Natural killer T (NKT) cells rapidly produce Th1 and Th2 cytokines such as interferon-γ (IFN-γ) and interleukin (IL)-4. This study examined the frequency and function of NKT cells in trauma patients. Frequencies, proliferative responses to α-galactosylceramide (α-GalCer), and Th1/Th2 cytokine secretion levels of NKT cells in peripheral blood mononuclear cells from trauma patients and healthy controls (HC) were measured by flow cytometry. Circulating NKT cell levels were significantly reduced in trauma patients. Proliferation and IFN-γ production of circulating NKT cells in response to α-GalCer were markedly decreased in trauma patients. CD69 expression levels produced by NKT cells were significantly upregulated in trauma patients compared to those in HC. In addition, annexin V+ NKT cells were profoundly increased in trauma patients after α-GalCer stimulation. Trauma patients had higher plasma levels of IL-6, IL-8, and TNF-α compared to HC. In particular, the proliferative response of NKT cells to α-GalCer was significantly decreased in the presence of these cytokines. Such decrease was partially recovered after treatment with blocking antibodies against these cytokines. This study demonstrates that circulating NKT cells are numerically deficient and functionally impaired in IFN-γ production in trauma patients. These findings provide an important insight into the trauma-related innate immune response.

The efficacy and safety of laparoscopy for blunt trauma remain controversial. This systemic review and meta-analysis aimed to evaluate the usefulness of laparoscopy in blunt trauma. The PubMed, EMBASE, and Cochrane databases were searched up to 23 February 2021. Meta-analyses were performed using odds ratios (ORs), standardized mean differences (SMDs), and overall proportions. Overall, 19 studies with a total of 1520 patients were included. All patients were hemodynamically stable. In the laparoscopy group, meta-analysis showed lesser blood loss (SMD −0.28, 95% confidence interval (CI) −0.51 to −0.05, I2 = 62%) and shorter hospital stay (SMD −0.67, 95% CI −0.90 to −0.43, I2 = 47%) compared with the laparotomy group. Pooled prevalence of missed injury (0.003 (95% CI 0 to 0.023), I2 = 0%), nontherapeutic laparotomy (0.004 (95% CI 0.001 to 0.026), I2 = 0%), and mortality (0.021 (95% CI 0.010 to 0.043), I2 = 0%) were very low in blunt trauma. In subgroup analysis, recently published studies (2011–present) showed lesser conversion rate (0.115 (95% CI 0.067 to 0.190) vs. 0.391 (95% CI 0.247 to 0.556), test for subgroup difference: p < 0.01). This meta-analysis suggests that laparoscopy is a safe and feasible option in hemodynamic stable patients with blunt abdominal trauma.

ObjectiveMucosal-associated invariant T (MAIT) cells are a subset of innate-like T cells that are engaged in a number of diseases, but their roles in acute respiratory distress syndrome (ARDS) are not fully examined yet. This study aimed to examine levels and functions of MAIT cells in patients with ARDS.MethodsPeripheral blood samples from patients with ARDS (n=50) and healthy controls (HCs, n=50) were collected. Levels of MAIT cells, cytokines, CD69, programmed cell death-1 (PD-1) and lymphocyte-activation gene 3 (LAG-3) were measured by flow cytometry.ResultsCirculating MAIT cell levels were significantly reduced in patients with ARDS than in HCs. MAIT cell levels were inversely correlated with disease severity and mortality. Cytokine production profiles in MAIT cells showed that percentages of interleukin (IL)-17 producing MAIT cell were significantly higher in patients with ARDS than in HCs. Patients with ARDS exhibited higher expression levels of CD69, PD-1 and LAG-3 in circulating MAIT cells. Moreover, levels of MAIT cells and expression levels of CD69, PD-1 and IL-17 in MAIT cells were higher in bronchoalveolar lavage fluid samples than in peripheral blood samples. Our in vitro experiments showed that MAIT cells triggered macrophages to produce proinflammatory cytokines such as tumour necrosis factor-α, IL-1β and IL-8.ConclusionsThis study demonstrates that circulating MAIT cells are numerically deficient in patients with ARDS. In addition, MAIT cells were found to be activated, migrate into lung, secrete IL-17 and then stimulate macrophages. These findings suggest that MAIT cells contribute to the worsening of inflammation in the lung of patients with ARDS.

BackgroundDendritic cells (DCs) are specialized antigen-presenting cells known to bridge innate and adaptive immune reactions. However, the relationship between circulating DCs and Orientia tsutsugamushi infection is unclear. Therefore, this study aimed to examine the level and function of plasmacytoid DCs (pDCs) and conventional DCs (cDCs), two subsets of circulating DCs, in scrub typhus patients.MethodsThe study included 35 scrub typhus patients and 35 healthy controls (HCs). pDC and cDC levels, CD86 and CD274 expression, and cytokine levels were measured using flow cytometry.ResultsCirculating pDC and cDC levels were found to be significantly reduced in scrub typhus patients, which were correlated with disease severity. The patients displayed increased percentages of CD86+ pDCs, CD274+ pDCs, and CD274+ cDCs in the peripheral blood. The alterations in the levels and surface phenotypes of pDCs and cDCs were recovered in the remission state. In addition, the production of interferon (IFN)-α and tumor necrosis factor (TNF)-α by circulating pDCs, and interleukin (IL)-12 and TNF-α by circulating cDCs was reduced in scrub typhus patients. Interestingly, our in vitro experiments showed that the percentages of CD86+ pDCs, CD274+ pDCs, and CD274+ cDCs were increased in cultures treated with cytokines including IFN-γ, IL-12, and TNF-α.ConclusionsThis study demonstrates that circulating pDCs and cDCs are numerically deficient and functionally impaired in scrub typhus patients. In addition, alterations in the expression levels of surface phenotypes of pDCs and cDCs could be affected by pro-inflammatory cytokines.

