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Objectives: The purpose of this study was to identify the patient, injury, and treatment factors associated with infection of bicondylar plateau fractures and to evaluate whether center variation exists., Design: Retrospective review., Setting: Eighteen academic trauma centers., Patients/participants: A total of 1,287 patients with 1,297 OTA type 41-C bicondylar tibia plateau fractures who underwent open reduction and internal fixation were included. Exclusion criteria were follow-up less than 120 days, insufficient documentation, and definitive treatment only with external fixation., Intervention: Open reduction and internal fixation., Main Outcome Measurements: Superficial and deep infection., Results: One hundred one patients (7.8%) developed an infection. In multivariate regression analysis, diabetes (DM) (OR [odds ratio] 3.24; P ≤ 0.001), alcohol abuse (EtOH) (OR 1.8; P = 0.040), dual plating (OR 1.8; P ≤ 0.001), and temporary external fixation (OR 2.07; P = 0.013) were associated with infection. In a risk-adjusted model, we found center variation in infection rates (P = 0.030)., Discussion: In a large series of patients undergoing open reduction and internal fixation of bicondylar plateau fractures, the infection rate was 7.8%. Infection was associated with DM, EtOH, combined dual plating, and temporary external fixation. Center expertise may also play a role because one center had a statistically lower rate and two trended toward higher rates after adjusting for confounders., Level of Evidence: Level IV-Therapeutic retrospective cohort study., (Copyright © 2022 by the American Academy of Orthopaedic Surgeons.)

NK cells are innate immune lymphocytes that express a vast repertoire of germ-line encoded receptors for target recognition. These receptors include inhibitory and activating proteins, among the latter of which is CD16, a low affinity binding Fc receptor. Here, we show that human NK cells expand in response to stimulation with various tumor cell lines. We further demonstrate that the tumor-derived expansion of NK cells is accompanied by rapid, cell-dependent, changes in CD16 expression levels. We show that in NK cells expanded in response to the EBV-transformed cell line 721.221, CD16 is shed and therefore approximately half of the expanded 721.221-derived NK-cell population does not express CD16. We also show, in contrast, that in response to 1106mel cells, CD16 expression is maintained on the cell surface of the expanded NK cells due to an antibody-dependent mechanism. Our results may provide a basis for the selective expansion of NK cells that may be used for tumor immunotherapy., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)