IL-27 regulates the differentiation of follicular helper NKT cells via metabolic adaptation of mitochondria.

Invariant natural killer T (iNKT) cells are innate-like T lymphocytes that express an invariant T cell receptor α chain and contribute to bridging innate and acquired immunity with rapid production of large amounts of cytokines after stimulation. Among effecter subsets of iNKT cells, follicular helper NKT (NKTFH) cells are specialized to help B cells. However, the mechanisms of NKTFH cell differentiation remain to be elucidated. In this report, we studied the mechanism of NKTFH cell differentiation induced by pneumococcal surface protein A and α-galactosylceramide (P/A) vaccination. We found that Gr-1+ cells helped iNKT cell proliferation and NKTFH cell differentiation in the spleen by producing interleukin-27 (IL-27) in the early phase after vaccination. The neutralization of IL-27 impaired NKTFH cell differentiation, which resulted in compromised antibody production and diminished protection against Streptococcus pneumoniae infection by the P/A vaccine. Our data indicated that Gr-1+ cell-derived IL-27 stimulated mitochondrial metabolism, meeting the energic demand required for iNKT cells to differentiate into NKTFH cells. Interestingly, Gr-1+ cell-derived IL-27 was induced by iNKT cells via interferon-γ production. Collectively, our findings suggest that optimizing the metabolism of iNKT cells was essential for acquiring specific effector functions, and they provide beneficial knowledge on iNKT cell-mediated vaccination-mediated therapeutic strategies.

Clinical study of preoperative skeletal muscle mass as a predictor of physical performance recovery following palliative surgery for spinal metastases.

BACKGROUND: Surgical treatment of spinal metastases has been associated with high morbidity and mortality in patients with sarcopenia based on low skeletal muscle mass. We assessed physical performance using the Eastern Cooperative Oncology Group performance status scale and the Barthel Index on the 30th day after palliative surgery for spinal metastases and investigated the effectiveness of surgery according to sarcopenia assessed by skeletal muscle mass. METHODS: We retrospectively analyzed 78 consecutive patients with thoracic and lumbar spinal metastases who underwent palliative surgery. The value of the area of the psoas major muscle at the L3 level normalized by the vertebral area was divided into first, middle, and third tertiles. Clinical variables were compared by tertile. Variables affecting the 30-day good performance status were investigated with univariate and multivariate analyses. RESULTS: The 30-day morbidity rates were 50%, 38.5%, and 15.4% by tertile. The 30-day mortality rate was 2%; all were in the first tertile. Good preoperative performance status scores were seen in 15.4% of first and 50% of third tertile patients. Postoperatively, the performance status improved in all groups, with 30.8%, 65.4%, and 92.3% by tertile. Multivariate regression analysis revealed that a good preoperative performance status (OR: 15.50, 95% CI: 1.610-149.00, P < 0.05) and the value of the area of the psoas major muscle at the L3 level normalized by the vertebral area not in the first tertile (OR: 0.22, 95% CI: 0.06-0.82, P < 0.05) were significant predictors of a good postoperative 30-day performance status. CONCLUSIONS: A good preoperative performance status and exclusion from the first tertile were clinical factors predicting a good postoperative 30-day performance status. In patients with large psoas muscle mass (third tertile), a good 30-day performance status can be expected after surgery, suggesting that surgery in this population should be pursued aggressively.

Factors leading to open revision surgery after trans-sacral canal plasty for lumbar spine disease.

Trans-sacral canal plasty (TSCP) is a minimally invasive lumbar spine surgery under local anaesthesia. TSCP is expected to be effective regardless of whether the patient has had previous surgery. However, there are cases in which open revision surgery is required after TSCP. This study aimed to identify risk factors for open revision surgery after TSCP in order to determine surgical indications and limitations. A retrospective case-control study was conducted in patients who underwent TSCP for lumbar spine disease. Data of 112 patients were analysed. During an observation period of 7-23 months, 34 patients (30.4%) required open revision surgery and 78 (69.6%) did not. The following patient background characteristics were investigated: age, sex, body mass index (BMI), diagnosis, history of spine surgery and the institution where the surgery was performed. Comorbidities were scored using the Elixhauser Comorbidity Index. Preoperative imaging parameters were investigated, including the lesion level (L4/5, L5/S1, other), presence of intervertebral instability, dural sac area, presence of bony stenosis and presence of epidural lipoma. Multivariate analysis revealed that intervertebral instability (odds ratio 2.56, confidence interval 1.00-6.51, p = 0.046) and a narrow dural sac area (odds ratio 0.98, confidence interval 0.97-0.99, p = 0.002) were significant risk factors for open revision surgery after TSCP.

Retroperitoneal Hematoma Due to Drainage Tube Insertion in Extreme Lateral Interbody Fusion: A Case Report.

CASE: A 73-year-old woman presented with degenerative kyphoscoliosis. Radiographs revealed sagittal and coronal imbalance with lumbar spinal stenosis. Extreme lateral interbody fusion (XLIF) was performed in the first stage of 2-stage surgery, and a closed-suction drainage tube was placed in the retroperitoneal cavity. Postoperatively, there was massive bleeding through the tube. Contrast-enhanced computed tomography revealed lumbar artery injury, which required emergency arterial embolization. CONCLUSION: Placing a drainage tube in the retroperitoneal cavity during XLIF surgery can help detect complications such as intestinal and ureteral injuries, the lumbar artery within the lumbar muscle can be injured during drain placement.

Transsacral Canal Plasty for Decompression of Lumbar Spinal Stenosis in a Patient With Epidural Lipomatosis: A Case Report.

CASE: A 58-year-old man presented with lumbar spinal stenosis due to epidural lipomatosis. He underwent transsacral canal plasty (TSCP), in a manner similar to epidural adhesiolysis, which can be performed under local anesthesia. His leg pain improved dramatically in the year after surgery. Furthermore, magnetic resonance images during this time show neural decompression by reduction of the amount of epidural fat. CONCLUSION: TSCP was found not only to relieve pain but also to achieve neural decompression in this patient with spinal canal stenosis caused by lumbar epidural lipomatosis. This is the first report to demonstrate the usefulness of TSCP for spinal epidural lipomatosis.