Potential Impact of Microarray Diagnosis of T Cell–Mediated Rejection in Kidney Transplants: The INTERCOM Study

We previously developed a microarray‐based test for T cell‐mediated rejection (TCMR) in a reference set of 403 biopsies. To determine the potential impact of this test in clinical practice, we undertook INTERCOM, a prospective international study of 300 indication biopsies from 264 patients ( ClinicalTrials.gov NCT01299168). Biopsies from six centers—Baltimore, Barcelona, Edmonton, Hannover, Manchester and Minneapolis—were analyzed by microarrays, assigning TCMR scores by an algorithm developed in the reference set and comparing TCMR scores to local histology assessment. The TCMR score correlated with histologic TCMR lesions—tubulitis and interstitial infiltration. The accuracy for primary histologic diagnoses (0.87) was similar to the reference set (0.89). The TCMR scores reclassified 77/300 biopsies (26%): 16 histologic TCMR were molecularly non‐TCMR; 15 histologic non‐TCMR were molecularly TCMR, including 6 with polyoma virus nephropathy; and all 46 “borderline” biopsies were reclassified as TCMR (8) or non‐TCMR (38). Like the reference set, discrepancies were primarily in situations where histology has known limitations, for example, in biopsies with scarring and inflammation/tubulitis potentially from other diseases. Neither the TCMR score nor histologic TCMR was associated with graft loss. Thus the molecular TCMR score has potential to add new insight, particularly in situations where histology is ambiguous or potentially misleading.     

Recreational marijuana use is not associated with worse outcomes after renal transplantation

As marijuana (MJ) legalization is increasing, kidney transplant programs must develop listing criteria for marijuana users. However, no data exist on the effect of MJ on kidney allograft outcomes, and there is no consensus on whether MJ use should be a contraindication to transplantation. We retrospectively reviewed 1225 kidney recipients from 2008 to 2013. Marijuana use was defined by positive urine toxicology screen and/or self‐reported recent use. The primary outcome was death at 1 year or graft failure (defined as GFR<20 mL/min/1.73 m²). The secondary outcome was graft function at 1 year. Using logistic regression analyses, we compared these outcomes between MJ users and non‐users. Marijuana use was not associated with worse primary outcomes by unadjusted (odds ratio 1.07, 95% CI 0.45–2.57, P=.87) or adjusted (odds ratio 0.79, 95% CI 0.28–2.28, P=.67) analysis. Ninety‐two percent of grafts functioned at 1 year. Among these, the mean creatinine (1.52, 95% CI 1.39–1.69 vs 1.46, 95% CI 1.42–1.49; P=.38) and MDRD GFR (50.7, 95% CI 45.6–56.5 vs 49.5, 95% CI 48.3–50.7; P=.65) were similar between groups. Isolated recreational MJ use is not associated with poorer patient or kidney allograft outcomes at 1 year. Therefore, recreational MJ use should not necessarily be considered a contraindication to kidney transplantation.     

The motor unit and quantitative electromyography

Electromyography (EMG) assesses the anatomic motor unit (A-MU), but knowledge of its anatomy, physiology, and changes with pathology is limited. The electrophysiological motor unit (E-MU) and its motor unit potential (E-MUP) represents a fraction of the A-MU. Routine EMG assesses a limited number of E-MUP waveform characteristics (metrics) and their magnitudes qualitatively scaled in a nonlinear manner. Another approach is quantitative EMG (QEMG), whereby 20⁺ E-MUPs are extracted and both basic and derived metrics obtained and values expressed quantitatively. In diseased muscle, many E-MUP metrics may be normal, which complicates diagnostic interpretation. In QEMG, E-MUP metrics can be clustered and statistical analyses performed to assign probabilities that E-MUPs (and the muscle) are normal, neuropathic, or myopathic. In this article we review what is known about the A-MU, the restricted E-MU, E-MUP metrics, and what QEMG offers currently and in the future.     

Transcatheter occlusion of ruptured sinus of valsalva aneurysm: innovative use of available technology.

A 9-year-old boy was found to have ruptured sinus of Valsalva aneurysm (RSVA) and aortic coarctation. Following relief of aortic coarctation by balloon angioplasty, transcatheter coil occlusion of the RSVA was performed successfully under transesophageal echocardiographic and fluoroscopic monitoring; bioptome-assisted delivery of 0.052" Gianturco coil was undertaken via a 7 Fr sheath stabilized by an 0.035" guidewire passing through the RSVA and the sheath. This report details the technique of occlusion.