Sandra Cecília Botelho Costa

Use of a nested polymerase chain reaction (N-PCR) to detect Trypanosoma cruzi in blood samples from chronic chagasic patients and patients with doubtful serologies

Chagas disease, caused by Trypanosoma cruzi, is an important endemic illness in Latin America. Serologic tests for T. cruzi detection in blood are sensitive, but their specificity is unsatisfactory. Direct detection of parasites in blood, either by xenodiagnosis or hemoculture, is highly specific but of low sensitivity. Molecular assays such as the Polymerase chain reaction (PCR), which amplifies certain repetitive sequences of nuclear DNA has been used as a good alternative tool for T. cruzi detection in human blood. The present study aimed to test PCR diagnosis in chagasic chronic patients and doubtful serologic patients attended in GEDOCH (Chagas Disease Study Group/UNICAMP, Brazil). A 149 bp fragment originated from nuclear DNA was specifically detected in chronic chagasic patients. The results of these tests were compared with serologic diagnosis performed using standard techniques and xenodiagnosis. We found that 43 out of 50 patients previously serodiagnosed as chagasic were positive using the N-PCR method. Thirteen of 30 patients with doubtful serologic results were confirmed as positive by N-PCR. Our results suggest that the N-PCR may be a complementary tool to serology in the diagnosis of Chagas disease, and that it is usefull for parasite detection in patients with chronic disease and patients with doubtful serologic results.

Trypanosoma cruzi: parasite persistence in tissues in chronic chagasic Brazilian patients

Chagas disease in the chronic phase may develop into cardiac and/or digestive forms. The pathogenesis of the disease is not yet clear and studies have been carried out to elucidate the role of parasite persistence in affected organs. The aim of this study was to detect and quantify Trypanosoma cruzi in paraffin-embedded tissue samples from chronic patients using NPCR (nested polymerase chain reaction) and QPCR (quantitative polymerase chain reaction) methods. These results were correlated to anatomopathological alterations in the heart and gastrointestinal tract (GIT). Of the 23 patients studied, 18 presented the cardiac form and five presented the cardiodigestive form of Chagas disease. DNA samples were randomly isolated from formalin-fixed paraffin-embedded sections of heart and GIT tissue of 23 necropsies and were analyzed through NPCR amplification. T. cruzi DNA was detected by NPCR in 48/56 (85.7%) heart and 35/42 (83.3%) GIT samples from patients with the cardiac form. For patients with the cardiodigestive form, NPCR was positive in 12/14 (85.7%) heart and in 14/14 (100%) GIT samples. QPCR, with an efficiency of 97.6%, was performed in 13 samples (11 from cardiac and 2 from cardiodigestive form) identified previously as positive by NPCR. The number of T. cruzi copies was compared to heart weight and no statistical significance was observed. Additionally, we compared the number of copies in different tissues (both heart and GIT) in six samples from the cardiac form and two samples from the cardiodigestive form. The parasite load observed was proportionally higher in heart tissues from patients with the cardiac form. These results show that the presence of the parasite in tissues is essential to Chagas disease pathogenesis.

INFECTION BY CYTOMEGALOVIRUS IN PATIENTS WITH NEONATAL CHOLESTASIS

BACKGROUND Neonatal cholestasis syndrome with an intra or extrahepatic origin has been associated to viral infections. The participation of the cytomegalovirus in the etiopathogenesis of neonatal hepatitis has been already known for some time, but only recently there have been indications that this virus may be one of the possible etiological factors for extrahepatic biliary atresia. AIMS To assess the prevalence of infection by cytomegalovirus in patients with intrahepatic cholestasis and extrahepatic cholestasis. To compare the clinical characteristics of the intrahepatic cholestasis and extrahepatic cholestasis groups with the cytomegalovirus serological results. Patients and Methods - This study consisted of 76 patients with neonatal cholestasis who were admitted between January 1980 and January 1999 when they underwent a cytomegalovirus serologic study using the ELISA method. A case note was kept on each patient with the following data: age of patient at admission, serologic result for cytomegalovirus, history of maternal infection, prematurity, fetal distress, birth weight, ponderal gain, choluria and fecal acholia. The final anatomic diagnosis of cholestasis was based on the results of an abdominal ultrasonography, a liver biopsy and its evolution. The patients were then divided into two groups: group I - intrahepatic cholestasis and group II - extrahepatic cholestasis. Each of these groups were then divided into two subgroups: subgroup A - positive serology (IgM) for cytomegalovirus and subgroup B - negative serology (IgM) for cytomegalovirus. RESULTS The frequency of positive serology (IgM) for cytomegalovirus was 29.4% in children with intrahepatic cholestasis and 28.5% in children with extrahepatic cholestasis. In comparison with group IIB, group IIA presented a higher rate of maternal infection history. The patients in group IIA demonstrated a delayed access to the service in comparison with group IA. The groups did not demonstrate any significant differences regarding the onset age of jaundice, choluria and fecal acholia, birth weight and ponderal gain. CONCLUSIONS The positive (IgM) seroprevalence for cytomegalovirus in children with intrahepatic cholestasis and extrahepatic cholestasis is high. The history of maternal infection was more common in extrahepatic cholestasis patients with positive serology for cytomegalovirus. There was a delay in the referral of these patients which resulted in a late diagnosis and surgical treatment.

