CXCL12+ dermal fibroblasts promote neutrophil recruitment and host defense by recognition of IL-17.

The skin provides an essential barrier for host defense through rapid action of multiple resident and recruited cell types, but the complex communication network governing these processes is incompletely understood. To define these cell-cell interactions more clearly, we performed an unbiased network analysis of mouse skin during invasive S. aureus infection and revealed a dominant role for CXCL12+ fibroblast subsets in neutrophil communication. These subsets predominantly reside in the reticular dermis, express adipocyte lineage markers, detect IL-17 and TNFα, and promote robust neutrophil recruitment through NFKBIZ-dependent release of CXCR2 ligands and CXCL12. Targeted deletion of Il17ra in mouse fibroblasts resulted in greatly reduced neutrophil recruitment and increased infection by S. aureus. Analogous human CXCL12+ fibroblast subsets abundantly express neutrophil chemotactic factors in psoriatic skin that are subsequently decreased upon therapeutic targeting of IL-17. These findings show that CXCL12+ dermal immune acting fibroblast subsets play a critical role in cutaneous neutrophil recruitment and host defense.

Mobile Subcutaneous Calcinosis Cutis: A Case Report of a Mobile Solitary Subepidermal Calcified Nodule on a Woman's Leg and a Review of Mobile Subcutaneous Tumors.

Calcinosis cutis describes the deposition of calcium in the dermis. A case of a 69-year-old woman with idiopathic calcinosis cutis that presented as a mobile subcutaneous nodule is described. The patient had an asymptomatic, firm, mobile subcutaneous nodule on her right lower leg of at least six months duration. The nodule could be easily moved from one location to another. An incisional biopsy was performed. Microscopic examination of the tissue specimen showed islands of basophilic calcium material in dense sclerotic dermal connective tissue establishing the diagnosis of calcinosis cutis. Mobile solitary calcification is an unusual presentation of idiopathic calcinosis cutis. In addition to idiopathic calcinosis cutis, benign mobile subcutaneous tumors have also been derived from adnexal structures of hair follicles and adipose tissue. Hence, not only idiopathic calcinosis cutis, but also subepidermal calcinosis in the ocular adnexa, proliferating trichilemmal cyst with focal calcification, and mobile encapsulated adipose tissue can present as a mobile subcutaneous nodule. The features of idiopathic calcinosis presenting as a mobile subcutaneous nodule as well as the characteristics of other benign mobile subcutaneous tumors are reviewed.

Competition between skin antimicrobial peptides and commensal bacteria in type 2 inflammation enables survival of S. aureus.

During inflammation, the skin deploys antimicrobial peptides (AMPs) yet during allergic inflammation it becomes more susceptible to Staphylococcus aureus. To understand this contradiction, single-cell sequencing of Il4ra-/- mice combined with skin microbiome analysis reveals that lower production of AMPs from interleukin-4 receptor α (IL-4Rα) activation selectively inhibits survival of antibiotic-producing strains of coagulase-negative Staphylococcus (CoNS). Diminished AMPs under conditions of T helper type 2 (Th2) inflammation enable expansion of CoNS strains without antibiotic activity and increase Staphylococcus aureus (S. aureus), recapitulating the microbiome on humans with atopic dermatitis. This response is rescued in Camp-/- mice or after topical steroids, since further inhibition of AMPs enables survival of antibiotic-producing CoNS strains. In conditions of Th17 inflammation, a higher expression of host AMPs is sufficient to directly inhibit S. aureus survival. These results show that antimicrobials produced by the host and commensal bacteria each act to control S. aureus on the skin.

Analysis of Cutaneous Lupus Hospitalizations: A United States National Population-Based Study.

Background There are limited studies analyzing cutaneous lupus erythematosus (CLE) hospitalizations. In this study, we aimed to analyze baseline demographics of systemic lupus erythematosus (SLE) and CLE patients, identify the most common reasons for hospitalizations, and find out the hospitalization outcomes.  Materials and methods We performed the analysis using the National (Nationwide) Inpatient Sample (NIS) database between 2016 and 2019. For the CLE cohort, data for adults aged 18 years and older with the primary or secondary diagnosis of CLE using International Classification of Disease - 10th revision (ICD-10) codes were extracted. For comparison, the SLE cohort was identified by patients aged 18 years and older with primary or secondary diagnoses of SLE using ICD-10 codes. Chi-squared test was used to compare baseline demographic characteristics. Multivariable logistic and linear regression was used to calculate outcomes of interest. Results In comparison to the SLE cohort, the CLE cohort was not only older in age and lower percentage female, but also had shorter length of stay, less total hospital charge, and the majority had Medicare as primary insurance. The SLE cohort included predominantly African American patients while the CLE cohort was majority Caucasian patients. The cardiovascular risks were more prevalent in the CLE cohort and most commonly admitted for sepsis, cardiovascular disease, and mental health disorders. Conclusion Our study highlights the importance of outpatient follow-up in CLE patients to closely monitor cardiovascular risk factors, early identification of infections, and routine mental health screenings to reduce hospitalizations and resource utilization.

An Unexpected Case of Malignant Mesothelioma in a Young Woman.

A 41-year-old female with a past medical history significant only for right retinal vein occlusion presented with chest pain, cough, and shortness of breath. After being found to have a large right-sided pleural effusion and undergoing a nondiagnostic thoracentesis, a noncontrast chest computed tomography scan revealed multiple diffuse nodules in the right lung with irregular paraspinal pleural thickening. An extensive workup followed, with computed tomography-guided biopsy ultimately revealing the diagnosis. The following report describes the patient presentation, laboratory findings, and extensive clinical investigation, and provides a discussion of the epidemiology, imaging findings, prognosis, and differential diagnoses for the illness in question.