A Role of Staphyococcus aureus, Interleukin-18, Nerve Growth Factor and Semaphorin 3A, an Axon Guidance Molecule, in Pathogenesis and Treatment of Atopic Dermatitis

Staphylococcus aureus (SA) is usually present not only in the skin lesions of atopic dermatitis (AD) but also in the atopic dry skin. SA discharges various toxins and enzymes that injure the skin, results in activation of epidermal keratinocytes, which produce and release IL-18. IL-18 that induces the super Th1 cells secreting IFN-γ and IL-13 is supposed to be involved in development of AD and its pathogenesis. Indeed, the number of SA colonies on the skin surface and the serum IL-18 levels in patients with AD significantly correlated with the skin scores of AD lesions. Also, there is strong positive correlation between the skin scores and serum IL-18 levels in DS-Nh mice (P<0.0001, r=0.64), which develop considerable AD-like legions when they are housed under conventional conditions, but develop skin legions with less severity and less frequency under specific pathogens free (SPF) conditions. Therefore, they are well-known as model mice of AD, in which SA is presumed to be critical factor for the development of AD lesions. Also, theses DS-Nh mice pretreated with Cy developed more remarkable AD-like lesions in comparison with non-treated ones. The levels of INF-r and IL-13 in the supernatants of the lymph node cell cultures stimulated with staphylococcal enterotoxin B (SEB) or ConA were increased in the Cy-treated mice, although the serum levels of total IgE were not. In this experiment, we revealed that Cy-treated mice, to which CD25 +CD4 + reguratory T cells taken from non-treated ones had been transferred, developed the AD-like legions with less severity and less number of SA colonies on the skin surface. Therefore, it is presumed that CD25 +CD4 + reguratory T cells might be involved in the suppression of super Th1 cells which are induced by IL-18 and are involved in the development of AD-like lesions rather than IgE production. The efficient induction of CD25 +CD4 + reguratory T cells is expected for the new type of treatment of AD. We also found that farnesol (F) and xylitol (X) synergistically inhibited biofilm formation by SA, and indeed the ratio of SA in total bacteria at sites to which the FX cream containing F and X had been applied was significantly decreased 1 week later, accompanied with improvement of AD, when compared with that before application and at placebo sites. Therefore, the FX cream is a useful skin-care agent for atopic dry skin colonized by SA. The nerve growth factor (NGF) in the horny layer (the horn NGF) of skin lesions on the cubital fossa was collected by tape stripping and measured using ELISA in AD patients before and after 2 and 4 weeks treatments. Simultaneously, the itch and eruptions on the whole body and on the lesions, in which the horn NGF was measured, were recorded, and also the peripheral blood eosinophil count, serum LDH level and serum total IgE level were examined. The level of NGF was significantly higher in AD patients than in healthy controls, correlated with the severity of itch, erythema, scale/xerosis, the eosinophil count and LDH level, and also significantly decreased after treatments with olopatadine and/or steroid ointment for 2 and 4 weeks. Therefore, the measurement of the NGF by this harmless method seems to be useful to assess the severity of AD and the therapeutic effects on AD. In AD patients, C-fiber in the epidermis increase and sprout, inducing hypersensitivity, which is considered to aggravate the disease. Semaphorin 3A (Sema3A), an axon guidance molecule, is a potent inhibitor of neurite outgrowth of sensory neurons. We administered recombinant Sema3A intracutaneously into the skin lesions of NC/Nga mice, an animal model of AD, and investigated the effect of Sema3A on the skin lesions and their itch. Sema3A dose-dependently improved skin lesions and attenuated the scratching behavior in NC/Nga mice. Histological examinations revealed a decrease in the epidermal thickness, the density of invasive nerve fibers in the epidermis, inflammatory infiltrate including mast cells and CD4 +T cells, and the production of IL-4 in the Sema3A-treated lesions. Because the interruption of the itch-scratch cycle likely contributes to the improvement of the AD-like lesions, Sema3A is expected to become a promising treatment of patients with refractory AD

Statistical Analysis of Stevens-Johnson Syndrome Caused by Mycoplasma pneumonia Infection in Japan

