Augmentation of Transient Donor Cell Chimerism and Alloantigen-Specific Regulation of Lung Transplants in Miniature Swine

Donor alloantigen infusion induces T cell regulation and transplant tolerance in small animals. Here, we study donor splenocyte infusion in a large animal model of pulmonary transplantation. Major histocompatibility complex-mismatched single lung transplantation was performed in 28 minipigs followed by a 28-day course of methylprednisolone and tacrolimus. Some animals received a perioperative donor or third party splenocyte infusion, with or without low-dose irradiation (IRR) before surgery. Graft survival was significantly prolonged in animals receiving both donor splenocytes and IRR compared with controls with either donor splenocytes or IRR only. In animals with donor splenocytes and IRR, increased donor cell chimerism and CD4(+) CD25(high+) T cell frequencies were detected in peripheral blood associated with decreased interferon-γ production of leukocytes. Secondary third-party kidney transplants more than 2 years after pulmonary transplantation were acutely rejected despite maintained tolerance of the lung allografts. As a cellular control, additional animals received third-party splenocytes or donor splenocyte protein extracts. While animals treated with third-party splenocytes showed significant graft survival prolongation, the subcellular antigen infusion showed no such effect. In conclusion, minipigs conditioned with preoperative IRR and donor, or third-party, splenocyte infusions may develop long-term donor-specific pulmonary allograft survival in the presence of high levels of circulating regulatory T cells.

Molecular characterization of Staphylococcus aureus from outpatients in the Caribbean reveals the presence of pandemic clones

Staphylococcus aureus infections continue to pose a global public health problem. Frequently, this epidemic is driven by the successful spread of single S. aureus clones within a geographic region, but international travel has been recognized as a potential risk factor for S. aureus infections. To study the molecular epidemiology of S. aureus infections in the Caribbean, a major international tourist destination, we collected methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates from community-onset infections in the Dominican Republic (n = 112) and Martinique (n = 143). Isolates were characterized by a combination of pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing (MLST) typing. In Martinique, MRSA infections (n = 56) were mainly caused by t304-ST8 strains (n = 44), whereas MSSA isolates were derived from genetically diverse backgrounds. Among MRSA strains (n = 22) from the Dominican Republic, ST5, ST30, and ST72 predominated, while ST30 t665-PVL+ (30/90) accounted for a substantial number of MSSA infections. Despite epidemiological differences in sample collections from both countries, a considerable number of MSSA infections (~10%) were caused by ST5 and ST398 isolates at each site. Further phylogenetic analysis suggests the presence of lineages shared by the two countries, followed by recent genetic diversification unique to each site. Our findings also imply the frequent import and exchange of international S. aureus strains in the Caribbean.

Hypercalcemia and pneumocystis Pneumonia after kidney transplantation: report of an exceptional case and literature review

Pneumocystis jirovecii remains an important pathogen in solid organ transplant recipients. Although the overall incidence may be decreasing, after the adoption of effective prophylactic measures, the risk has not been abolished, and pneumocystis pneumonia (PCP) can be observed even many years after successful transplantation. Hypercalcemia develops frequently after renal transplantation and is commonly associated with preexisting secondary hyperparathyroidism. But the pathogenesis of hypercalcemia occurring later in the course of transplantation may be different, and other disease states, such as malignancy and opportunistic infections, must be considered. Hypercalcemia in conjunction with PCP is being increasingly reported in renal transplant patients. In all the cases, respiratory symptoms were prominent, hypercalcemia was of mild-to-moderate severity, parathyroid hormone concentration was decreased, and 1,25(OH)(2) D levels were extraordinarily or inappropriately high. We report the first case to our knowledge of severe hypercalcemia accompanying PCP, in a patient with previous total parathyroidectomy.

Intentional ABO-incompatible lung transplantation

We report on a case of intentional blood group incompatible lung transplantation. A blood group O cystic fibrosis patient was mechanically ventilated and put on interventional lung assist for severe respiratory decompensation. Since timely allocation of a blood group O donor lung was impossible, an AB deceased donor lung rescue allocation was accepted and the transplant performed using a pre-, peri- and postoperative antibody depletion protocol including plasmapheresis, ivIg administration, rituximab and immunoadsorption. Nine months after the transplant the patient is at home and well.

The dimensionality of Type A behavior within a stressful work simulation

The present study was conducted to examine the dimensionality of overt Type A behaviors elicited in a simulated stressful work environment. University students played a managerial role while being subjected to time and work-load pressures, and completed the Survey of Work Styles (SWS; Jackson & Gray, 1989). Eighteen behaviors, coded by two raters based on audiovisual recordings, yielded relatively high interrater reliabilities. Principal components analysis revealed four primary factors: Hurriedness, Irritability, Tension of the Lower Extremities, and Restlessness. These factors contribute to an understanding of Type A behavior in that they are the first to be derived from a purely observational approach rather than a combination of observational and self-report methods. Consistent with previous research, differential correlations between the factors and the SWS subscales supported a multi-dimensional interpretation of the Type A behavior pattern. Present findings are compared to those of previous studies of Type A dimensionality.