Sominidi‐Damodaran, Sindhuja

ABSTRACT Tissue‐resident memory T cells (TRMs) are a distinct memory T‐cell subset that permanently reside in tissues such as the skin. In chronic immune‐mediated dermatoses, including psoriasis, atopic dermatitis, and vitiligo, TRMs are implicated in site‐specific “disease memory,” contributing to persistence and relapse at previously affected sites. This review synthesizes emerging concepts on TRMs in chronic inflammatory skin diseases and discusses clinical and translational implications, including TRM‐targeted therapies. Original human, animal, or in vitro studies evaluating TRMs in the pathogenesis or persistence of dermatologic diseases were included. In psoriasis, CD8 + TRMs (CD69 + CD103 + ) persisted in clinically healed skin. For atopic dermatitis, both CD4 + and CD8 + TRMs are implicated in maintaining Th2/Th22 inflammation. In vitiligo, autoreactive CD8 + TRMs at lesional margins mediate melanocyte destruction. Across dermatological diseases, TRMs share three core features: persistence in previously affected skin after clinical resolution, rapid reactivation by diverse triggers (stress, autoantigens, allergens, or cytokines) leading to site‐specific recurrence, and relative resistance to conventional therapies. Together, these properties provide a unifying framework linking tissue immune memory to the chronic, relapsing nature of inflammatory skin diseases. However, the dominant TRM pathways vary by disease, reflecting differences in immune polarization and antigen specificity. Targeting TRMs represents a promising strategy for disease control and serves as a biomarker of residual disease or flare. image

Study Design: A panel of 13 clinicians with experience in dermatology and primary care was assembled to review literature regarding the diagnostic workup of scarring and nonscarring alopecias. The literature for review included clinical trials, meta-analyses, systematic reviews, and previously published guidelines from the last 10 years. After review, the panel drafted a list of consensus statements and then voted on these statements using a modified eDelphi method in order to verify the validity and clarity of each statement. Objective: Our objective, as a panel, was to formulate a clear set of guidelines in the workup of various forms of hair loss by a systematic review of clinical data and literature on the matter. Background: Hair loss is a common and frustrating medical concern for patients worldwide and accounts for significant health care utilization and cost. Moreover, hair loss may present as a symptom of an underlying medical condition requiring attention and treatment. Results: After review, the panel reached a total of 22 consensus statements regarding recommendations for diagnostic testing in the setting of hair loss, 17 of those statements focused on nonscarring alopecias, and 5 statements directed toward scarring alopecias. The statements were evaluated by members of the panel and voted on through a modified eDelphi method and discussed in an open forum. Conclusion: The panel’s review revealed that the diagnostic laboratories and/or scalp biopsy should be considered to varying degrees depending on the type of hair loss at presentation. If there is concern for a scarring process, a biopsy should be strongly considered, while serum laboratory work may be of little benefit. In nonscarring alopecias including alopecia areata, telogen effluvium, and androgenetic alopecia, the literature supports ordering certain serologic tests based on the type of hair loss at presentation.

AbstractBackgroundThe assessment of the sentinel lymph node is a cornerstone of melanoma staging. However, ~80% of sentinel lymph node biopsies (SLNB) are negative and nontherapeutic, and patients are unnecessarily exposed to surgery‐related complications. Here, we gauged the potential of the Merlin assay to reduce SLNB‐associated complications. The Merlin assay uses clinicopathologic variables and tumor gene expression profiling to identify low‐risk patients who may forgo SLNB.MethodsWe utilized the Merlin test development cohort to determine SLNB complication rates for procedures performed between 2004 and 2018 at Mayo Clinic. Complications evaluated were lymphedema, seroma, infection/cellulitis, hematoma, and wound dehiscence. Patients who underwent a completion lymph node dissection were excluded.ResultsA total of 558 patients were included. The overall 90‐day complication rate specific to SLNB (1 year for lymphedema) was 17.4%. The most common complications were seroma (9.3%), infection/cellulitis (4.8%), and lymphedema (4.3%). All three were more common in patients with a lower extremity primary tumor location versus other locations. With Merlin test results applied, SLNB‐related complications would have decreased by 59%.ConclusionSLNB is a safe procedure but carries a significant complication rate. Merlin testing might reduce the need for SLNB and its associated complications.

AbstractBackgroundIntegrins are heterodimeric proteins composed of noncovalently linked ɑ and β subunits which are essential for a wide range of normal physiology and also play prominent roles in cancer. Here we tested whether integrin expression in diagnostic skin biopsies is associated with sentinel lymph node (SLN) metastasis.MethodsWe utilized a cohort of 854 consecutive patients with primary cutaneous melanoma to quantify the expression of β integrin subunits by reverse transcriptase quantitative PCR (RT‐qPCR). In addition, we quantified the expression of β3 integrin by immunohistochemistry (IHC) in a subset of 271 patients by H score. Outcome of interest was SLN biopsy metastasis within 90 days of melanoma diagnosis. Logistic regression analyses were used to develop models for the likelihood of SLN metastasis from molecular, clinical, and histologic variables.Resultsβ3 integrin expression quantified by IHC or RT‐qPCR was associated with SLN metastasis. β1, β5, β6, and β8 integrin expression was not associated with SLN metastasis. The incremental gain in performance of a predictive model which included β3 integrin expression as quantified by IHC in combination with established clinicopathologic variables (Breslow depth and patient age) was limited.Conclusionsβ3 integrin is the principal integrin subunit associated with sentinel lymph node biopsy (SLNb) metastasis in primary cutaneous melanoma. However, β3 integrin H score does not significantly improve models for the likelihood of SLN metastasis over Breslow depth and patient age.