Characterization of bovine respiratory syncytial virus isolated in Brazil

This paper presents the first isolation of bovine respiratory syncytial virus in Brazil and its physicochemical, morphological and molecular characterization. The virus was isolated from 33 samples of nasotracheal secretions, successively inoculated into a Madin-Darby bovine kidney cell culture, which was characterized by physicochemical tests and morphological observation by electron microscopy. The Brazilian sample is an RNA pleomorphic, enveloped, thermolabile and non-hemagglutinating spicular virus. Reverse transcription, followed by nested polymerase chain reaction (nRT-PCR) assay was carried out using oligonucleotides B1, B2A, B3 and B4 for the fusion proteins (F) and B5A, B6A, B7A and B8 for the attachment protein (G). The nRT-PCR-F amplified a fragment of 481 bp corresponding to part of the gene that codes for protein F, whereas nRT-PCR-G amplified a fragment of 371 bp, in agreement with part of the G gene. The virus isolated from Brazilian samples in this study corresponded to the bovine respiratory syncytial virus, and RT-PCR proved to be useful for the diagnosis of bovine clinical samples.

Polyarteritis Nodosa and Cytomegalovirus: Diagnosis by Polymerase Chain Reaction

Abstract: We investigated the occurence of an active cytomegalovirus (CMV) infection in patients with polyarteritis nodosa (PAN). Eleven patients with PAN were screened for the presence of CMV-DNA in their blood using the polymerase chain reaction (PCR). Serum anti-CMV IgG and anti-CMV IgM antibodies were determined by enzyme-linked immunosorbent assays (ELISA). The ELISA for IgM was negative in all cases whereas that for IgG was positive in eight cases. Only one patient was positive for CMV-DNA by PCR. He presented with myalgia, polyarthralgia, fever and weight loss, suggesting PAN activity. CMV infection was uncommon in our series of patients with PAN, despite disease activity and immunosuppressor therapy. The finding of a transient CMV infection in one case at the beginning of PAN activity suggests that CMV may be involved in the pathogenesis of PAN.

Serological profiles and evaluation of parasitaemia by PCR and blood culture in individuals chronically infected by Trypanosoma cruzi treated with benzonidazole

Objective  To evaluate the serological and parasitological status of patients with chronic Chagas disease (CD) after chemotherapy with benzonidazole.

Simultaneous monitoring of CMV and human herpesvirus 6 infections and diseases in liver transplant patients: one-year follow-up

OBJECTIVE: The aim of this study was to simultaneously monitoring cytomegalovirus and human herpesvirus 6 active infections using nested-polymerase chain reaction and, together with clinical findings, follow the clinical status of patients undergoing liver transplant. INTRODUCTION: The human β-herpesviruses, including cytomegalovirus and human herpesvirus 6, are ubiquitous among human populations. Active infections of human herpesvirus 6 and cytomegalovirus are common after liver transplantation, possibly induced and facilitated by allograft rejection and immunosuppressive therapy. Both viruses affect the success of the transplant procedure. METHODS: Thirty patients submitted to liver transplant at the Liver Transplant Unit, at the Gastro Center, State University of Campinas, SP, Brazil, were studied prospectively from six months to one year, nested-polymerase chain reaction for cytomegalovirus and human herpesvirus 6 DNA detections. Two or more consecutive positive nested-polymerase chain reaction were considered indicative of active infection. RESULTS: Active infection by cytomegalovirus was detected in 13/30 (43.3%) patients, median time to first cytomegalovirus detection was 29 days after transplantation (range: 0-99 days). Active infection by human herpesvirus 6 was detected in 12/30 (40%) patients, median time to first human herpesvirus 6 detection was 23.5 days after transplantation (range: 0-273 days). The time-related appearance of each virus was not statistically different (p = 0.49). Rejection of the transplanted liver was observed in 16.7% (5/30) of the patients. The present analysis showed that human herpesvirus 6 and/or cytomegalovirus active infections were frequent in liver transplant recipients at our center. CONCLUSIONS: Few patients remain free of betaherpesviruses after liver transplantation. Most patients presenting active infection with more than one virus were infected sequentially and not concurrently. Nested-polymerase chain reaction can be considered of limited value for clinically monitoring cytomegalovirus and human herpesvirus 6.

