Characterization of a model of systemic inflammation in humans in vivo elicited by continuous infusion of endotoxin.

Investigating the systemic inflammatory response in patients with critical illness such as sepsis, trauma and burns is complicated due to uncertainties about the onset, duration and severity of the insult. Therefore, in vivo models of inflammation are essential to study the pathophysiology and to evaluate immunomodulatory therapies. Intravenous bolus administration of endotoxin to healthy volunteers is a well-established model of a short-lived systemic inflammatory response, characterized by increased plasma cytokine levels, flu-like symptoms and fever. In contrast, patients suffering from systemic inflammation are often exposed to inflammatory stimuli for an extended period of time. Therefore, continuous infusion of endotoxin may better reflect the kinetics of the inflammatory response encountered in these patients. Herein, we characterize a novel model of systemic inflammation elicited by a bolus infusion of 1 ng/kg, followed by a 3hr continuous infusion of 1 ng/kg/h of endotoxin in healthy volunteers, and compared it with models of bolus administrations of 1 and 2 ng/kg of endotoxin. The novel model was well-tolerated and resulted in a more pronounced increase in plasma cytokine levels with different kinetics and more prolonged symptoms and fever compared with the bolus-only models. Therefore, the continuous endotoxin infusion model provides novel insights into kinetics of the inflammatory response during continuous inflammatory stimuli and accommodates a larger time window to evaluate immunomodulating therapies.

Risk factors for second primary melanoma among Dutch patients with melanoma.

BACKGROUND: Patients with melanoma are at increased risk of developing subsequent primary melanomas. Knowledge about risk factors for these subsequent primaries is scarce. More evidence may help clinicians in tailoring surveillance schedules by selecting patients who could benefit from intensified surveillance. OBJECTIVES: To identify risk factors for a second primary cutaneous melanoma. METHODS: Possible risk factors for a second primary melanoma were assessed in 1127 patients with cutaneous melanoma who were diagnosed between 2003 and 2011 and completed a baseline questionnaire. Additional data were extracted from the Netherlands Cancer Registry and medical files. RESULTS: Fifty-three patients were diagnosed with a second melanoma during a median follow-up time of 6·3 years. The 5-year cumulative risk was 3·7% and the conditional cumulative risk was 4·6% in years 5-10 after diagnosis. In multivariable analyses, the risk of a second melanoma increased with older age at diagnosis [hazard ratio (HR) 1·03 per year; 95% confidence interval (CI) 1·00-1·06], a high naevus density (HR 7·16, 95% CI 2·89-17·75) and working outside for > 10 years (HR 2·88, 95% CI 1·38-6·03). Patients with invasive melanoma (> 1 mm) had a decreased risk compared with patients with melanoma in situ (HR 0·35, 95% CI 0·13-0·93). CONCLUSIONS: Besides phenotypic characteristics, cumulative sun exposure seemed to increase the risk of a second melanoma. Patients with melanoma in situ may need to be offered follow-up, which is currently not advised. As the risk of a second melanoma did not decline in years 5-10 after diagnosis, a subgroup of patients may need a longer follow-up than is currently advised.