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El evento embólico (EE) aumenta la morbi-mortalidad de la endocarditis infecciosa (EI). La prevalencia de EE oscila entre 22% y 50%, pudiendo ocasionar hasta el 25% de las muertes de los pacientes que lo presentan. El EE puede ocurrir previamente al diagnóstico, durante el tratamiento o bien posteriormente al mismo. Nuestro objetivo fue analizar las características demográficas, clínicas, microbiológicas, ecocardiográficas y terapeúticas, de pacientes con EI (con y sin embolias) para tratar de establecer variables predictoras del EE. Se realizó en el Hospital Italiano de La Plata, desde marzo de 1996 hasta diciembre de 2004, un estudio descriptivo observacional de una cohorte de pacientes con diagnóstico de EI. Se analizaron en forma retrospectiva 53 pacientes con EI (35 sin EE y 18 con EE). La presencia de vegetación (en el ecocardiograma transtorácico (ETT) y/o en el transesofágico (ETE) al momento del diagnóstico, el tamaño ³ 10 mm y el compromiso de la válvula mitral nativa, fueron las variables en las que existió una asociación estadísticamente significativa con el EE para ser consideradas como predictoras. El tamaño ³ 10 mm fue la única variable asociada a EE en el análisis de regresión logística. Durante el tratamiento antibiótico electivo hubo una reducción de EE, no observándose a partir de la segunda semana.The embolic event (EE) increases the morbidity and mortality of infective endocarditis (IE). Prevalence of EE ranges between 22% and 50%, death rates being up to 25% of patients. EE may occur prior to diagnosis, during treatment or afterwards. The objective of this study was to evaluate the demographic, clinical, microbiological, echocardiographic and therapeutic characteristics in patients suffering from IE (with or without emboli) in order to determine predictors for EE. A descriptive study based on observations of patient population diagnosed with IE was conducted at the Hospital Italiano of La Plata during the period March 1996 - December 2004. Fifty-three patients with IE were analyzed (35 without EE and 18 with EE) in retrospect. We found that the presence of vegetations in the transthoracic (TTE) and/or transesophagic (TEE) echocardiographies at the time of diagnosis, the size ³ 10 mm and the compromise of the native mitral valve were the variables that showed significant statistical association with EE to be considered as predictors. The size ³ 10 mm was the only variable associated with EE in the logistic regression analysis. During the elective antibiotic treatment, there was a reduction in EE, without their being present from the second week onwards.

Aim: All preformed HLA antibodies have a deleterious impact on kidney graft outcome. Alpha and beta chains of DQ and DP molecules can elicit a humoral immune response. Methods: In 191 HLA class II-positive renal transplant recipients we investigated the incidence of DQ and DP alloantibodies by Single antigen beads coated with 29 DQA1/DQB1 and 24 DPA1/DPB1 heterodimers (One Lambda Inc). We also analyzed the putative epitopes for antibody formation by analysis of amino acid sequences of molecules corresponding to detected specificities. All patients were DQA1/DQB1 and/or DPA1/ DPB1 typed by SSP assays. Results: Anti-DQ antibodies were detected in 126 patients. Ninety-four (75%) had had a previous transplant; 14 of these only developed anti-DQ antibodies. Seventy-one percent of patients had anti-DQB1 antibodies, 2% had anti-DQA1 and the remaining 29% had both. As for the epitopes that might determine antibody-patterns development, 28 epitopes were identified (11 for DQA1 and 17 for DQB1); 7 epitopes had not been reported yet (DQA1: 41K/130A0103; 50L02, 03; 52R03, 04, 05, 06; 69T04, 06; 75I01, 02, 03, 04, 06; 160D0302, 0303. DQB1: 87Y05, 0604/05/07/09). Anti-DP antibodies were detected in 64 patients. Fifty-one (80%) had had a previous transplant; 6 of these only developed anti-DP antibodies. Eightyone percent of patients had anti-DPB1 antibodies, 3% had anti-DPA1 and the remaining 16% had both. As for the putative epitopes, we identified 1 epitope characteristic of DPA1 and 10 epitopes characteristic of DPB1 molecules. Nine DPB1 epitopes were located in the 6 hypervariable regions of exon 2 of the DPB1 alleles, while one epitope (96R:*02, 04, 17, 23, 28) was outside of these regions. Conclusions: These data show that both alpha and beta chain epitopes of DQ and DP molecules are immunogenic and indicate the importance of epitope-identification studies.

Incidence and epitope specificity of HLA DQA1 and DQB1 antibodies in renal transplant recipients Antonina Piazza1, Giuseppina Ozzella1, Elvira Poggi1, Daniela Caputo2, Rosa Cremona2, Valentina Imbroglini2, Domenico Adorno1 1C.N.R. - Istituto per i Trapianti d'Organo, Rome, Italy, 2Centro Regionale Trapianti - Lazio, Rome, Italy Since epitopes of HLA molecules represent the binding site of alloantibodies, the exact characterization of HLA antibodies has an important for the management of sensitized renal transplant candidates. The recent development of assays using Single Antigen beads coated with DQ heterodimers (DQA1 and DQB1) permit to distinguish DQA1 from DQB1 alloantibodies. Besides, analyzing the beads' reaction patterns in relation to amino acid sequences of antibody-reactive alleles it is possible to identify DQA1 and DQB1 sensitizing epitopes. In 173 renal transplant candidates showing production of HLA class II antibodies we characterized anti-DQ antibodies using HLA class II Single Antigen beads containing 12 DQA1 and 14 DQB1 alleles variously combined each other. One hundred and four (60%) of the HLA class II positive patients produced anti-DQ antibodies; 88 of the 104 recipients had had a previous transplant. Sixty-eight patients had only anti-DQB1 antibodies, 2 had only anti-DQA1 and the remaining 34 had both anti-DQB1 and anti-DQA1. Anti-DQ positive patients were typed for DQA1 and DQB1 alleles by PCR-SSP technique. Correlating the reaction pattern of each antibody to the amino acid sequences of DQA1/DQB1 alleles, we could identify 9 epitopes characteristic of DQA1 molecules and 14 epitopes characteristic of DQB1. Seven (30%) of these 23 epitopes had not been reported yet; 6 were DQA1-epitopes (41K/130A = DQA1*0103; 160D = DQA1*0302, 0303; 75S/107I/161E/163S/175K = DQA1*05; 50L = DQA1*02, 03; 69T = DQA1*04, 06; 75I = DQA1*01, 02, 03, 04, 06) and one was a DQB1-epitope (87Y = DQB1*05, 0604, 0605, 0607, 0609, . . .). This study, carried out on a large number of HLA-DQA1/DQB1 sensitized patients, confirms the great immunogenicity of mismatched DQ molecules of a renal transplant. Furthermore the characterization of detected HLADQ antibodies allowed us to identify seven unreported epitopes of the DQA1/DQB1 molecules. These findings may be useful in increasing our knowledge of HLA epitope repertoire which can lead to an accurate analysis of high panel reactive antibodies.

Post-transplant development of donor-specific antibodies (DSA) represents a negative prognostic factor in kidney transplantation. This study analysed the impact of posttransplant HLA- and MICA-DSA on kidney graft outcome.