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T-helper-17 ([T.sub.H]17) cells have critical roles in mucosal defence and in autoimmune disease pathogenesis (1-3). They are most abundant in the small intestine lamina propria, where their presence requires colonization of mice with microbiota (4-7). Segmented filamentous bacteria (SFB) are sufficient to induce [T.sub.H]17 cells and to promote [T.sub.H]17-dependent autoimmune disease in animal models (8-14). However, the specificity of [T.sub.H]17 cells, the mechanism of their induction by distinct bacteria, and the means by which they foster tissue-specific inflammation remain unknown. Here we show that the T-cell antigen receptor (TCR) repertoire of intestinal [T.sub.H]17 cells in SFB-colonized mice has minimal overlap with that of other intestinal [CD4.sup.+] T cells and that most [T.sub.H]17 cells, but not other T cells, recognize antigens encoded by SFB. T cells with antigen receptors specific for SFB-encoded peptides differentiated into RORγt-expressing [T.sub.H]17 cells, even if SFB-colonized mice also harboured a strong [T.sub.H]1 cell inducer, Listeria monocytogenes, in their intestine. The match of T-cell effector function with antigen specificity is thus determined by the type of bacteria that produce the antigen. These findings have significant implications for understanding how commensal microbiota contribute to organ-specific autoimmunity and for developing novel mucosal vaccines., How SFB induces [T.sub.H]17 cells and how these cells contribute to self-reactive pathological responses remain key unanswered questions. A recent study, using mice with monoclonal TCRs, suggested that induction of [...]

Recent research has associated alopecia areata (AA), an autoimmune disorder, with deficiency of Vitamin D, which regulates immune processes. This retrospective study compared Vitamin D levels in AA patients to those of other alopecia diagnoses and nonalopecia controls. When compared to controls, patients with AA or other alopecia diagnoses did not demonstrate lower Vitamin D levels. However, when compared to other alopecia diagnoses, AA patients had a statistically significantly higher proportion of patients with Vitamin D deficiency and a lower mean Vitamin D level. Our findings suggest a greater association between lower Vitamin D levels and AA compared to other alopecia diagnoses. Further prospective studies investigating Vitamin D levels and supplementation in AA patients are needed to further elucidate this association and its potential relevance. [ABSTRACT FROM AUTHOR]

The article focuses on disparities in melanoma demographics, tumor stage and metastases in Hispanic and Latino patients, presenting a retrospective study that reveals these patients are diagnosed with melanoma at a younger age, have a higher proportion of females and experience more advanced tumor stages, lymph node metastases and distant metastases compared to non-Hispanic and non-Latino White patients, indicating the need for further research and interventions to these healthcare disparities.

A case study of a 71-year-old Hispanic man with a history of vitiligo presented with an acute-onset blistering rash on the face, arms, and hand. Topics include Phototoxic contact dermatitis is an irritant reaction resembling an exaggerated sunburn that occurs with the use of a photosensitizing agent; and detailed history often is necessary to identify the causative agents of phototoxic contact dermatitis.

T-helper-17 (TH17) cells have critical roles in mucosal defence and in autoimmune disease pathogenesis. They are most abundant in the small intestine lamina propria, where their presence requires colonization of mice with microbiota. Segmented filamentous bacteria (SFB) are sufficient to induce TH17 cells and to promote TH17-dependent autoimmune disease in animal models. However, the specificity of TH17 cells, the mechanism of their induction by distinct bacteria, and the means by which they foster tissue-specific inflammation remain unknown. Here we show that the T-cell antigen receptor (TCR) repertoire of intestinal TH17 cells in SFB-colonized mice has minimal overlap with that of other intestinal CD4+ T cells and that most TH17 cells, but not other T cells, recognize antigens encoded by SFB. T cells with antigen receptors specific for SFB-encoded peptides differentiated into RORγt-expressing TH17 cells, even if SFB-colonized mice also harboured a strong TH1 cell inducer, Listeria monocytogenes, in their intestine. The match of T-cell effector function with antigen specificity is thus determined by the type of bacteria that produce the antigen. These findings have significant implications for understanding how commensal microbiota contribute to organ-specific autoimmunity and for developing novel mucosal vaccines. [ABSTRACT FROM AUTHOR]

Background: There are no guidelines on when to more strongly recommend sentinel lymph node biopsy (SLNB) for T1b melanomas., Objective: To examine whether anatomic locations of T1b melanomas and patient age influence metastases., Methods: We conducted a retrospective study using data from two hospitals in Los Angeles County from January 2010 through January 2020., Results: Out of 620 patients with primary melanomas, 566 melanomas were staged based on the American Joint Committee on Cancer 8th edition melanoma staging. Forty-one were T1b, of which 13 were located on the face/ear/scalp and 28 were located elsewhere. T1b melanomas located on the face/ear/scalp had an increased risk of lymph node or distant metastasis compared with other anatomic sites (31% vs 3.6%, P=0.028). For all melanomas, the risk of lymph node or distant metastasis decreased with age of 64 years or greater (P<0.001 and P=0.034). For T1b melanomas, the risk of distant metastasis increased with increasing age (P=0.047)., Limitations: Data were from a single county.  Conclusion: T1b melanomas of the face/ear/scalp demonstrated a higher risk of lymph node or distant metastasis and may help guide the recommendation of SLNB, imaging, and surveillance. Younger patients may be more strongly considered for SLNB and older patients with T1b melanomas may warrant imaging.  J Drugs Dermatol. 2024;23(5):306-310. doi:10.36849/JDD.7667.