Non-detection of human herpesvirus 8 (HHV-8) DNA in HHV-8-seropositive blood donors from three Brazilian regions.

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the etiologic agent of all forms of Kaposi's sarcoma, primary effusion lymphoma and the plasmablastic cell variant of multicentric Castleman disease. In endemic areas of sub-Saharan Africa, blood transfusions have been associated with a substantial risk of HHV-8 transmission. By contrast, several studies among healthy blood donors from North America have failed to detect HHV-8 DNA in samples of seropositive individuals.

Seroreactivity to Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) latent nuclear antigen in AIDS-associated Kaposi's sarcoma patients depends on CD4+ T-cell count.

In AIDS/Kaposi's sarcoma (KS) patients, the sensitivity of immunofluorescence assays for detecting antibodies against latent nuclear antigen ranges from 52% to 93%. However, in classic and African KS, sensitivities above 90% have been reported systematically. This study evaluates whether CD4+ T-cell count affects seroreactivity to KSHV LANA and to lytic antigens in AIDS/KS patients.

Human herpesvirus-8 infection and oral shedding in Amerindian and non-Amerindian populations in the Brazilian Amazon region.

Background: Human herpesvirus type 8 (HHV-8) is hyperendemic in Amerindian populations, but its modes of transmission are unknown.

Methods: Antibodies against either HHV-8 lytic antigen or HHV-8 latency-associated nuclear antigen (LANA) were detected, by immunofluorescence assays, in 339 Amerindians and 181 non-Amerindians from the Brazilian Amazon. Serological markers of oro-fecal (hepatitis A), parenteral (hepatitis B and C), and sexual (herpes simplex virus type 2 and syphilis) transmission were measured by specific ELISAs.

Sensitivity and specificity of three ELISA-based assays for discriminating primary from secondary acute dengue virus infection.

Background: Discrimination between primary and secondary dengue virus infection traditionally has been performed using the hemagglutination inhibition (HI) test. However, this test has practical limitations and disadvantages.

Objective: To evaluate the ability of three ELISA-based methods (IgG avidity test, IgM/IgG ratio and IgG titer) to discriminate primary from secondary dengue infection.

Evaluation of a commercial real-time PCR kit for detection of dengue virus in samples collected during an outbreak in Goiania, Central Brazil, in 2005.

In the past 2 decades, dengue has reemerged in Brazil as a significant public health problem. Clinicians demand a diagnostic test with high sensitivity that is applicable during the early symptomatic phase. We aimed to test two distinct molecular methods on samples from suspected dengue cases during an outbreak in Central Brazil.

Seroprevalence of antibodies against varicella-zoster virus and response to the varicella vaccine in pediatric renal transplant patients.

The severity of varicella-zoster virus (VZV) in immunocompromised children, especially in those receiving renal transplants, is well known. However, the use of live attenuated virus vaccine in this population is controversial. This study aimed to: (i) assess the immunization status of pediatric renal transplant recipients at our center; (ii) determine the anti-VZV antibody titers in such patients; (iii) evaluate the response to VZV vaccine in seronegative children and in those who present low antibody titers (defined as <500 mAU/mL).

Human herpesvirus 8 (HHV-8) infection in HIV/AIDS patients from Santos, Brazil: seroprevalence and associated factors.

Goal: The goal of this study was to evaluate the seroprevalence of human herpesvirus 8 (HHV-8) infection among HIV-infected individuals from Brazil and the associated risk factors.

Study: A cross-sectional survey was carried out with 497 HIV/AIDS outpatients attending the local AIDS Reference Center in Santos (southeastern Brazil) between February 1997 and January 1998 had serum samples screened for anti-HHV-8 antibodies. Patients were considered seropositive whenever reactivity was observed in at least 1 of 3 tests (immunofluorescence assays for latent nuclear and lytic antigens and orf65 recombinant antigen enzyme-linked immunosorbent assay).

Use of an immunoglobulin G avidity test to discriminate between primary and secondary dengue virus infections.

An enzyme-linked immunosorbent assay-based immunoglobulin G (IgG) antibody avidity test was evaluated by using sera from 57 patients with acute dengue infection. Overall, 55 of 57 patients were correctly classified (27 of 27 with primary dengue and 28 of 30 with secondary dengue). We conclude that the IgG avidity test can be useful for differentiating between acute, primary, and secondary dengue infections.

Identification of primary and secondary measles vaccine failures by measurement of immunoglobulin G avidity in measles cases during the 1997 São Paulo epidemic.

Despite almost universal use of measles vaccines in recent decades, epidemics of the disease continue to occur. Understanding the role of primary vaccine failure (failure to seroconvert after vaccination) and secondary vaccine failures (waning immunity after seroconversion) in measles epidemics is important for the evaluation of measles control programs in developing countries. After a measles epidemic in São Paulo, Brazil, 159 cases previously confirmed by detection of specific immunoglobulin M (IgM) antibodies were tested for IgG avidity, and a secondary immune response, defined by an IgG avidity index of at least 30%, was established in 30 of 159 (18.

2-Chloro-deoxyadenosine induces durable complete remission in Castleman's disease but may accelerate its transformation to non-Hodgkin's lymphoma.

There is currently no consensus on the best treatment for unresectable hyaline-vascular variant or for multicentric Castleman's disease (MCD), because none of the reported regimens have consistently produced complete response or durable remission in the majority of patients In the present study, we report on the use of 2-CdA (2-chloro-deoxyadenosine) in three patients, two of them with MCD and one with unresectable hyaline-vascular type disease. Relapse-free survival of the responding patients was 24 and 20 months. Later, both patients evolved to non-Hodgkin's lymphoma (NHL) (diffuse large B-cell lymphoma and peripheral T-cell NHL, respectively).

Cytomegalovirus glycoprotein B genotypes and central nervous system disease in AIDS patients.

To investigate any association between cytomegalovirus glycoprotein B (CMV gB) subtypes and central nervous system (CNS) disease in AIDS patients, proportions of different gB genotypes detected in AIDS patients with CNS disease were compared with the gB genotypes detected in AIDS patients with no neurological disorder. The patients were matched by CD4+ cell counts. CMV was detected by PCR in cerebrospinal fluid (CSF) samples obtained from AIDS patients with CNS disease and from urine and saliva samples obtained from AIDS patients without CNS disease.

[Prevalence of varicella-zoster virus antibodies in young adults from different Brazilian climatic regions].

To evaluate the prevalence of varicella-zoster virus infection in young adults from different Brazilian urban regions, 975 serum samples from blood donors aged 20 to 29 years, from tropical climate cities (Salvador and Fortaleza) and from temperate climate cities (S o Paulo, Curitiba and Porto Alegre) were tested by an in-house ELISA for detection of anti-varicella-zoster virus IgG antibodies. The overall prevalence was 94.2%.

Measles in bone marrow transplant recipients during an outbreak in São Paulo, Brazil.

In 1997, a measles outbreak was identified in São Paulo. Between February and December, 20 185 cases were confirmed. From April to July 1997, a seroepidemiologic survey was conducted to identify the recipients of bone marrow (BM) transplants who were susceptible to measles and the occurrence of measles in this population.