Cytomegalovirus (CMV) genotype in allogeneic hematopoietic stem cell transplantation

BackgroundBased on sequence variation in the UL55 gene that encodes glycoprotein B (gB), human cytomegalovirus (CMV) can be classified into four gB genotypes. Previous studies have suggested an association between CMV gB genotype and clinical outcome in patients who underwent an allogeneic hematopoietic stem cell transplant (HSCT). The goals of this study were identify patients with active infection caused by CMV in recipients of HSCT; determine the prevalence of CMV genotypes in the study group; correlate genotype with CMV disease, acute GVHD and overall survival.MethodsThe diagnosis of active CMV infection after allogeneic HSCT was detected by antigenemia (AGM) and/or nested-PCR (N-PCR). Positive samples from patients with active CMV infection were submitted to genotyping using N-PCR to amplify a region of UL55, followed by restriction analysis based on HinfI and RsaI digestion. Real-time PCR (qPCR) was used to determine the viral load during active CMV infection and antiviral treatment.ResultsSixty-three allogeneic HSCT recipients were prospectively evaluated; 49/63 (78%) patients were infected with CMV genotypes – gB1 19/49 (39%), gB2 17/49 (35%), gB3 3/49 (6%), gB4 7/49 (14%) – and 3 (6%) had mixed CMV genotypes (gB1 + gB3, gB1 + gB4 and gB2 + gB4). Characterized by gastrointestinal disease, CMV disease occurred in 3/49 (6.1%) patients, who had CMV gB3 genotype. These gB3 genotype patients presented an increasing AGM number, mean 125 (± 250) (P = 0.70), and qPCR copies/ml, mean 37938 (SD ± 50542) (P = 0.03), during antiviral treatment, when compared with other CMV genotypes. According to CMV genotypes, stratified overall survival was 55% for gB1, 43% for gB2; 0% for gB3 and 57% for gB4 (P = 0.03).ConclusionsOne of the restrictions of the presented study was the low number of CMV gB sub-cohorts). However, we demonstrated that the frequency of active CMV infection in this HSCT population was high, and the most prevalent genotype in these patients with active CMV infection was gB1 and gB2 genotype (74%). In Brazil, HSCT recipients seem to carry mainly gB1 and gB2 CMV genotype.

Human herpesvirus 6 in donor biopsies associated with the incidence of clinical cytomegalovirus disease and hepatitis C virus recurrence.

BACKGROUND Reactivation of cytomegalovirus (CMV) and human herpesvirus 6 (HHV-6), as well as the recurrence of hepatitis C virus (HCV), occurs in the post liver transplantation period. However, their correlations remain questionable. The objectives of this study were to analyze the presence of CMV DNA and HHV-6 DNA in pre-transplant and post-transplant liver graft biopsies and to determine any correlations with CMV disease and HCV recurrence. METHODS Forty-one liver transplant recipients were followed up in the post-transplant period. The presence of CMV DNA and HHV-6 DNA was detected by nested PCR. RESULTS Four patients (4/41, 9.8%) were positive for CMV DNA in pre-transplant biopsies and three of them remained positive after transplantation; 11 patients became positive in the post-transplant biopsies (p=0.06). Fifteen (15/41, 36.6%) patients were positive for HHV-6 DNA in pre-transplant biopsies and 11 of these remained positive after transplantation. Another 11 patients became positive after the surgery (p=0.05). CMV disease occurred in 17 recipients; 10 of these 17 (58.8%) patients were positive for HHV-6 DNA in pre-transplant biopsies and they continued positive after transplantation (p=0.0128). Twenty-eight patients were transplanted due to hepatitis C; 12 of these patients had recurrence of the virus, and HHV-6 was positive in nine of the 12 (75%) patients (p=0.049). CONCLUSIONS Recipients with HHV-6 DNA in pre-transplant graft biopsies remained positive post transplantation, showing a possible risk for post-transplant allograft loss because there was an association between HHV-6 and recurrent HCV and CMV disease.

Cytomegalovirus, Human Herpesvirus-6, and Human Herpesvirus-7 in Adult Liver Transplant Recipients: Diagnosis Based on Antigenemia

Human herpesvirus (HHV)-6, HHV-7, and cytomegalovirus (CMV) that remain latent after primary infection can be reactivated during immunosuppression following organ transplantation in liver transplant recipients. The aim of this study was to monitor active infections for HHV-6, HHV-7, and CMV among adult liver transplantation recipients using antigenemia detected by an immunoperoxidase staining. Twenty-eight adult liver transplant patients were monitored using antigenemia in blood samples obtained at the time of transplantation, as well as weekly in the first month and once a month for 6 months. Of these patients, 28.5% showed positive CMV antigenemia; 39.2%, HHV-6 antigenemia; and 14.2%, HHV-7 antigenemia. The detection of the three viruses was considered to be independent of one another (P>.05). The results described above showed that few patients remain free of beta herpesviruses after liver transplantation. Most patients were infected sequentially and not concurrently. Antigenemia has been considered useful to detect active HHV-6 and HHV-7 infections. Antigenemia can be more efficiently interpreted when compared with polymerase chain reaction results, although other studies are necessary to establish the reference of HHV-6 and HHV-7 antigenemia.