Neuroimmune Mediators of Pruritus in Hispanic Scalp Psoriatic Itch

Scalp psoriatic itch is a common, bothersome, yet understudied, condition with numerous associated treatment challenges. The aim of this study was to enhance our understanding of the pathophysiology of scalp psoriatic itch. Immunohistochemical analysis of known neuroimmune mediators of pruritus was conducted using scalp biopsies from 27 Hispanic psoriatic patients. Patients were categorized into mild/moderate or severe itch groups according to their itch intensity rating of scalp itch. Protease activated receptor (PAR2), substance P, transient receptor potential (TRP)V3, TRPM8 and interleukin-23 expression all correlated  significantly with itch intensity. The pathophysiology of scalp psoriasis is largely non-histaminergic, mediated by PAR2, interleukin-23, transient receptor potential channels, and substance P.

Cyclin D1 expression in Rosai-Dorfman disease: A near constant finding that is not invariably associated with MAPK/ERK pathway activation

Activating mutations in the MAPK/ERK pathway have been shown in nearly half of cases of Rosai-Dorfman disease (RDD). Cyclin D1, a key cell cycle regulator, constitutes a major downstream target of the MAPK/ERK pathway. In this study, we aim to further understand the pathogenesis of RDD by assessing the lesional histiocytes for cyclin D1, p-ERK, Ki-67 and BCL2 by immunohistochemistry We assessed 35 samples of RDD and a control group of histiocyte-rich reactive lesions. Cyclin D1 was expressed in about 90% of cases of RDD. Cyclin D1 was positive in 25-95% (median, 85%) of lesional histiocytes, was moderately/strongly expressed in 97% of cyclin D1-positive cases, and was significantly higher than in control specimens. p-ERK was positive in 16 of 30 (53%) cases of RDD and was negative in all controls. Whereas all p-ERK-positive RDD cases had concurrent cyclin D1 expression, over a third of cyclin D1-positive cases were negative for p-ERK. Ki-67 was low in RDD (median, 3%). BCL-2 was positive in lesional histiocytes in nine of 10 RDD cases assessed and was negative Overall, these findings point to unexpected, potential roles of these molecules in the pathogenesis of RDD. Overexpression of cyclin D1 in the absence of ERK phosphorylation in a subset of RDD cases opens the possibility of oncogenic mechanisms bypassing ERK, and supports the notion that cyclin D1 overexpression in RDD is multifactorial. Moreover, the observed lack of correlation between cyclin D1 with Ki-67 proliferative index suggests that prosurvival actions of cyclin D1 are, at least in part, cell-cycle independent. Finally, expression of BCL-2 and the low Ki-67 index suggest that RDD might be driven by anti-apoptotic rather than pro-proliferative oncogenic mechanisms.

Mutually exclusive recurrent KRAS and MAP2K1 mutations in Rosai-Dorfman disease

Rosai-Dorfman disease is a histiocytic disorder with a poorly defined pathogenesis. Recent molecular studies have revealed recurrent mutations involving genes in the MAPK/ERK pathway in Langerhans cell histiocytosis and Erdheim-Chester disease. However, cases of Rosai-Dorfman disease have rarely been assessed. We performed next-generation sequencing to assess 134 genes on 21 cases of Rosai-Dorfman disease, including 13 women and 8 men with a median age of 43 years (range, 3-82). In all, 13 had extranodal, 5 had nodal, and 3 had coexistent nodal and extranodal disease. The head and neck region was the most common area involved (n=7). Mutation analysis detected point mutations in 7 (33%) cases, including KRAS (n=4) and MAP2K1 (n=3). No mutations were identified in ARAF, BRAF, PIK3CA, or any other genes assessed. Immunohistochemistry demonstrated p-ERK overexpression in 3 cases, all harboring MAP2K1 mutations. Patients carrying mutated genes were younger (median age, 10 vs 53 years, P=0.0347) with more pediatric patients (4/7 vs 1/14, P=0.0251). The presence of mutations correlated with location being more common in the head and neck region; 6/7 (86%) mutated vs 1/14 (7%) unmutated cases (P=0.0009). All 5 (100%) mutated cases with available staging information had a multifocal presentation, whereas only 3/11 (27%) unmutated patients had multifocal disease (P=0.0256). Treatment information was available in 10 patients, including radical resection (n=4), resection and radiation (n=3), and cladribine-based chemotherapy (n=3). With a median follow-up of 84 months (range, 7-352), 7 remained in clinical remission and 3 had persistent disease. No correlation between mutation status and clinical outcome was noted. In summary, we detected mutually exclusive KRAS and MAP2K1 mutations in one-third of cases of Rosai-Dorfman disease suggesting this subgroup are clonal and involve activation of MAPK/ERK pathway. Our data contribute to the understanding of the biology of Rosai-Dorfman disease and point to potential diagnostic and therapeutic targets.

Bone marrow toxicity after yellow phosphorus ingestion

Suicidal ingestions of fireworks containing yellow phosphorus occur often during holidays. A case is reported of a 17 year old woman who intentionally ingested an estimated amount of 5.5 mg of yellow phosphorus, presenting with upper abdominal pain as the only complaint, a physical examination was normal. Blood tests showed a considerable decrease in the granulocyte count; the bone marrow biopsy revealed a decreased cellular mass with degenerative changes. Spontaneous remission was observed during the next 48 hours, with no further complaints.