in the general population, used for reference, was determined from the French Network of Cancer Registries. Results Before the age of 50 years, the crude incidence rates of NMSC among patients currently receiving or who previously received thiopurines were 0.66/1000 and 0.38/1000 patient-years, respectively; these values were 2.59/1000 and 1.96/1000 patient-years for the age group of 50 to 65 years and 4.04/1000 and 5.70/1000 patient-years for patients older than 65 years. Among patients who had never received thiopurines, the incidence of NMSC was zero before the age of 50 years, 0.60/1000 for the ages of 50 to 65 years, and 0.84/1000 for those older than 65 years. A multivariate Cox regression model stratified by propensity score quintiles showed that ongoing thiopurine treatment (hazard ratio [HR], 5.9; 95% confidence interval [CI], 2.1–16.4; P = .0006) and past thiopurine exposure (HR, 3.9; 95% CI, 1.3–12.1; P = .02) were risk factors for NMSC. They also identified age per 1-year increase as a risk factor for NMSC (HR, 1.08; 95% CI, 1.05–1.11; P < .0001). Conclusions Ongoing and past exposure to thiopurines significantly increases the risk of NMSC in patients with IBD, even before the age of 50 years. These patients should be protected against UV radiation and receive lifelong dermatologic screening.

Endothelial progenitor cell (EPC) nomenclature remains ambiguous and there is a general lack of concordance in the stem cell field with many distinct cell subtypes continually grouped under the term “EPC.” It would be highly advantageous to agree on standards to confirm an endothelial progenitor phenotype and this should include detailed immunophenotyping, potency assays, and clear separation from hematopoietic angiogenic cells which are not endothelial progenitors. In this review, we seek to discourage the indiscriminate use of “EPCs,” and instead propose precise terminology based on defining cellular phenotype and function. Endothelial colony forming cells and myeloid angiogenic cells are examples of two distinct and well‐defined cell types that have been considered EPCs because they both promote vascular repair, albeit by completely different mechanisms of action. It is acknowledged that scientific nomenclature should be a dynamic process driven by technological and conceptual advances; ergo the ongoing “EPC” nomenclature ought not to be permanent and should become more precise in the light of strong scientific evidence. This is especially important as these cells become recognized for their role in vascular repair in health and disease and, in some cases, progress toward use in cell therapy. Stem Cells Translational Medicine 2017;6:1316–1320

Fetal cells enter the maternal circulation during all pregnancies.^1,2 They can persist in maternal blood or tissues for decades, creating a state of physiologic microchimerism in the parous woman.³ Recent studies detected male cells of presumed fetal origin in 30% to 50% of healthy women who had prior male pregnancies.⁴ The long-term consequences of fetal cell microchimerism for maternal health are only beginning to be appreciated. Fetal microchimeric cells are present in higher numbers in women with some autoimmune diseases, such as systemic sclerosis, than in control groups.^5,6 We have also observed fetal cells in the tissues of women with nonautoimmune disorders, such as hepatitis C⁷ and cervical cancer.⁸ Thus, we developed an alternate hypothesis in which fetal cells were associated with the maternal response to injury as opposed to causing disease.

Erythema nodosum and pyoderma gangrenosum are the most common cutaneous manifestations in inflammatory bowel diseases (IBD). We conducted the current study to assess the cumulative prevalence of erythema nodosum and pyoderma gangrenosum in patients with IBD and to appraise their association with demographic, clinical, and prognostic factors related to IBD. Between 2000 and 2005, data for all patients with IBD at our gastroenterology department were prospectively and systematically collected using a standardized protocol. Among 2402 patients (1521 diagnosed with Crohn disease [63.3%] and 744 with ulcerative colitis [31.0%]), 140 (5.8%) had atleast 1 skin manifestation. The most frequent dermatologic symptoms were erythema nodosum (4.0%) and pyoderma gangrenosum (0.75%). In multivariate analyses, erythema nodosum was significantly and independently associated with a diagnosis of Crohn disease (p < 0.001), female sex (p < 0.001), eye and joint involvement (p < 0.001), and pyoderma gangrenosum (p < 0.0001). Among patients with Crohn disease, erythema nodosum was associated with isolated colonic involvement (p = 0.0001). Pyoderma gangrenosum was significantly and independently associated with black African origin (p = 0.003), familial history of ulcerative colitis (p = 0.0005), uninterrupted pancolitis as the initial location of IBD (p = 0.03), permanent stoma (p = 0.002), eye involvement (p = 0.001), and erythema nodosum (p < 0.0001). It is noteworthy that the association between pyoderma gangrenosum and permanent stoma persisted after exclusion of patients with peristomal pyoderma gangrenosum (p = 0.07). In conclusion, neither erythema nodosum nor pyoderma gangrenosum was significantly associated with the severity criteria in IBD; however, their occurrence may reflect a peculiar phenotype among affected patients.

Fetal cells circulate in pregnant women and persist in blood and tissue for decades post-partum. The mother thus becomes chimeric. Factors that may influence such fetal cell microchimerism include histocompatibility, fetal or placental abnormalities, or a reproductive history that includes miscarriage or elective termination. Fetal cell microchimerism is associated with some maternal autoimmune diseases, such as systemic sclerosis. Moreover, a novel population of fetal cells, the pregnancy-associated progenitor cells (PAPCs), appears to differentiate in diseased or injured maternal tissue. The cellular origin of these cells is at present unknown but could be a hematopoietic stem cell, a mesenchymal stem cell, or a novel cell type. Pregnancy therefore results in the acquisition of cells with stem-cell-like properties that may influence maternal health post-partum. Rather than triggering disease, these cells may instead combat it.