Pediatric hematidrosis - A case report and review of the literature and pathogenesis

Hematidrosis is a disorder in which blood-tinged fluid exudes from uninjured skin or mucosa. It is often classified as an eccrine sweat disorder, though the precise mechanism-including involvement of sweat glands-has yet to be proven. In contemporary case reports, hematidrosis appears most frequently in the pediatric population, with 83% of cases in the literature since 2008 occurring in individuals 18 years old or younger. We present here a case of a 10-year-old girl with hematidrosis followed by a review of the literature, with an emphasis on the features of this condition in the pediatric population.

Lymphoid aggregates in desmoplastic melanoma have features of tertiary lymphoid structures

Desmoplastic melanomas (DM) have unique and challenging clinical presentations and histomorphology. A characteristic feature is the presence of scattered lymphoid aggregates. However, the nature of these aggregates is not defined. We hypothesized that they may be tertiary lymphoid structures (TLS), and may be associated with programmed death ligand 1 (PD-L1) expression. We searched our tissue database for 'pure' DMs and for scars as control tissues, collected clinical information, and reviewed H&E histology. We performed multispectral imaging after staining for CD8, CD20, PNAd, FoxP3, CD83, and Ki67, and assessed PD-L1 expression by immunohistochemistry. Pure DM samples were evaluable in 11 patients. All had desmoplastic stroma and lymphoid aggregates on H&E. The lymphoid aggregates of eight of the 11 (72%) DM samples and only three of the 11 scars contained features of TLS, defined as distinct clusters of B cells and CD8 T cells, CD83 dendritic cells in T-cell zones, and PNAd vasculature resembling high endothelial venules. PD-L1 was expressed by at least 1% of melanoma cells in six and by at least 5% of immune cells in 10 of the 11 DM samples. We found that most lymphoid aggregates in DM are organized, classical TLS. PD-L1 expression was detected in most cases and was highest in two cases of DM with TLS. However, low PD-L1 expression in some cases suggests that some DM cells may be unresponsive to interferon-γ. TLS support antigen presentation and T-cell responses in chronic inflammation and cancer. Their presence in DM likely reflects an adaptive immune response, which may be enhanced with immune therapies.

Perivascular Adipose Tissue Harbors Atheroprotective IgM-Producing B Cells

Adipose tissue surrounding major arteries (Perivascular adipose tissue or PVAT) has long been thought to exist to provide vessel support and insulation. Emerging evidence suggests that PVAT regulates artery physiology and pathology, such as, promoting atherosclerosis development through local production of inflammatory cytokines. Yet the immune subtypes in PVAT that regulate inflammation are poorly characterized. B cells have emerged as important immune cells in the regulation of visceral adipose tissue inflammation and atherosclerosis. B cell-mediated effects on atherosclerosis are subset-dependent with B-1 cells attenuating and B-2 cells aggravating atherosclerosis. While mechanisms whereby B-2 cells aggravate atherosclerosis are less clear, production of immunoglobulin type M (IgM) antibodies is thought to be a major mechanism whereby B-1 cells limit atherosclerosis development. B-1 cell-derived IgM to oxidation specific epitopes (OSE) on low density lipoproteins (LDL) blocks oxidized LDL-induced inflammatory cytokine production and foam cell formation. However, whether PVAT contains B-1 cells and whether atheroprotective IgM is produced in PVAT is unknown. Results of the present study provide clear evidence that the majority of B cells in and around the aorta are derived from PVAT. Interestingly, a large proportion of these B cells belong to the B-1 subset with the B-1/B-2 ratio being 10-fold higher in PVAT relative to spleen and bone marrow. Moreover, PVAT contains significantly greater numbers of IgM secreting cells than the aorta. ApoE^−/− mice with B cell-specific knockout of the gene encoding the helix-loop-helix factor Id3, known to have attenuated diet-induced atherosclerosis, have increased numbers of B-1b cells and increased IgM secreting cells in PVAT relative to littermate controls. Immunostaining of PVAT on human coronary arteries identified fat associated lymphoid clusters (FALCs) harboring high numbers of B cells, and flow cytometry demonstrated the presence of T cells and B cells including B-1 cells. Taken together, these results provide evidence that murine and human PVAT harbor B-1 cells and suggest that local IgM production may serve to provide atheroprotection.