Background: Stevens-Johnson syndrome (SJS) associated with Mycoplasma pneumoniae (M. pneumoniae) infection is mainly observed in children. In adults, drugs are a major cause of SJS, but some adult patients with SJS are infected with M. pneumoniae. We analyzed patients with SJS associated with M. pneumoniae infection to elucidate the differences between drug-induced SJS and M. pneumoniae-associated SJS and also to study differences between M. pneumoniae-associated SJS in children and adults. Methods: This is a retrospective review of Japanese patients who have been reported as M. pneumoniae-associated SJS in medical Journals published from 1981 to 2009, compared with data of Japanese patients with drug-induced SJS reported from 2000 to 2009. Results: Thirty-eight cases of M. pneumoniae-associated SJS and 78 cases of drug-induced SJS were analyzed in this study. Ocular lesions were observed more frequently in M. pneumoniae-associated SJS than in drug-induced SJS (p < 0.01), and adult patients showed a higher ratio of sequelae in their eyes than did patients under 20 years of age (p < 0.01). Sixty-six percent of adult patients with M. pneumoniae-associated SJS developed fever/respiratory symptoms and mucocutaneous lesions on the same day. In contrast, most of the patients under 20 years of age developed fever/respiratory symptoms before mucocutaneous involvement. This means that these adult patients were infected and immunized previously and developed allergic reactions to M. pneumoniae soon after the later infection. Conclusions: In order to prevent ocular sequelae in adult patients when M. pneumoniae infection is suspected, more intensive treatment may be needed in adult patients than in younger patients

Retrospective analysis of Stevens–Johnson syndrome and toxic epidermal necrolysis in 87 Japanese patients – Treatment and outcome

Background: Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare but severe adverse drug reactions with high mortality. Methods: To present the clinical characteristics of SJS and TEN in Japan and evaluate the efficacy of treatments, we retrospectively analyzed cases of SJS and TEN treated in 2 university hospitals during 2000–2013. Results: Fifty-two cases of SJS (21 males and 31 females; average age, 55.1 years) and 35 cases of TEN (17 males and 18 females; average age, 56.6 years) were included in this study. Twenty-eight cases of SJS (53.8%) and all cases of TEN were caused by drugs. Hepatitis was the most common organ involvement in both SJS and TEN. Renal dysfunction, intestinal disorder, and respiratory disorder were also involved in some cases. The major complication was pneumonia and sepsis. All cases except for 3 cases were treated systemically with corticosteroids. Steroid pulse therapy was performed in 88.6% of TEN. Plasmapheresis and/or immunoglobulin therapy was combined with steroid therapy mainly in TEN after 2007. The mortality rate was 6.9% and the rates for SJS and TEN were 1.9% and 14.3%, respectively. These were much lower than predicted mortality according to a severity-of-illness scoring system for TEN prognosis (SCORTEN) score. When comparing the mortality rate between 2000–2006 and 2007–2013, it was decreased from 4.5% to 0.0% in SJS and from 22.2% to 5.3% in TEN. Conclusions: Treatment with steroid pulse therapy in combination with plasmapheresis and/or immunoglobulin therapy seems to have contributed to prognostic improvement in SJS/TEN

Utility of Comprehensive Genomic Profiling Tests for Patients with Incurable Pancreatic Cancer in Clinical Practice

Although comprehensive genomic profiling (CGP) tests have been covered under the Japanese national health insurance program since 2018, the utility and issues of CGP tests have not been clarified. We retrospectively reviewed 115 patients with incurable pancreatic cancer (IPC) who underwent CGP tests in a Japanese cancer referral center from November 2019 to August 2021. We evaluated the results of CGP tests, treatments based on CGP tests, and survival time. Eight cases (6.9%) were diagnosed as tumor mutation burden-high (TMB-H) and/or microsatellite instability-high (MSI-H). The gene mutation rates of KRAS/TP53/CDKN2A/SMAD4 were 93.0/83.0/53.0/25.2%, respectively. Twenty-five patients (21.7%) had homologous recombination deficiency (HRD)-related genetic mutations. Four patients (3.5%) having TMB-H and/or MSI-H were treated with pembrolizumab, and only two patients (1.7%) participated in the clinical trials. Patient characteristics were not significantly different between patients with and without HRD-related gene mutations. The median OS was significantly longer in the HRD (+) group than in the HRD (−) group (749 days vs. 519 days, p = 0.047). In multivariate analysis, HRD-related gene mutation was an independent prognostic factor associated with favorable OS. CGP tests for patients with IPC have the potential utility of detecting HRD-related gene mutations as prognostic factors as well as a therapeutic search