Supernumerary parathyroid glands (SPGs) are found in 13% of random autopsies. The high incidence of SPGs could explain the persistence or trigger recurrence of renal hyperparathyroidism after surgery. The aim of this study was to assess the frequency and clinical relevance of SPG in patients operated on for renal hyperparathyroidism (HPT). In this retrospective study we reviewed the medical records of 290 patients with renal HPT who were initially treated in our department. We examined the anatomic and pathologic findings during cervical surgical exploration and the outcome of HPT during follow-up. SPGs were identified in 87 patients (30%) during the initial cervicotomy, corresponding to intrathymic parathyroid cell islets (one to four) in 70 cases and to extrathymic SPG in 17 patients. Among 260 patients available for follow-up, 11 experienced persistent HPT (4%), and 34 developed recurrent HPT (13%). A total of 25 patients were reoperated on, and SPGs were responsible for 4 of 8 cases of persistent HPT and 4 of 17 cases of recurrent HPT, representing an overall frequency of 32%. The anatomic distribution of SPGs found during reoperations included thymus, retroesophageal grove, carotid sheath, and mediastinum. SPGs are thus present in 30% of patients with renal HPT and are situated mainly in the thymus. Thymectomy should be performed routinely during the first surgical exploration to prevent recurrences arising from anterior mediastinal glands. SPGs were also responsible for 32% of persistent or recurrent HPT. In that setting, frankly ectopic SPGs are not rare, and preoperative imaging appears highly desirable prior to embarking on surgical reexploration.

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Dialysis patients exhibit an inverse, L- or U-shaped association between blood pressure and mortality risk, in contrast to the linear association in the general population. We prospectively studied 9333 hemodialysis patients in France, aiming to analyze associations between predialysis systolic, diastolic, and pulse pressure with all-cause mortality, cardiovascular mortality, and nonfatal cardiovascular endpoints for a median follow-up of 548 days. Blood pressure components were tested against outcomes in time-varying covariate linear and fractional polynomial Cox models. Changes throughout follow-up were analyzed with a joint model including both the time-varying covariate of sequential blood pressure and its slope over time. A U-shaped association of systolic blood pressure was found with all-cause mortality and of both systolic and diastolic blood pressure with cardiovascular mortality. There was an L-shaped association of diastolic blood pressure with all-cause mortality. The lowest hazard ratio of all-cause mortality was observed for a systolic blood pressure of 165 mm Hg, and of cardiovascular mortality for systolic/diastolic pressures of 157/90 mm Hg, substantially higher than currently recommended values for the general population. The 95% lower confidence interval was approximately 135/70 mm Hg. We found no significant correlation for either systolic, diastolic, or pulse pressure with myocardial infarction or nontraumatic amputations, but there were significant positive associations between systolic and pulse pressure with stroke (per 10-mm Hg increase: hazard ratios 1.15, 95% confidence interval 1.07 and 1.23; and 1.20, 1.11 and 1.31, respectively). Thus, whereas high pre-dialysis blood pressure is associated with stroke risk, low pre-dialysis blood pressure may be both harmful and a proxy for comorbid conditions leading to premature death.

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Major histocompatibility complex (MHC) determinants control antibody production in response to protein antigens. Vaccination with hepatitis B surface antigen (HBsAg) frequently fails in hemodialyzed patients, but the genetic factors that modulate humoral responsiveness are poorly characterized. We studied the distribution of HLA class II alleles in 415 hemodialyzed Caucasian patients who received a full course of HBsAg vaccination, using class II oligotyping after genomic amplification of the DRB1 and DQB1 loci. Phenotype frequencies were compared in 114 non responders (anti-HBs antibodies < or = 10 SI units/liter), 301 responders (anti-HBs antibodies > 10 units/liter) and 471 healthy controls. DRB1*01 (DR1) and DRB1*15 (DR15) frequencies were lower in nonresponders than in responders and controls (DR1, 12.3% vs. 22.9% and 24.8%, respectively; DR15, 14% vs. 22.9% and 25.1%), while DRB1*03 (DR3) and DRB1*14 (DR14) frequencies were higher (DR3, 32.5% vs. 16.6% and 25.3%, respectively; DR14, 9.6% vs. 3% and 6.6%). Overall, 44.5% of DR3 or DR14 patients were nonresponders, compared to 18.1% of DR1 or DR15 patients (P = 0.0001). In conclusion the humoral response to HBsAg vaccine is influenced by class II allelic variants, which differ in their capacity to bind and present peptides to T lymphocytes.