Interleukin-18 diagnostically distinguishes and pathogenically promotes human and murine macrophage activation syndrome.

Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening hyperferritinemic systemic inflammatory disorders. Although profound cytotoxic impairment causes familial HLH (fHLH), the mechanisms driving non-fHLH and MAS are largely unknown. MAS occurs in patients with suspected rheumatic disease, but the mechanistic basis for its distinction is unclear. Recently, a syndrome of recurrent MAS with infantile enterocolitis caused by NLRC4 inflammasome hyperactivity highlighted the potential importance of interleukin-18 (IL-18). We tested this association in hyperferritinemic and autoinflammatory patients and found a dramatic correlation of MAS risk with chronic (sometimes lifelong) elevation of mature IL-18, particularly with IL-18 unbound by IL-18 binding protein, or free IL-18. In a mouse engineered to carry a disease-causing germ line NLRC4T337S mutation, we observed inflammasome-dependent, chronic IL-18 elevation. Surprisingly, this NLRC4T337S-induced systemic IL-18 elevation derived entirely from intestinal epithelia. NLRC4T337S intestines were histologically normal but showed increased epithelial turnover and upregulation of interferon-γ-induced genes. Assessing cellular and tissue expression, classical inflammasome components such as Il1b, Nlrp3, and Mefv predominated in neutrophils, whereas Nlrc4 and Il18 were distinctly epithelial. Demonstrating the importance of free IL-18, Il18 transgenic mice exhibited free IL-18 elevation and more severe experimental MAS. NLRC4T337S mice, whose free IL-18 levels were normal, did not. Thus, we describe a unique connection between MAS risk and chronic IL-18, identify epithelial inflammasome hyperactivity as a potential source, and demonstrate the pathogenicity of free IL-18. These data suggest an IL-18-driven pathway, complementary to the cytotoxic impairment of fHLH, with potential as a distinguishing biomarker and therapeutic target in MAS.

Preventive effect of kampo medicine (hangeshashin-to, TJ-14) plus minocycline against afatinib-induced diarrhea and skin rash in patients with non-small cell lung cancer.

PURPOSE: Diarrhea and oral mucositis induced by afatinib can cause devastating quality of life issues for patients undergoing afatinib treatment. Several studies have shown that hangeshashin-to (TJ-14) might be useful for chemotherapy-induced diarrhea and oral mucositis. In this study, we investigated the prophylactic effects of TJ-14 for afatinib-induced diarrhea and oral mucositis and minocycline for afatinib-induced skin rash. PATIENTS AND METHODS: First- and second-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors have become the standard first-line treatment in patients with EGFR-mutated non-small cell lung cancer. The incidence of diarrhea was higher with afatinib than with gefitinib, and we conducted a single-arm Phase II study with afatinib. Patients who had previously undergone treatment with afatinib were ineligible. Both TJ-14 (7.5 g/day) and minocycline (100 mg/day) were administered simultaneously from the start of afatinib administration. The primary end point was the incidence of ≥ grade 3 (G3) diarrhea (increase of ≥7 stools/day over baseline) during the first 4 weeks of treatment. The secondary end points were the incidence of ≥ G3 oral mucositis (severe pain interfering with oral intake) and $ G3 skin toxicity (severe or medically significant but not immediately life-threatening). RESULTS: A total of 29 patients (nine men and 20 women; median age, 66 years; performance status, 0/1/2: 18/10/1) were enrolled from four centers. Four patients had undergone prior treatment with chemotherapy, including gefitinib or erlotinib. In all, 20 (68.9%) patients and one (3.4%) patient had diarrhea of any grade and ≥ G3, respectively. One (3.4%) patient had ≥ G3 oral mucositis; no patients had ≥ G3 skin rash. A total of 18 (62%) of the 29 patients achieved a partial response. CONCLUSION: The present study indicated a trend in which TJ-14 reduced the risk of afatinib-induced diarrhea and minocycline reduced the risk of afatinib-induced skin rash.

Exacerbated and prolonged allergic and non-allergic inflammatory cutaneous reaction in mice with targeted interleukin-18 expression in the skin.

Interleukin 18 induces both T helper 1 and T helper 2 cytokines, proinflammatory cytokines, chemokines, and IgE and IgG1 production. A role of interleukin 18 in inflammatory cutaneous reactions is still unclear, however. Here we generated keratin 5/interleukin 18 transgenic mice overexpressing mature murine interleukin 18 in the skin using a human keratin 5 promoter. In the contact hypersensitivity model, trinitrochlorobenzene elicited a stronger ear swelling in keratin 5/interleukin 18 transgenic mice compared with control littermate wild-type or immunoglobulin/interleukin 18 transgenic mice in which mature interleukin 18 was expressed by B and T cells under the control of the immunoglobulin promoter. Application of an irritant, croton oil, induced stronger and more sustained ear swelling in keratin 5/interleukin 18 transgenic mice than in immunoglobulin/interleukin 18 transgenic or wild-type mice. Repetitive topical application (weekly for six consecutive weeks) of trinitrochlorobenzene to their ears also elicited a stronger cutaneous inflammation in keratin 5/interleukin 18 transgenic mice than seen in immunoglobulin/interleukin 18 transgenic or wild-type mice. After these six trinitrochlorobenzene applications, the expression of interferon-gamma, interleukin-4, and CCL20 mRNA in the ear tissue was increased and dermal changes, such as acanthosis and eosinophilic, neutrophilic, and mast cell infiltration, were greater in keratin 5/interleukin 18 transgenic mice than in wild-type mice. Furthermore, the repetitive application elicited a significant increase in serum IgE levels and the number of B cells in the draining lymph node in keratin 5/interleukin 18 transgenic mice. These results suggest that overexpression of interleukin 18 in the skin aggravates allergic and nonallergic cutaneous inflammation, which is accompanied by high expression of T helper 1 and T helper 2 cytokines and chemokines in the skin.