Background: Folliculitis decalvans (FD) is a rare primary neutrophilic scarring alopecia whose etiology has not been completely elucidated yet. Objective: The aim of the study was to determine if the follicular microbiota residing in FD-affected hair follicles had a distinct microbiological signature and if an aberrant immune response was present in the pathogenesis of FD. Methods: We conducted a cross-sectional study of 10 patients affected by FD. Trichoscopy-guided follicular biopsies were taken from affected and healthy scalp to identify the follicular microbiome using next-generation sequencing. We searched for microbiological biomarkers of FD-affected follicles using the linear discriminant analysis (LDA) effect size (LEfSe) tool. Additionally, peripheral blood mononuclear cells were obtained, and their cytokine production was quantified after incubation with pathogen-associated molecular patterns isolated from patients’ biopsies and compared with healthy controls. Results: β-diversity analysis showed statistically significant differences regarding bacteria comparing follicular microbiota of healthy and FD-affected hairs. Ruminococcaceae, Agathobacter sp., Tyzzerella sp., and Bacteriodales vadin HA21 family were good predictors of disease status. IL-10, TNF-α, and IL-6 levels were significantly decreased in patients after incubation with various strains of bacteria compared with controls. Conclusion: FD hair follicles have a specific heterogenous follicular bacterial microbiota signature. Additionally, these patients seem to have an impaired immunological response.

Background: Celiac disease is a gluten-related pathology, highly prevalent and heterogeneous in its clinical presentation, which leads to delays in diagnosis and misdiagnosis. The analysis of duodenal intraepithelial lymphocytes (IELs) by flow cytometry (lymphogram) is emerging as a discriminative tool in the diagnosis of various forms of celiac disease (CD). Aims: The aim of this study was to validate IEL lymphogram performance in the largest adult series to our knowledge, in support of its use as a diagnostic tool and as a biomarker of the dynamic celiac process. Methods: This was a retrospective study including 768 adult patients (217 with active CD, 195 on a gluten-free diet, 15 potential CD patients, and 411 non-celiac controls). The IEL subset cut-off values were established to calculate the diagnostic accuracy of the lymphogram. Results: A complete celiac lymphogram profile (≥14% increase in T cell receptor [TCR]γδ IELs and simultaneous ≤4% decrease in surface-negative CD3 [sCD3⁻] IELs) was strongly associated with active and potential forms in over 80% of the confirmed patients with CD, whereas the remaining patients with CD had partial lymphogram profiles (≥14% increase in TCRγδ or ≤4% decrease in sCD3⁻ IELs), with lower diagnostic certainty. None of these patients had a non-celiac lymphogram. Quantifying the TCRγδ versus sCD3⁻ imbalance as a ratio (≥5) is a discriminative index to discard or suspect CD at diagnosis. Conclusions: We have validated the IEL lymphogram’s diagnostic efficiency (79% sensitivity, 98% specificity), with an LR+ accuracy of 36.2. As expected, the increase in TCRγδ IELs is a reliable marker for celiac enteropathy, while changes in sCD3⁻ IEL levels throughout the dynamic CD process are useful biomarkers of mucosal lesions.

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of relapsed or refractory (r/r) diffuse large B-cell lymphoma (DLBCL); however, a significant proportion of patients fail to achieve a durable response, underscoring the need for reliable predictive biomarkers. We characterize T-lymphocyte subpopulations in apheresis samples from 23 r/r large B-cell lymphoma (LBCL) patients who received axicabtagene ciloleucel (axi-cel) to identify pre-treatment cell biomarkers associated with CAR T-cell kinetics and clinical outcomes. Immunophenotyping of T-cells within fresh apheresis samples and monitoring of circulating CAR T-cells were performed by multiparametric flow cytometry. The median peak CAR T-cell count was 45.2 CAR T-cells/mL. Strong CAR-T expanders (≥45.2 CAR T-cells/mL) exhibited higher values of both CD4⁺ (p = 0.011) and CD8⁺ (p = 0.023) central memory T-cells (T_CM; CCR7⁺CD45RA⁻), as well as lower proportions of CD8⁺CD38⁺ T-cells in apheresis samples. In apheresis, a cut-off value of >4.3% of CD8⁺ T_CM predicted strong CAR-T expansion (AUC: 0.80; p = 0.023) and superior progression-free survival (p = 0.04) compared with patients who had CD8⁺ T_CM below the cut-off. Our data suggest that high frequencies of CD8⁺ T_CM cells in apheresis samples may represent a promising pre-treatment biomarker associated with strong CAR-T expansion and superior clinical outcome in r/r LBCL patients following axi-cel.