Enzyme linked immunosorbent assay (ELISA) as screening method for anti-paternal allo-antibodies in patients with recurrent pregnancy loss (RPL).

OBJECTIVES: Non-HLA-specific anti-paternal antibodies (APA) have been associated with immune responses against HLA-negative trophoblast. As screening for APA by using the flow cytometric cross match (FCXM) is complicated, we evaluated the One Lambda Antigen Tray Test (OLATT) an easy screening method for antibodies in organ transplant recipients. STUDY DESIGN: We randomly selected 92 patients of our recurrent pregnancy loss (RPL)-clinic merely on the basis of having had at least two consecutive miscarriages at <20 weeks representing positive and negative FCXM results. Stored sera were thawed and tested by OLATT. Concordance (Kappa statistic) and conformance (Chi-square test to McNemar) of FCXM and OLATT results were analysed. RESULTS: Of 48 FCXM-positive patients, 38 (79.2%) were positive and 10 (20.8%) negative by OLATT. Out of 44 FCXM negative patients, 37 (84.1%) were negative and 7 (15.9%) positive by OLATT. This resulted in a positive prediction value of 84.4%, a negative prediction value of 78.7% and a highly significant concordance (kappa=0.631 (p<0.0001; 81.5% versus 50%)) and conformance (p=0.23) between FCXM and OLATT in RPL patients. CONCLUSION: Using the OLATT could substitute the FCXM in screening RPL patients for APA and this might help to more closely study the role of APA in human gestation.

Clinical determinants of ventricular sympathetic reinnervation after orthotopic heart transplantation.

BACKGROUND: It has been demonstrated that ventricular sympathetic reinnervation after cardiac transplantation improves exercise performance. The extent of reinnervation increases with time but is variable. Little is known about other influencing factors. METHODS AND RESULTS: Seventy-seven nonrejecting transplant recipients were cross-sectionally studied by PET with the catecholamine analogue C-11 hydroxyephedrine at 4.8+/-3.5 years after transplantation. Results were compared with history-derived parameters related to recipient's clinical course before, during, and after surgery; donor characteristics; and immunogenetics. Partial reinnervation was observed in 52 patients (extent, 21+/-16% of left ventricle). Complete denervation was found in 25 patients at various times after transplantation. Reinnervation extent correlated with time after surgery (r=0.387; P<0.001) but also inversely with donor age (r=-0.309, P=0.006) and recipient age (r=-0.243, P=0.032). Maximal hydroxyephedrine retention correlated inversely with frequency of rejection episodes (r=-0.267, P=0.019), was reduced when aortic complications occurred perioperatively (9 patients), and correlated inversely with aortic cross-clamp time (r=-0.331, P=0.006). Other parameters were not associated with reinnervation. Patients were surveyed for clinical complications over >12 months after PET (until 7.3+/-4.2 years after transplantation), but significant effects of reinnervation on outcome were not observed. CONCLUSIONS: The present data suggest that sympathetic reinnervation after cardiac transplantation is not simply a function of time. Reinnervation is more likely with young age, fast and uncomplicated surgery, and low rejection frequency. Despite few effects on prognosis in otherwise healthy recipients, improved understanding of clinical determinants may contribute to enhance allograft reinnervation and thereby augment exercise capacity in the future.

MYC overexpression imposes a nonimmunogenic phenotype on Epstein-Barr virus-infected B cells.

Lymphoblastoid cell lines, generated by immortalization of normal B cells by Epstein-Barr virus (EBV) in vitro, have strong antigen-presenting capacity, are sensitive to EBV-specific cytotoxic T cells, and are highly allostimulatory in mixed lymphocyte culture. By contrast, EBV-positive Burkitt lymphoma (BL) cells are poor antigen presenters, are not recognized by EBV-specific cytotoxic T cells, and are poorly allostimulatory, which raises the question of whether immunological pressure exerted during BL pathogenesis in vivo has selected for a 'nonimmunogenic' tumor phenotype. The present work addresses this question by examining the immunogenicity/antigenicity of cell lines, generated by conversion of a conditionally immortalized lymphoblastoid cell line to permanent growth independent of EBV-latent proteins by introduction of a constitutively active or tetracycline-regulated c-myc gene (A1 and P493-6 cells, respectively). Compared with its parental lymphoblastoid cell line, A1 cells showed many of the features of the nonimmunogenic BL phenotype, namely poor allostimulatory activity, poor antigen-presenting function associated with impaired proteasomal activity, down-regulation of peptide transporter, reduced HLA class I expression, and an inability to present endogenously expressed EBV-latent proteins to cytotoxic T cells. P493-6 cells, when grown in the presence of estrogen with the exogenous c-myc gene switched off, were strongly immunogenic. The cells had lost their immunogenic potential, however, when grown on a c-myc-driven proliferation program in the absence of estrogen. Deregulation of c-myc, a step central to the development of uncontrolled BL cell growth in vivo, can thus impose a nonimmunogenic phenotype on proliferating human B cells in the absence of any immune pressure.