A case of Schnitzler syndrome with unusual immunoglobulin A gammopathy exacerbated by COVID-19 infection.

Schnitzler syndrome (SchS) is a rare autoinflammatory disease characterized by chronic urticarial rash and monoclonal immunoglobulin M (IgM) or IgG gammopathy. Viruses, including COVID-19, activate the innate immune system, therefore SchS, in which the innate immune system is improperly activated, is hypothesized to be exacerbated by viral infection. However, there were no reported SchS cases exacerbated by any viral infection. Here, we report a SchS case with an unusual IgA gammopathy manifested and exacerbated by COVID-19 infection. This report advocates the need for recognizing unusual cases of SchS with monoclonal IgA, and following up on paraprotein like IgA even when it is initially undetectable in cases with SchS symptoms. We also hypothesize that existing autoinflammatory diseases may be exacerbated by COVID-19 infection in the case of a combination of these diseases.

Polypoid Malignant Melanoma with Spontaneous Decapitation Showing Favorable Prognosis: A Case Report.

Introduction: Regression of malignant melanoma (MM) is a commonly observed phenomenon, which refers to disappearance or loss of all or part of MM. It can be identified both clinically and histologically, and high probability of histological regression of MM (10-58%) has been reported. However, the decapitation of skin tumor has rarely been described in the English literature, and decapitation in MM has not been reported. Here, we report the case of polypoid MM with spontaneous decapitation. Case Presentation: An 81-year-old Japanese woman was referred to our hospital due to a polypoid nodule on her cheek. She was diagnosed with MM at stage IIC (T4bN0M0) by histological examinations. Three weeks after the biopsy, the nodule decapitated spontaneously without bleeding, and an ulcer developed on the base of the polypoid nodule. The histological examination of the additionally resected ulcerative lesion under the nodule revealed infiltration of T cells mainly composed of CD8⁺ natural killer T cells. No recurrence or metastasis has been observed for 4 years. Conclusion: This is the first case report of polypoid MM with spontaneous decapitation, which may be attributed to natural killer T cells. Moreover, this case shows favorable prognosis, while it is said that the regression in thick MM does not have prognostic advantage and polypoid topography has been reported to be related to extremely poor prognosis. Further investigations are needed to evaluate the prognostic advantage of decapitation in MM and other skin tumors.

Exploratory study on quantitative assessment of skin hardness in patients with systemic sclerosis using SOFTGRAM.

OBJECTIVES: There is a lack of quantitative and objective methods for measuring skin hardness. This study aimed to verify whether SOFTGRAM, a device that can measure elastic modulus using the Hertz elastic contact theory, could be used to evaluate skin hardness in systemic sclerosis (SSc). METHODS: Skin score according to the modified Rodnan total skin thickness score and elastic modulus of the skin using SOFTGRAM were measured for 20 patients with SSc and 20 healthy controls on 8 parts of the body, both of the cheeks, forearms, fingers, and hands. Five observers shared to measure skin score 320 times (40 participants × 8 parts). Elastic modulus was measured 1600 times (40 participants × 8 parts × 5 times each). As an additional examination to compare differences between observers, the skin score of another healthy control was measured 40 times (5 observers × 8 parts). Elastic modulus was measured 200 times (5 observers × 8 parts × 5 times each). RESULTS: There was a significant correlation between elastic modulus and skin score (correlation coefficient=0.67, p<0.001) and a significant difference in elastic modulus (8 parts: healthy controls vs. limited cutaneous SSc vs. diffuse cutaneous SSc: 22.6±15.7 vs. 32.0±27.7 vs. 44.8±39.8, p<0.001). Intraobserver reliabilities were sufficient in 6 out of 7 observers; however, interobserver was less satisfactory. CONCLUSIONS: This study showed the practicality of SOFTGRAM as an accurate measurement method of skin hardness but also revealed points to be improved. More studies are needed to find an accurate measurement method of skin hardness.

Age-related dysfunction of the DNA damage response in intestinal stem cells.

BACKGROUND: Senescence increases the risks of inflammatory bowel diseases and colon cancer. Intestinal stem cells (ISCs) in crypts differentiate into epithelial cells and thereby maintain intestinal homeostasis. However, the influence of aging on the functions of ISCs is largely unknown. The mutation rate is highest in the small and large intestines. Numerous types of naturally occurring DNA damage are removed by the DNA damage response (DDR). This response induces DNA repair and apoptosis; therefore, its dysregulation leads to accumulation of damaged DNA and consequently cellular dysfunctions, including tumorigenesis. This study investigated whether aging affects the DDR in mouse ISCs. METHODS: Young (2-3-month-old) and old (> 19-month-old) Lgr5-EGFP-IRES-creERT2 mice were irradiated. The DDR in Lgr5-positive ISCs was compared between these mice by immunohistochemical analyses. RESULTS: Induction of DDR marker proteins (phosphorylated ATR and 53BP1), inflammatory factors (phosphorylated NF-κB and interleukin-6), and a mitochondrial biogenesis-associated gene (peroxisome proliferator-activated receptor-γ coactivator 1α) was lower in old ISCs than in young ISCs in vivo. CONCLUSION: The competence of the DDR in ISCs declines with age in vivo.

Functional similarities of microRNAs across different types of tissue stem cells in aging.

Restoration of tissue homeostasis by controlling stem cell aging is a promising therapeutic approach for geriatric disorders. The molecular mechanisms underlying age-related dysfunctions of specific types of adult tissue stem cells (TSCs) have been studied, and various microRNAs were recently reported to be involved. However, the central roles of microRNAs in stem cell aging remain unclear. Interest in this area was sparked by murine heterochronic parabiosis experiments, which demonstrated that systemic factors can restore the functions of TSCs. Age-related changes in secretion profiles, termed the senescence-associated secretory phenotype, have attracted attention, and several pro- and anti-aging factors have been identified. On the other hand, many microRNAs are linked with the age-dependent dysregulations of various physiological processes, including "stem cell aging." This review summarizes microRNAs that appear to play common roles in stem cell aging.