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L F Brígido

Publications and source records attributed to L F Brígido.

6 recordsLinked to original sources
PubMed2000

HIV-1 diversity in Brazil: genetic, biologic, and immunologic characterization of HIV-1 strains in three potential HIV vaccine evaluation sites. Brazilian Network for HIV Isolation and Characterization.

The Brazilian Network for HIV Isolation and Characterization was established for the surveillance of HIV variability in Brazil. Here, we report characterization of HIV strains and virus-specific immune responses from 35 clinical samples collected from three potential HIV vaccine sites. Three genetic subtypes of HIV-1 were identified by heteroduplex mobility assay (HMA) B (in 82.9% of the samples), F (14.3%), and C (2.9%). Phylogenetic analysis based on the C2V3/env DNA sequence from all 25 specimens examined was 100% concordant with HMA results. Four variants of subtype B with different tetrapeptides at the tip of the V3 loop were found: the GPGR motif (North American), GWGR motif (Brazilian B"), and two minor variants, GFGR and GPGS, as previously detected. No significant association was found between HIV-1 subtypes and the mode of transmission or biologic properties of HIV-1 isolates (derived from 88.6% of the specimens). Only 5 of 16 isolates studied were neutralized by the autologous sera. Consistent with previous results, no relation between viral subtype and peptide enzyme-linked immunosorbent assay (ELISA) seroreactivity or neutralization was evident. This study also demonstrated the effectiveness of the collaborative approach followed by Brazilian scientists when addressing a complex subject such as HIV variability.

AIDS Vaccines↗
PubMed1998

Two variants of HIV-1 B serotype are transmitted heterosexually in São Paulo, Brazil.

HIV-1 variability may have an important impact on transmission and pathogenicity. Better characterization of the HIV epidemic in Brazil is necessary for the development of vaccine trials in this country. We analyzed sera from 108 HIV-1-infected volunteers from São Paulo City to determine serotype and reactivity for V3 motifs of HIV in this population, and the relationship to transmission mode. We concluded that the HIV-1 B serotype is frequent among heterosexually infected women, even in the absence of anal sex, and that two major V3 motifs, GPGR and GWGR, had similar prevalence among women (48% and 52%, respectively) and men (56% and 44%, respectively). We also observed an equal distribution of these strains regardless of their CD4+ T cell counts, clinical status, and mode of transmission. Even though V3 serology for HIV-1 subtyping is an inexpensive tool for use in developing countries, additional methods, such as heteroduplex mobility assay and direct DNA sequencing, should be included to determine HIV-1 genetic diversity.

Adult↗
PubMedDate not supplied

[Common variable immunodeficiency (hypogammaglobulinemia of late onset or acquired hypogammaglobulinemia): initial follow-up of 11 cases].

The present paper describes the clinical and laboratory follow-up of 11 patients with the diagnosis of common variable immunodeficiency. Their age varied from 8 to 45 years. The mean disease time was 12.6 years and mean diagnosis time 4.3 years. Infectious manifestations, mainly of the respiratory and digestive tracts, occurred in all patients. Polyadenomegaly was noted in seven, hepatomegaly in six, splenomegaly in five and arthralgia in four patients. All of them presented serum IgG less than 250 mg/dl. IgA less than 33 mg/dl and IgM less than 31 mg/dl, except one with IgM = 176 mg/dl. The isohaemagglutinin titers were less than 1/20 in all but one patient. The determination of the number of B lymphocytes in the peripheral blood revealed normal counts in three, elevated in one and decreased in five patients. The CD-4/CD-8 ratio was less than 1 in 8 and greater than 1 in three of them. Five patients had positive cutaneous late reactions to at least one of the following antigens: PPD, SK-SD (Varidase), Trichophytin and Levedurin (Candidin). A decrease of the proliferative activity of peripheral blood mononuclear cells stimulated by lectins (PHA, Con-A, PWM) was also noted. Natural killer function was decreased. The association a possible role of regulatory lymphocytes in the immunopathogenesis of this disease. The data presented here emphasize the diversity of clinical and immunological manifestations of this disease, which could be noted between diverse patients and in the follow-up of a single one. In our cases the disease had an evolutive character, with a primarily humoral dysfunction followed by cellular immunity disturbances that determined poorer prognosis and progressive difficulties in the therapeutics. We suggest a conceptual reevaluation of this condition and a new denomination, for instance "Late-Onset Combined Immunodeficiency". The long delay between the initial clinical manifestations of the disease and its diagnosis was a handicap for an adequate treatment. Early intervention could certainly decrease the morbidity and mortality of the disease.

Adolescent↗
PubMedDate not supplied

[Immunologic changes associated with human immunodeficiency virus (HIV)].

Infection by HIV usually leads to dysfunction of the immune system which, facilitates the development of opportunistic infections or neoplasia in which almost always are fatal. The pathological process associated with this infection involves, characteristically, the destruction or malfunction of helper T lymphocytes (CD4+), due to, besides other factors, direct parasitism of the virus or to the secondary immune response, which seems to include autoimmune mechanisms. These pathological changes, along with the action of the virus on other components of the immune system, disturb the production of trophic factors and also the proliferation, differentiation and effector ability of different cells of the immune system. The long latent period, when a large number of infected individuals remain asymptomatic or with only minor clinical and/or laboratory disturbances suggest the possible role of some as yet uncharacterized cofactors, either inherent to the host or to other environmental agents; these cofactors may play a role in the modulation of the progression to this syndrome (AIDS).

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

The value of the lymphocyte proliferation test with phytohemagglutinin in the immune evaluation of Brazilian HIV-infected patients.

We evaluated phytohemagglutinin (PHA) lymphocyte proliferation and delayed-type hypersensitivity tests in 130 Brazilian HIV-infected patients with the objective of assessing the value of these tests in staging HIV infection. Patients were divided into three groups according to their CD4+ cell counts (cells/mm3): < 200 (n = 28); 200 to 499 (n = 50); and > or = 500 (n = 52). An additional 114 individuals, who had come to the same institution for elective surgeries, were enrolled as controls. Results showed a significant decrease in PHA responses when CD4+ cell counts fell below 500 cells/mm3. This decrease was, however, indistinguishable from that of patients with < 200 cells/mm3. In contrast, skin test anergy to common antigenic preparations was only evident in the group of patients with less than 200 CD4+ cells/mm3. Decreases in PHA responses and in CD4+ cell counts were significantly correlated. Since the introduction of antiretroviral therapy is recommended when CD4+ cell counts are below 500 cells/mm3, the PHA proliferation test, in our conditions, could be useful as an additional parameter to initiate antiretroviral therapy. Further prospective studies are needed to establish the value of this test in HIV-infected patients.

Adult↗