Reply to Bazaz and Denning

Uncoupling of IL-6 signaling and LC3-associated phagocytosis drives immunoparalysis during sepsis

Immune deactivation of phagocytes is a central event in the pathogenesis of sepsis. Herein, we identify a master regulatory role of IL-6 signaling on LC3-associated phagocytosis (LAP) and reveal that uncoupling of these two processes during sepsis induces immunoparalysis in monocytes/macrophages. In particular, we demonstrate that activation of LAP by the human fungal pathogen Aspergillus fumigatus depends on ERK1/2-mediated phosphorylation of p47phox subunit of NADPH oxidase. Physiologically, autocrine IL-6/JAK2/Ninein axis orchestrates microtubule organization and dynamics regulating ERK recruitment to the phagosome and LC3⁺ phagosome (LAPosome) formation. In sepsis, loss of IL-6 signaling specifically abrogates microtubule-mediated trafficking of ERK, leading to defective activation of LAP and impaired killing of bacterial and fungal pathogens by monocytes/macrophages, which can be selectively restored by IL-6 supplementation. Our work uncovers a molecular pathway linking IL-6 signaling with LAP and provides insight into the mechanisms underlying immunoparalysis in sepsis.

Epidermal Growth Factor Receptor Inhibitors and Other Tyrosine Kinase Inhibitors for Solid Tumors

This article analyzes the risk of infection associated with small molecule kinase inhibitors used to treat solid organ malignancies and establishes specific recommendations. Most of these drugs are orally administered and have the ability to inhibit distinct kinases, which play a major role in cancer initiation and progression. Although the true extent of adverse events is not yet known, risk of infection does not seem to be a major problem with these drugs. Because of the limited clinical experience and the constant evolution of targeted therapies, recommendations may evolve in the near future.