Kinetics of Torque Teno Virus Viral Load Is Associated with Infection and De Novo Donor Specific Antibodies in the First Year after Kidney Transplantation: A Prospective Cohort Study.

Torque teno virus (TTV) was recently identified as a potential biomarker for the degree of immunosuppression, and potentially as a predictor of rejection and infection in solid organ transplant patients. We evaluated TTV viral load in kidney transplant (KT) patients during the first year post-transplant to examine overall kinetics and their relationships with deleterious events, including episodes of infection and the formation of de novo donor-specific antibodies (DSAs). In a single-center, prospective observational cohort study, 81 KT patients were monitored at baseline, week 1, and month 1, 3, 6, 9 and 12, post-KT, and whenever required by clinical events. Kidney function, plasma TTV load, immunoglobulins and lymphocyte subpopulations were assessed at each time point. Twenty-six patients (32.1%) presented a total of 38 infection episodes post-KT. Induction immunosuppression with thymoglobulin, compared to basiliximab, was not associated with more infections (p = 0.8093). Patients with infectious events had lower T-cells (p = 0.0500), CD8+ T-cells (p = 0.0313) and B-cells (p = 0.0009) 1 month post-KT, compared to infection-free patients. Patients with infection also showed higher increases in TTV viral loads between week 1- month 1, post-KT, with TTV viral load variations >2.65 log10 cp/mL predicting the development of infectious events during the 12-month study period (p < 0.0001; sensitivity 99.73%; specificity 83.67%). Patients who developed de novo DSAs had lower TTV DNA viral loads at month 12 after KT, compared to patients who did not develop DSA (3.7 vs. 5.3 log10 cp/mL, p = 0.0023). Briefly, evaluating early TTV viremia is a promising strategy for defining infectious risk in the 1st year post-KT. The availability of standardized commercial real-time PCR assays is crucial to further validate this as an effective tool guiding immunosuppression prescription.

Anatomy and Diseases of the Greater Wings of the Sphenoid Bone.

The greater wings of the sphenoid bone (GWS) comprise the components of the sphenoid bone that make up most of the posterior orbital wall and form the anterior and medial parts of the floor of the middle cranial fossa. Many important skull base foramina, which transmit vital neurovascular structures, are present in these paired wings on either side of the central body of the sphenoid bone. A wide variety of diseases can affect the GWS, ranging from benign osseus lesions to malignant primary and secondary bone abnormalities. The complex three-dimensional curved (winged) shape of the GWS and the wide array of pathologic entities that affect this bone can make it challenging for the radiologist to report the imaging findings accurately, especially in relation to the important skull base foramina. The authors describe a systematic approach to understanding the three-dimensional anatomy of the GWS and review important diseases, with the aid of imaging examples. Useful imaging "pearls" that can help in making specific diagnoses are provided throughout the article. ©RSNA, 2022.

The impact of functioning hemodialysis arteriovenous accesses on renal graft perfusion: Results of a pilot study.

INTRODUCTION: After a kidney transplant, it is unknown whether the maintenance of a functioning hemodialysis arteriovenous access could have deleterious effects on renal grafts. We hypothesize that maintaining an arteriovenous access can deviate a significant proportion of the cardiac output from the renal graft. The aim of this study was to investigate whether a temporary closure of the arteriovenous access could lead to an increase in graft perfusion. METHODS: We conducted a study in 17 kidney-transplanted patients with a functioning arteriovenous access. We evaluated, at baseline and 30 s after compression of the arteriovenous access (access flow occlusion), the hemodynamic parameters and the renal resistive index of the graft by Doppler ultrasound. RESULTS: After arteriovenous access occlusion 82.4% (n = 14) of the patients had a decrease in resistive index. All patients had a decrease in heart rate (67 vs 58 bpm, p < 0.001) and 14 (82.4%) had an increase in mean blood pressure (98.3 vs 101.7 mm Hg, p = 0.044). There was a significant decrease in the resistive index (ΔRI) after the access occlusion (0.68 vs 0.64, p = 0.030). We found a negative correlation in Qa (r2 = -0.55, p = 0.022) with the ΔRI, and Qa was an independent predictor of ΔRI in a model adjusted to pre-occlusion resistive index. CONCLUSION: Our results showed that temporary occlusion of an arteriovenous access causes a significant decline in renal graft resistive index and this decline is higher with the occlusion of accesses with higher Qa. These results suggest that the maintenance of arteriovenous accesses, mainly those with higher Qa, can decrease renal graft perfusion.