Differential expression of programmed cell death ligand 1 (PD-L1) and inflammatory cells in basal cell carcinoma subtypes.

Few studies have evaluated programmed cell death ligand (PD-L1) expression and lymphocytic infiltrates in Basal Cell Carcinoma (BCC). The objectives of this study are to assess PD-L1 expression and markers of local immune response in nodular, superficial, and morpheaform BCC, and compare it to normal, sun-exposed skin from the periphery of intradermal nevi. This was a retrospective study that included three histological subtypes of BCCs, and sun-exposed skin from the periphery of dermal nevi as quality controls. Tissue microarrays (TMA) were constructed with subsequent staining of H&E and immunohistochemistry (IHC) for CD4, CD8, FOXP3 and PD-L1. Non-automated quantification of the infiltrate in the intratumoral and stromal compartments on TMAs was performed. A total of 115 BCC (39 nodular, 39 morpheaform, and 37 superficial) and 41 sun-exposed skin samples were included (mean age 65.4 years; 52.6% females). BCC showed higher expression of PD-L1 (5.4 vs 0.7%, p < 0.001), CD8 (29.8 vs 19.7%, p = 0.002), and FOXP3 (0.3 vs 0.06%, p = 0.022) compared to sun-exposed skin. There was a higher PD-L1 expression in nodular BCC compared with other subtypes. Low-risk BCC subtypes (superficial and nodular) exhibited more PD-L1 expression in intratumoral and stromal immune infiltrates as compared to high-risk BCC subtypes. As a limitation, no immune cells function was evaluated in this study, only the presence/absence of T-lymphocyte sub-populations was recorded. Substantial differences in both PD-L1 expression and lymphocytic infiltrates were found amongst the histological subtypes of BCC and sun-exposed skin. Highest PD-L1 expression was found in nodular BCCs which suggests a potentially targetable strategy in the treatment of this most common BCC subtype.

Autologous fibroblasts for the treatment of cutaneous loxoscelism: First experience.

Several treatments have been described for cutaneous loxoscelism (CL), but the quality of available evidence is insufficient for the elaboration of a therapeutic consensus. Dapsone has shown beneficial effects on stopping the inflammatory phenomenon and accelerating the recovery. It is recommended to start dapsone once the visceral involvement is ruled out if glucose-6-phosphate dehydrogenase levels are normal. Autologous fibroblast (AF) therapy is a novel therapy that has been successfully used in bioengineering as skin substitutes for surgical wounds and burns, diabetic and pressure ulcers, and other aesthetic purposes. Interestingly, there are no reports of AFs in CL. We present a case of CL in which the necrotic process was stabilised with dapsone, but the healing of the ulcer was not achieved. Three weekly applications of AFs 100 000/cm2 were performed on a biocompatible polymer matrix, with optimal response within 2 months. This represents the first report of AFs in CL, setting the stage for future studies.