Most monogenic disorders have a primary clinical presentation. Inherited ISG15 deficiency, however, has manifested with two distinct presentations to date: susceptibility to mycobacterial disease and intracranial calcifications from hypomorphic interferon-II (IFN-II) production and excessive IFN-I response, respectively. Accordingly, these patients were managed for their infectious and neurologic complications. Herein, we describe five new patients with six novel ISG15 mutations presenting with skin lesions who were managed for dermatologic disease. Cellularly, we denote striking specificity to the IFN-I response, which was previously assumed to be universal. In peripheral blood, myeloid cells display the most robust IFN-I signatures. In the affected skin, IFN-I signaling is observed in the keratinocytes of the epidermis, endothelia, and the monocytes and macrophages of the dermis. These findings define the specific cells causing circulating and dermatologic inflammation and expand the clinical spectrum of ISG15 deficiency to dermatologic presentations as a third phenotype co-dominant to the infectious and neurologic manifestations.

(1) Background: Post-transplant lymphoproliferative disease (PTLD) is a significant complication of solid organ transplantation (SOT). However, there is lack of consensus in PTLD management. Our aim was to establish a present benchmark for comparison between international centers and between various organ transplant systems and modalities; (2) Methods: A cross-sectional questionnaire of relevant PTLD practices in pediatric transplantation was sent to multidisciplinary teams from 17 European center members of ERN TransplantChild to evaluate the centers’ approach strategies for diagnosis and treatment and how current practices impact a cross-sectional series of PTLD cases; (3) Results: A total of 34 SOT programs from 13 European centers participated. The decision to start preemptive treatment and its guidance was based on both EBV viremia monitoring plus additional laboratory methods and clinical assessment (61%). Among treatment modalities the most common initial practice at diagnosis was to reduce the immunosuppression (61%). A total of 126 PTLD cases were reported during the period 2012–2016. According to their histopathological classification, monomorphic lesions were the most frequent (46%). Graft rejection after PTLD remission was 33%. Of the total cases diagnosed with PTLD, 88% survived; (4) Conclusions: There is still no consensus on prevention and treatment of PTLD, which implies the need to generate evidence. This might successively allow the development of clinical guidelines.

Background: There is considerable variation in vaccination practices between pediatric transplant centers. This study aims to evaluate active immunization attitudes and practices among ERN‐TransplantChild centers and identify potential areas of improvement that could be addressed by shared evidence‐based protocols.Methods: A cross‐sectional questionnaire of attitudes and practices toward immunization of pediatric SOT and HSCT candidates and recipients was sent to a representative member of multidisciplinary teams from 27 European centers belonging to the ERN‐TransplantChild.Results: A total of 28/62 SOT programs and 6/12 HSCT programs across 21 European centers participated. A quarter of centers did not have an on‐site protocol for the immunizations. At the time of transplantation, pediatric candidates were fully immunized (80%–100%) in 57% and 33% of the SOT and HSCT programs. Variations in the time between vaccine administration and admission to the waiting list were reported between the centers, with 2 weeks for inactivated vaccines and variable time (2–4 weeks) for live‐attenuated vaccines (LAVs). Almost all sites recommended immunization in the post‐transplant period, with a time window of 4–8 months for the inactivated vaccines and 16–24 months for MMR and Varicella vaccines. Only five sites administer LAVs after transplantation, with seroconversion evaluated in 80% of cases.Conclusions: The immunization coverage of European pediatric transplant recipients is still inconsistent and far from adequate. This survey is a starting point for developing shared evidence‐based immunization protocols for safe vaccination among pediatric transplant centers and generating new research studies.