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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A scientist is studying the process by which innate immune cells are able to respond to damage and pathogen infiltration. Specifically, she examines patients with an immunodeficiency where they are unable to respond to local infections. She notices that these patients do not produce pustulant fluid and do not have recruitment of immune cells in the first several hours of inflammation. Examining neutrophils within these patients reveals that they are able to slow their movement in a flow chamber by loosely attaching to purified vessel tissues. Subsequently, she shows that the neutrophils attach tightly to these vessel walls and move across the walls to the other side. Finally, when different levels of pathogenic proteins are placed on two sides of a purified vessel wall, the neutrophils from this patient do not exhibit a preference between the two sides. The step of neutrophil recruitment that is most likely defective in this patient involves which of the following mediators?
assistant
C5a