Eliana Nogueira

The use of sirolimus in ganciclovir-resistant cytomegalovirus infections in renal transplant recipients.

Abstract:  Background:  The widespread use of prophylactic ganciclovir and anti‐lymphocyte/thymocyte therapies are associated with increased induction of ganciclovir‐resistant cytomegalovirus (CMV) strains. The use of sirolimus has been associated with a lower incidence of CMV infection in transplant recipients. We questioned whether it could also be effective as a therapeutic treatment of resistant CMV infection.

Improved renal function after kidney transplantation is associated with heme oxygenase-1 polymorphism.

Abstract:  Heme oxygenase‐1 (HO‐1) has a microsatellite polymorphism based on the number of guanosine‐thymidine nucleotide repeats (GT) repeats that regulates expression levels and could have an impact on organ survival post‐injury. We correlated HO‐1 polymorphism with renal graft function. The HO‐1 gene was sequenced (N = 181), and the allelic repeats were divided into subclasses: short repeats (S) (<27 repeats) and long repeats (L) (≥27 repeats). A total of 47.5% of the donors carried the S allele. The allograft function was statistically improved six months, two and three yr after transplantation in patients receiving kidneys from donors with an S allele. For the recipients carrying the S allele (50.3%), the allograft function was also better throughout the follow‐up, but reached statistical significance only three yr after transplantation (p = 0.04). Considering only those patients who had chronic allograft nephropathy (CAN; 74 of 181), allograft function was also better in donors and in recipients carrying the S allele, two and three yr after transplantation (p = 0.03). Recipients of kidney transplantation from donors carrying the S allele presented better function even in the presence of CAN.

Clinical correlations of human cytomegalovirus strains and viral load in kidney transplant recipients.

Little is known about clinical differences associated with cytomegalovirus (CMV) infection by distinct strains in renal transplant patients. Different clinical pictures may be associated with specific viral genotypes, viral load, as well as host factors. The objective of this study was to identify CMV strains to determine viral load (antigenemia), and their correlation with clinical data in renal transplant recipients. Seventy-one patients were enrolled, comprising 91 samples. After selection, polymorphonuclear cells were used to amplify and sequence the gB region of CMV DNA. The sequences were analyzed to ascertain the frequency of different genotypes. Additionally, the results of this study showed that the gB coding gene presents a great variability, revealing a variety of patterns: classical gB1 (1.4%), gB1V (46.4%), classical gB2 (35.2%), gB2V (2.8%), gB3 (1.4%), classical gB4 (4.9%) and gB4V (4.9%). The mean viral load in kidney transplant patient was 75.1 positive cells (1-1000). A higher viral load was observed in patients with genotype 4 infection. Statistically significant differences were detected between gB1 and gB4 (p=0.010), and between gB2 and gB4 (p=0.021). The average numbers of positive cells in relation to clinical presentation were: 34.5 in asymptomatic, 49.5 in CMV associated syndrome and 120.7 in patients with invasive disease (p=0.048). As a group, gB1 was the most frequent strain and revealed a potential risk for developing invasive disease. Viral load also seemed to be important as a marker associated with clinical presentation of the disease.

Toll-like receptors-related genes in kidney transplant patients with chronic allograft nephropathy and acute rejection.

INTRODUCTION Toll-like receptors (TLR) comprehend an emerging family of receptors that recognize pathogen-associated molecular patterns and promote the activation of leukocytes. Surgical trauma and ischemia-reperfusion injury are likely to provide exposure to endogenous ligands for TLR in virtually all kidney transplant recipients. METHODS Macroarray (GEArray OHS-018.2 Series-Superarray) analyses of 128 genes involved in TLR signaling pathway were performed in nephrectomy samples of patients with chronic allograft nephropathy (CAN) and acute rejection (AR, vascular and non vascular). The analysis of each membrane was performed by GEArray Expression Analysis Suite 2.0. RESULTS Macroarray profile identified a gene expression signature that could discriminate CAN and AR. Three genes were significantly expressed between CAN and vascular AR: Pellino 2; IL 8 and UBE2V1. In relation to vascular and non-vascular AR, there were only two genes with statistical significance: IL-6 and IRAK-3. CONCLUSION Vascular and non-vascular AR and CAN showed different expression of a few genes in TLR pathway. The analysis of nephrectomy showed that activation of TLR pathway is present in AR and CAN.

Expression of TLR-4 and -2 in peripheral mononuclear cells in renal transplant patients with TLR-4 gene polymorphism

INTRODUCTION TLR-4 has also been identified as a receptor for endogenous alarmins, which are increased post transplantation. TLR-4 has also been associated with a polymorphism that could impact graft outcome. OBJECTIVE To assess the expression of TLR-4 in kidney transplant patients carrying or not a polymorphism. METHODS TLR-4 polymorphism (A299G/T399I) was studied in 200 renal transplant patients. Healthy volunteers were also enrolled as control group. The polymorphism analysis was performed using restriction enzymes technique (RFLP). Functionality of TLR-4 polymorphism was assessed in samples from controls by quantification of TNF-α after LPS stimulus. TLR-4 and -2 expressions were also analyzed by flow cytometry. RESULTS TLR-4 polymorphism was present in 8.5% of renal transplant patients. This polymorphism was associated with impairment in TNF-α secretion. In general, in renal transplant patients, TLR-4 expression in monocytes and in neutrophils was lower than in health volunteers. TLR-2 and TLR-4 expressions in healthy volunteers with A299G/T399I TLR-4 polymorphism was higher than in wild-type genotype healthy volunteers (p<0.01 and p<0.05, respectively), and also higher than A299G/T399I TLR-4 polymorphism renal transplant patients (p<0.05). TLR-2 expression on neutrophils in wild-type genotype renal transplant patients was higher compared to wild-type genotype healthy volunteers, and was also higher in relation to A299G/T399I kidney transplanted patients (p<0.01). CONCLUSION Stable renal transplant patients with TLR-4 polymorphism have a lower expression of TLR-4 and TLR-2 receptors in peripheral mononuclear cells, which ultimately indicate a less responsiveness for alarmins.

Clinical characteristics and frequency of TLR4 polymorphisms in Brazilian patients with ankylosing spondylitis

OBJECTIVES Innate immunity is involved in the physiopathology of ankylosing spondylitis (AS), with the participation of Gram-negative bacteria, modulation of human leukocyte antigen (HLA) B27 and the involvement of pattern recognition receptors, such as Toll-like receptors (TLRs). The aim of this study was to investigate the clinical characteristics and frequency of TLR4 polymorphisms (Asp299Gly and Thr 399Ile) in a cohort of Brazilian patients with AS. METHODS A cross-sectional study was carried out involving 200 patients with a diagnosis of AS and a healthy control group of 200 individuals. Disease activity, severity and functional capacity were measured. The study of TLR4 polymorphisms was performed using the restriction fragment length polymorphism method. HLA-B27 was analyzed by conventional polymerase chain reaction. The IBM SPSS Statistics 20 program was used for the statistical analysis, with p-values less than 0.05 considered significant. RESULTS Mean age and disease duration were 43.1±12.7 and 16.6±9.2 years, respectively. The sample was predominantly male (71%) and non-Caucasian (52%). A total of 66% of the group of patients were positive for HLA-B27. The sample of patients was characterized by moderate functional impairment and a high degree of disease activity. No significant association was found between the two TLR4 polymorphisms and susceptibility to AS. CONCLUSIONS TLR4 polymorphisms 399 and 299 were not more frequent in patients with AS in comparison to the health controls and none of the clinical variables were associated with these polymorphisms.