Avances en las enfermedades infecciosas del trasplante de órgano sólido.

Student thesis: Doctoral thesis

Abstract

The objective of this doctoral thesis is to evaluate the direct effects caused by difficult-to-treat bacterial infections and the modulation of the immune response caused by viral infections in solid organ transplant recipients. Three studies have been carried out for this purpose. The first study was based on the hypothesis that antibody-mediated rejection or its treatment predisposes the subsequent cytomegalovirus (CMV) and BK virus replication in kidney transplant recipients. A retrospective case-control study was conducted in Vall d’Hebron University Hospital. Adult renal transplant recipients diagnosed with antibody-mediated rejection during the years 2007-2015 were selected as cases (58). Previous and subsequent transplant recipients were selected as controls (118 controls). CMV replication was significantly more frequent in cases (9/58, 15.5%) than in controls (7/116, 6%) (OR 4.21; 95% confidence interval (CI) 1.10-16.16). In the conditional logistic regression multivariate analysis, after adjusting for statistically significant variables, a higher OR of CMV replication was observed in cases than in controls (2.41), but without a statistically significant difference (95% CI 0.49-11.73, p=0.28). Therefore, the conclusion is that antibody-mediated rejection in kidney transplant recipients may increase the subsequent risk of CMV but for BK virus replication. The second study was based on the hypothesis that infections caused by respiratory viruses in lung transplant recipients are associated with chronic lung allograft dysfunction (CLAD). To study this hypothesis, we performed a prospective cohort study of 98 lung transplant recipients with a prolonged follow-up period. In this cohort of patients, respiratory viruses were systematically detected through nasopharyngeal smears. Thirty-eight (38.8%) patients were diagnosed with CLAD after a median time of 20.4 months (interquartile range 12-30.4). In a time-controlled multivariate Cox analysis, lower respiratory tract infection by respiratory viruses (HR 3.00, CI 1.52-5.91; p=0.002), CMV pneumonitis (HR 3.76, CI 1.23-11.49; p=0.02) and acute rejection (HR 2.97, CI 1.51-5.83; p=0.002) were independent risk factors associated with developing CLAD. In conclusion, lower respiratory tract infections by respiratory viruses are an independent risk factor associated with developing CLAD. Finally, the objective of the third study was to describe the clinical characteristics and outcomes of lung transplant recipients with respiratory isolation of Corynebacterium spp. We performed a retrospective analysis of lung transplant recipients who presented respiratory isolation of Corynebacterium spp. between 2014-2016. Of 527 patients, 24 (4.6%) presented respiratory isolation of Corynebacterium spp. The most frequent species were C. striatum 11/24, C. pseudodiphtheriticum 3/24 and C. amycolatum 3/24. In all patients who underwent bronchoscopy (19/24), abnormalities were observed: mucosal plaques at the bronchial suture (10/19) and purulent secretions (9/19). Clinical cure was achieved in 8/12 (67%) patients diagnosed with tracheobronchitis. Patients with a bronchial stent presented more frequently isolation of Corynebacterium spp. (6/21, 29%) than the rest of patients (18/506, 4%, p
Date of Award29 Oct 2019
Original languageSpanish
SupervisorJuan Gavalda Santapau (Director), Oscar Manuel Len Abad (Director) & Carlos Pigrau Serrallach (Tutor)

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