Anti-PD1/PDL1 induced psoriasis.

BACKGROUND: Immune checkpoint inhibitors are novel agents approved for the treatment of late-stage malignancies. Despite its important clinical benefits, checkpoint inhibition is associated with a unique spectrum of side effects known as immune-related adverse events. Skin toxicities are the most frequent immune-related adverse events during anti-PD1 blockade therapies. Among them, rare cases of psoriasis exacerbation have been reported. METHODS: We present the clinical characteristics of exacerbated psoriasis in 5 patients under anti-PD1/PDL1 therapy. RESULTS: A total of 5 patients were overall included (4 males, 1 female mean age 65.8 years). Among them, 3 were diagnosed with nonsmall cell lung cancer, 1 with papillary urothelial carcinoma, and 1 with squamous cell carcinoma of the tonsil. Of all, 3 patients were treated with anti-PD1 (1 with pembrolizumab, 2 with nivolumab), whereas the remaining 2 with anti-PDL1 (durvalumab). Only 1 out of 5 patients had active psoriatic lesions at the time of treatment initiation, 2 shared a past history of psoriasis, and 1 reported a strong related family history (3/5 siblings). Four out of 5 patients experienced guttate lesions, though the most severe exacerbation was noted in the durvalumab group. Four out of 5 patients managed to continue treatment after close dermatologic monitoring, whereas 1 patient under durvalumab was forced to treatment delays owing to the severity of the skin reactions. Skin rashes appeared in all patients after the fourth cycle of immunotherapy. CONCLUSIONS: Both anti-PD1 and anti-PDL1 therapies can lead to psoriasis exacerbation although more severe flares were noted in patients treated with durvalumab. Not only personal but also related family history of psoriasis are significant risk factors and need to be outlined before treatment initiation. If such related history exists, strict skin surveillance can lead to the early diagnosis and treatment of any psoriatic exacerbations that could otherwise severely affect quality of life or even compromise therapeutic protocols and final prognosis.

Epidermal innervation in healthy children and adolescents.

INTRODUCTION: Epidermal nerve fiber (ENF) density, morphology, and epidermal innervation patterns were examined in children using 2 different techniques, punch biopsy and suction blister. METHODS: Healthy children without symptoms or history of peripheral neuropathy and normal by neurologic examination were studied. Punch biopsy and suction blister specimens were collected from the lateral thigh and distal leg. ENFs were traced from confocal images of immunohistochemically stained samples. Statistical methods included repeated-measures analysis of covariance. RESULTS: Blister and biopsy nerve counts were associated. ENF density in children was dense, lower for older children (P<0.01) and with no difference between boys and girls (P=0.92). Many ENFs appeared multibranched and elongated. CONCLUSIONS: Epidermal innervation in the pediatric population is dense and age-dependent. Blister specimens are less invasive and may provide an alternative to punch biopsy for determining ENF density in children at risk for neuropathy.

Skin and self-injury: a possible link between peripheral innervation and immune function?

The aim of this preliminary case study series was to investigate epidermal innervation in pediatric patients with significant neurological impairment and self-injurious behavior. We enrolled four pediatric patients with self-injury (two males, two females; mean age 12y, range 9-14y) and used archival specimens from healthy, age-matched children with typical development for comparison purposes. Epidermal nerve fiber density, peptide content, and mast cell degranulation patterns from non-damaged skin were tested between the patients and the comparison group. The male patients with self-injury had significantly increased epidermal nerve fiber densities, increased substance P positive fiber count and extensive mast cell degranulation compared with sex- and age-matched individuals with typical development. Our case series shows for the first time altered peripheral innervation from non-damaged tissue in children with significant self-injury and developmental disability compared with a healthy comparison group. Establishing the role of peripheral nociceptive and immune modulatory neural pathways may offer new treatment avenues for this devastating neurobehavioral disorder.

Second-order spatial analysis of epidermal nerve fibers.

Breakthroughs in imaging of skin tissue reveal new details on the distribution of nerve fibers in the epidermis. Preliminary neurologic studies indicate qualitative differences in the spatial patterns of nerve fibers based on pathophysiologic conditions in the subjects. Of particular interest is the evolution of spatial patterns observed in the progression of diabetic neuropathy. It appears that the spatial distribution of nerve fibers becomes more 'clustered' as neuropathy advances, suggesting the possibility of diagnostic prediction based on patterns observed in skin biopsies. We consider two approaches to establish statistical inference relating to this observation. First, we view the set of locations where the nerves enter the epidermis from the dermis as a realization of a spatial point process. Secondly, we treat the set of fibers as a realization of a planar fiber process. In both cases, we use estimated second-order properties of the observed data patterns to describe the degree and scale of clustering observed in the microscope images of blister biopsies. We illustrate the methods using confocal microscopy blister images taken from the thigh of one normal (disease-free) individual and two images each taken from the thighs of subjects with mild, moderate, and severe diabetes and report measurable differences in the spatial patterns of nerve entry points/fibers associated with disease status.

Skin blister and skin biopsy to quantify epidermal nerves: a comparative study.

BACKGROUND: Skin biopsy is an important procedure for the diagnosis of peripheral neuropathy. The main indicators of unmyelinated nerve involvement are decreased density and abnormal morphology of epidermal nerve fibers (ENFs). The suction skin blister is an alternative, less invasive method to visualize and quantify ENFs. The blister roof provides an integrated bird's eye view of all ENFs within one tissue specimen. OBJECTIVE: We compared the suction skin blister method to the punch skin biopsy for evaluation of ENFs. METHODS: Twenty-five volunteers, 35 to 62 years old, without symptoms or history of peripheral neuropathy, and normal by neurologic examination and nerve conduction tests, were studied. One 3 mm punch biopsy and two 3 mm suction blister specimens were collected from the right foot and calf. Comparison between blister and biopsy ENF density was assessed by repeated measures analysis of covariance, accounting for age, gender, and specimen's location. RESULTS: The epidermal roof of the suction skin blister permitted detailed analyses of ENF density, morphology, and distribution across the epidermis and observation of ENF branching pattern. No systematic differences of ENF density were found between skin blisters and biopsies (p = 0.29) or between pairs of blisters from the same location (p = 0.15). ENF density was lower for older subjects (p < 0.01). CONCLUSIONS: The suction skin blister method has potential as a diagnostic tool to investigate small fiber neuropathies. It is a minimally invasive and reliable technique, comparable to skin biopsy for determining epidermal nerve fiber density.