Effect of gene expression profile (GEP) testing on clinical management in 19% of consecutively treated patients with stage IB/IIA melanoma at a single institution

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Background: A 31-GEP test is predictive of metastasis in cutaneous melanoma. We hypothesized that GEP testing would “upgrade” surveillance to routine imaging in at least 16% of stage IB/IIA patients, similar to the upgrade rate from sentinel node biopsy. Methods: A GEP score was obtained for consecutive patients with Stage IB/IIA melanoma treated between 6/2014-6/2016. A retrospective review of a prospectively collected database was performed. Results: 67 patients with Stage IB/IIA melanoma met inclusion criteria. In four cases, a GEP result was not available. Of the 63 tested cases, 68% were Stage IB (N = 43), and 32% were Stage IIA (N = 20). A high-risk result was seen in 12% of stage IB (5/43) and 42% of stage IIA (8/19) patients. Insurance denied coverage of scans in 1/13 patients with a high-risk GEP result. The remaining 12 Stage IB/IIA patients with high-risk scores were “upgraded” to high-intensity surveillance. With a median follow-up of 14 months, 1/13 patients with a high-risk GEP result developed distant metastases 21 months after diagnosis of a Stage IIA melanoma. Conclusions: Results from this retrospective single institution study show that GEP testing altered patient management in 19% of Stage IB/IIA patients. Early detection in 1/13 patients with high-risk scores in this series supports further investigation into stratifying traditionally low-risk patients by GEP testing.

Application of a canine 238Pu biokinetics/dosimetry model to human bioassay data

Associated with the use of 238Pu in thermoelectric power sources for space probes is the potential for human exposure, primarily by inhalation and most likely as 238PuO2. Several models have been developed for assessing the level of intake and predicting the resulting radiation dose following human exposure to 239Pu. However, there are indications that existing models do not adequately describe the disposition and dosimetry of 238Pu following human exposure. In this study, a canine model that accounts for these differences has been adapted for use with human excretion data. The model is based on existing knowledge about organ retention of plutonium. An analysis of the sensitivity of the model to changes in aerosol-associated properties indicated that predictions of urinary excretion are most sensitive to changes in particle solubility and diameter and in the ratio of fragment:particle surface area. Application of the model to urinary excretion data from seven workers exposed to a 238Pu ceramic aerosol gave estimated intakes of 390-8,200 Bq and associated initial pulmonary burdens of 80-1,700 Bq. The resulting 50-y dose commitments to critical organs per Bq of 238Pu intake were estimated to be 0.5 mSv for the thoracic region, 0.2 mSv for the liver, and 1 mSv for the bone surfaces.

Alpha-particle-induced p53 protein expression in a rat lung epithelial cell strain

Other investigators have shown that both sparsely ionizing and UV radiation cause cell cycle arrest that is associated with increased expression of wild-type p53 protein. The effect of exposure to alpha-particles from 238Pu on the induction of the p53 protein has now been examined in cultured lung epithelial cells derived from male F344 rats. The number of cells having increased levels of p53 protein was determined by flow cytometry after the cells had been stained with a monoclonal antibody to p53. alpha-Particle irradiation caused a dose-dependent increase in p53 protein levels detectable at doses as low as 0.6 cGy, with no evidence of a threshold. An increase in p53 protein also occurred in X-irradiated cells. However, no increase was seen in cells exposed to less than 10 cGy of X-rays, indicating the existence of a relatively higher DNA damage threshold for sparsely ionizing radiation. In addition, more cells exposed to low doses of alpha radiation had increased p53 protein levels than would be predicted based on the number of nuclei expected to be traversed by an alpha-particle, suggesting that alpha-particles cause genetic damage by mechanisms in addition to direct interactions with DNA.