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Twelve research groups participated in the ISOBM TD-3 Workshop in which the reactivity and specificity of 83 antibodies against prostate-specific antigen (PSA) were investigated. Using a variety of techniques including cross-inhibition assays, Western blotting, BIAcore, immunoradiometric assays and immunohistochemistry, the antibodies were categorized into six major groups which formed the basis for mapping onto two- and three-dimensional (2-D and 3-D) models of PSA. The overall findings of the TD-3 Workshop are summarized in this report. In agreement with all participating groups, three main antigenic domains were identified: free PSA-specific epitopes located in or close to amino acids 86-91; discontinuous epitopes specific for PSA without human kallikrein (hK2) cross-reactivity located at or close to amino acids 158-163; and continuous or linear epitopes shared between PSA and hK2 located close to amino acids 3-11. In addition, several minor and partly overlapping domains were also identified. Clearly, the characterization of antibodies from this workshop and the location of their epitopes on the 3-D model of PSA illustrate the importance of selecting appropriate antibody pairs for use in immunoassays. It is hoped that these findings and the epitope nomenclature described in this TD-3 Workshop are used as a standard for future evaluation of anti-PSA antibodies.

Epitope mapping analysis was performed on 53 antibodies submitted to the ISOBM TD-3 PSA Workshop. Western blotting and N-terminal amino acid sequencing, using both native and recombinant human prostate-specific antigen (rPSA), identified four different epitope groups for native PSA. Under reducing conditions native PSA was not recognized by 18/53 antibodies suggesting they reacted with conformation-dependent epitopes. Nine other antibodies reacted with a rPSA polypeptide doublet of 34-35 kD corresponding to different rPSA glycoforms. From sequence mapping studies 22/53 antibodies bound epitopes within amino acid residues 25-85, 3/53 antibodies bound to epitopes within residues 86-220, while 10/53 antibodies bound epitopes within residues 221-261. These results indicate that there are multiple immunogenic epitopes localized on the PSA molecule.

The aim of this study was to compare the incidence of ventilator-associated pneumonia (VAP) and clinical outcome among patients undergoing orthotopic liver transplantation (OLT) admitted to our surgical intensive care unit (ICU). Patients with an ICU stay longer than 4 days who had undergone surgery within 48 hours of admission were included in the study. Patients were subdivided into a liver transplant group (OLT) and no-liver transplant group (noLT). Diagnosis of VAP was based on microbiological data with a positive culture from a sample collected ≥48 hours after admission. VAP was defined as early if the positive culture occurred within the 4th day of admission, and late if after the 4th day. Three hundred seventy-three noLT and 71 OLT patients showed no differences in sex, mean severity score on admission (SAPS II), length of stay, and outcomes. The incidence of VAP was also similar in the 2 groups (27.3% in the noLT group vs 25.3% in the OLT group). Both in the OLT and noLT groups, the VAP patients showed higher (P