Background In patients with blunt injury due to abdominal trauma, the common cause for laparotomy is damage to the small bowel and mesentery. Recently, postoperative early enteral nutrition (EEN) has been recommended for abdominal surgery. However, EEN in patients with blunt bowel and/or mesenteric injury (BBMI) has not been established. Therefore, this study aimed to identify the factors that affect early postoperative small bowel obstruction (EPSBO) and the date of tolerance to solid food and defecation (SF + D) after surgery in patients with BBMI. Methods We retrospectively reviewed patients who underwent laparotomy for BBMI at a single regional trauma center between January 2013 and July 2021. A total of 257 patients were included to analyze the factors associated with enteral nutrition tolerance in patients with EPSBO and the postoperative day of tolerance to SF + D. Results The incidence of EPSBO in patients with BBMI was affected by male sex, small bowel organ injury scale (OIS) score, mesentery OIS score, amount of crystalloid, blood transfusion, and postoperative drain removal date. The higher the mesentery OIS score, the higher was the EPSBO incidence, whereas the small bowel OIS did not increase the incidence of EPSBO. The amount of crystalloid infused within 24 h; the amount of packed red blood cells, fresh frozen plasma, and platelet concentrate transfused; the time of drain removal; Injury Severity Score; and extremity abbreviated injury scale (AIS) score were correlated with the day of tolerance to SF + D. Multivariate analysis between the EPSBO and non-EPSBO groups identified mesentery and small bowel OIS scores as the factors related to EPSBO. Conclusion Mesenteric injury has a greater impact on EPSBO than small bowel injury. Further research is needed to determine whether the mesentery OIS score should be considered during EEN in patients with BBMI. The amount of crystalloid infused and transfused blood components within 24 h, time of drain removal, injury severity score, and extremity AIS score are related to the postoperative day on which patients can tolerate SF + D.

BACKGROUND In trauma patients, bleeding is an immediate major concern. At the same time, there are few cases of acute vascular occlusion after blunt trauma, and it is unclear what assessment and diagnosis should be considered for these cases. Herein, we describe a patient diagnosed with antiphospholipid syndrome after a hypercoagulable workup for acute renal and splenic vascular occlusion due to blunt trauma. CASE SUMMARY A 20-year-old man was admitted to the emergency department with abdominal pain after hitting a tree while riding a sled 10 h ago. He had no medical history. Radiological investigations revealed occlusion of the left renal artery with global infarction of the left kidney and occlusion of branches of the splenic artery with infarction of the central portion of the spleen. Attempted revascularization of the left renal artery occlusion through percutaneous transluminal angioplasty failed due to difficulty in passing the wire through the total occlusion. Considering the presence of acute multivascular occlusions in a young man with low cardiovascular risk, additional laboratory tests were performed to evaluate hypercoagulability. The results suggested a high possibility of antiphospholipid syndrome. Treatment with a subcutaneous injection of enoxaparin was started and changed to oral warfarin after two weeks. The diagnosis was confirmed, and he continued to visit the rheumatology outpatient clinic while taking warfarin. CONCLUSION A hypercoagulable workup can be considered in trauma patients with acute multivascular occlusion, especially in young patients with low cardiovascular risk.

The therapeutic approach for colon injury has changed continuously with the evolution of management strategies for trauma patients. In general, immediate laparotomy can be considered in hemodynamically unstable patients with positive findings on extended focused assessment with sonography for trauma. However, in the case of hemodynamically stable patients, an additional evaluation like computed tomography (CT) is required. Surgical treatment is often required if prominent mesenteric extravasation, free fluid, bowel infarction, and/or colon wall perforation are observed. However, immediate intervention in hemodynamically stable patients without indications for surgical treatment remains questionable. Three patients with colon and mesocolon injuries caused by blunt trauma were treated by nonoperative management. At the time of admission, they were alert and their vital signs were stable. Colon and mesocolon injuries, large hematoma, colon wall edema, and/ or ischemia were revealed on CT. However, no prominent mesenteric extravasation, free fluid, bowel infarction, and/or colon wall perforation were observed. In two cases, conservative treatment was performed without worsening abdominal pain or laboratory tests. Follow-up CT showed improvement without additional treatment. In the third case, follow-up CT and percutaneous drainage were performed in considering the persistent left abdominal discomfort, fever, and elevated inflammatory markers of the patient. After that, outpatient CT showed improvement of the hematoma. In conclusion, nonoperative management can be considered as a therapeutic option for mesocolon and colon injuries caused by blunt trauma of selected cases, despite the presence of large hematoma and ischemia, if there are no clear indications for immediate intervention.

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