Kinetics of Neutrophil Subsets in Acute, Subacute, and Chronic Inflammation.

At homeostasis the vast majority of neutrophils in the circulation expresses CD16 and CD62L within a narrow expression range, but this quickly changes in disease. Little is known regarding the changes in kinetics of neutrophils phenotypes in inflammatory conditions. During acute inflammation more heterogeneity was found, characterized by an increase in CD16dim banded neutrophils. These cells were probably released from the bone marrow (left shift). Acute inflammation induced by human experimental endotoxemia (LPS model) was additionally accompanied by an immediate increase in a CD62Llow neutrophil population, which was not as explicit after injury/trauma induced acute inflammation. The situation in sub-acute inflammation was more complex. CD62Llow neutrophils appeared in the peripheral blood several days (>3 days) after trauma with a peak after 10 days. A similar situation was found in the blood of COVID-19 patients returning from the ICU. Sorted CD16low and CD62Llow subsets from trauma and COVID-19 patients displayed the same nuclear characteristics as found after experimental endotoxemia. In diseases associated with chronic inflammation (stable COPD and treatment naive HIV) no increases in CD16low or CD62Llow neutrophils were found in the peripheral blood. All neutrophil subsets were present in the bone marrow during homeostasis. After LPS rechallenge, these subsets failed to appear in the circulation, but continued to be present in the bone marrow, suggesting the absence of recruitment signals. Because the subsets were reported to have different functionalities, these results on the kinetics of neutrophil subsets in a range of inflammatory conditions contribute to our understanding on the role of neutrophils in health and disease.

Predictors of surgical management of high grade blunt splenic injuries in adult trauma patients: a 5-year retrospective cohort study from an academic level I trauma center.

BACKGROUNDS: Splenic injury accounts for 40% of all injuries after blunt abdominal trauma. Blunt splenic injury in hemodynamically unstable patients is preferably treated by splenectomy. Nowadays hemodynamically stable patients with low grade splenic injuries are mostly treated by non-operative management (NOM). However no consensus exists about the management of high grade splenic injuries in hemodynamically stable patients. Therefore the aim of this study was to analyze patients with high grade splenic injuries in our institution. METHODS: We retrospectively included all patients with a splenic injury presented to our level I trauma center during the 5-year period from January 1, 2012, until December 31, 2017. Baseline characteristics, data regarding complications and mortality were collected from the electronic patient registry. Patients were grouped based on splenic injury and the treatment they received. RESULTS: A total of 123 patients were included, of which 93 (75.6%) were male with a median age of 31 (24-52) and a median injury severity score of 27 (17-34). High grade injuries (n = 28) consisted of 20 Grade IV injuries and 8 grade V injuries. Splenectomy was required in 15/28 (53.6%) patients, of whom all remained hemodynamically unstable after resuscitation, including all grade V injuries. A total of 13 patients with high grade injuries were treated with spleen preserving therapy. Seven of these patients received angio-embolization. One patient went for laparotomy and the spleen was treated with a hemostatic agent. Secondary hemorrhage was present in 3 of these patients (initial treatment: 1 embolization/ 2 observational), resulting in a success rate of 76.9%. There is no mortality seen in patient with high grade splenic injuries. CONCLUSION: Non-operative treatment in high grade splenic injuries is a safe treatment modality in hemodynamically stable patients. Hemodynamic status and peroperative bleeding, not injury severity or splenic injury grade were the drivers for surgical management by splenectomy. This selected cohort of patients must be closely monitored to prevent adverse outcomes from secondary delayed bleeding in case of non-operative management.