Respuesta de la terapia antirretroviral en niños con infección por VIH-1. Corte Transversal / Response of antiretroviral therapy in children with HIV-1 infection. Cross-cutting

En el 2003 se inició el Tratamiento Antirretrov iral de Gran Act ividad (TARGA) por parte de la Secretaria de Salud de nuestro país. El seguimiento de estos pacientes se hac ía clí nicamente y con exámenes de laboratorio como hemograma y quím ica Sanginea, del conteo de CD4 se inicio en el 2005 al igual que la carga viral (CV), esta ultima de modo muy irregular. Neuroestudio, inicia en el 2009 con la disponibilidad permanebte de exámenes de CD4 y CV. Nuestro objetivo fueron identificar las respuestas terapeutica de los niños(a) con infección del VIH-1 tratado en el Centro de atención integral del Hospital Nacional del Dr. Mario Catarino Rivas entre el 2009 y el 2011; realizando un análisis descriptivo de la situación clínica, inmunológica y virológica de los niños(as) en tratamiento antirretroviral. utilizamos la Clasificación de CDC para la valoración clínica e inmunológica. Consideramos no detectable la CV que es menor de 50 copias/mi a los 6 meses de iniciado el tratatamiento antirretroviral por el método aplificación por RT-PCR (Abbott Real Time m2000rt). Se analizaron 338 expedientes, encontrando una eficacia terapéutica total del 80.2%. El esquema terapeutico de segunda línea sin falla terapéutica. La causa mas frecuente de falla fue la mala adherencia en un 73.9% y por resistenci a en un 10.1%. En conclusión la adherenci a es un factor importante para mantener la eficac ia terapéutica, aunque en nuestr o estudio no resultó estadísticamente significativo...(AU)

Characterization of new monoclonal antibodies that discriminate between soluble and membrane CD4 and compete with human anti-CD4 autoimmune sera.

In this report we present results on immunization of hu-CD4 C57Black/6J transgenic mice with HIV-1 gp120(451) complexed with its receptor protein, CD4. In addition to development of anti-gp120 antibodies, these mice also produced two anti-CD4 monoclonal antibodies, designated T6 and T9. Both these antibodies recognize soluble CD4 but not membrane associated CD4. Their corresponding epitopes map to the D3-D4 domains of CD4. These characteristics are very similar to the HIV related anti-CD4 autoimmunity found in 10-15% of HIV-1 infected people. Therefore, 208 HIV-1 positive patients were screened for anti-CD4 humoral response of which 27 were found positive (13%). Sixteen of these patients were then tested for their ability to compete with the T6 and T9 anti-CD4 monoclonal antibodies. In such experiments saturating amounts of either T6 or T9 antibodies were able to prevent 20-80% of the human serum binding to immobilized soluble CD4 in competitive ELISA tests. The T6 and T9 antibodies therefore help to define distinct CD4 epitopes associated with clinical anti-CD4 autoimmunity.

A new isolation method for rat intraepithelial lymphocytes.

Intraepithelial lymphocytes (IELs) play critical roles in gut immunity. In mice, gammadelta T cells are a large component of the IEL population. In the rat, gammadelta IELs are reportedly much less common, but technical issues suggest that previous analyses should be interpreted cautiously. The study of IELs in rats has been impeded by isolation procedures that are lengthy and complex, leading to small cell yields. For this reason, it is possible that rat IELs analyzed in previous studies have not been representative of the entire IEL compartment. We report a new method for the isolation of rat IELs that is based on the selective removal of intestinal epithelial cells under conditions that leave the basement membrane undisturbed. The method is rapid and requires neither enzymatic digestion, nor surgical removal of Peyer's patches, nor vigorous mechanical manipulation of the intestine. The yield of rat IELs using this method is 5- to 10-fold greater than that reported for other methods. Morphological and phenotypic analyses demonstrated that the purified cell population is comprised of IELs and is not contaminated with lamina propria or Peyer's patch lymphocytes. Phenotypic analysis revealed five major subsets of IELs based on differential cell surface expression of CD4, CD8, and alphabeta T cell receptor (TcR). Among the alphabetaTcR- cells was a population of gammadelta T cells present at levels not previously detected. The isolation of IEL sub-populations using this methodology should facilitate studies of the function of these cells in gut immunity.

The nature of membrane anchorage determines kinase association and detergent solubility of CD4.

The presence of a glycosylphosphatidylinositol (GPI) anchor on a membrane protein is thought to influence aspects of the protein's biochemistry. While it has been demonstrated that a GPI-anchor is sufficient for altering the detergent solubility of integral membrane proteins, it has not been shown that the anchor is sufficient for changing the phosphoprotein associations of membrane proteins. In order to define the influence of GPI-anchors on the biochemistry of membrane proteins we compared the phosphoprotein associations and detergent solubility of wild-type and GPI-anchored CD4 expressed on HSB cell transfectants. While wild-type CD4 was mostly associated with lck kinase, GPI-anchored CD4 was associated with the 'GPI-anchored pattern of phosphoproteins'. The Triton X-100 solubilities of the two forms of CD4 were also distinct: wild-type CD4 was > 95% soluble, whereas GPI-anchored CD4 was only 65% soluble. These results underscore the deterministic role of the GPI-anchor in the properties associated with GPI-anchored proteins.

Identification of the T cell antigen receptor V beta gene products in labial salivary glands from patients with primary Sjögren's syndrome.

T lymphocytes are predominantly involved in the development of Sjögren's syndrome. Their repertoire has recently been claimed to be restricted. Analysis of T cell receptor V beta gene products within the labial salivary glands led us to identify V beta 2 and V beta 8. This study, using a new panel of anti-V beta product monoclonal antibodies and a tissue triple-staining technique, examined the distribution of V beta gene family products in activated as well as non-activated CD4+ or CD8+ T cells subsets in the salivary gland tissue of SS patients. Our results suggest that the V beta genes used by the T CD4+ or T CD8+ cells in situ are similar, irrespective of the activation status of these cells. T lymphocytes homing into exocrine tissues might thus be selected on the basis of their V beta repertoire rather than their activation state.

Induction of transplantation tolerance in adults using donor antigen and anti-CD4 monoclonal antibody.

The T-cell-mediated immune response usually results in the rapid destruction of organ allografts transplanted between murine strains incompatible for major and minor histocompatibility antigens. This response may be modified by pretreatment with either donor-specific antigen or anti-CD4 monoclonal antibody. Previous work by others has shown that combined treatment of mice with soluble protein antigens and anti-CD4 monoclonal antibody can produce antigen-specific B cell unresponsiveness that continues long after the nonspecific immunosuppressive effect of the mAb treatment has resolved. Following this principle we have shown that adult C3H/He mice can be made specifically unresponsive to vascularized C57BL/10 cardiac allografts by pretreating the recipient with donor alloantigen under the cover of a brief course of mAb against CD4. A full-dose response analysis shows that the dose of mAb is critically important for the successful induction of tolerance. Tolerance induction using this protocol is dependent on treatment with donor major histocompatibility complex antigens and occurs in the presence of marked depletion but not complete elimination of the CD4+ T cell subset. The unresponsiveness to alloantigen is antigen specific, as determined by the ineffectiveness of third-party (C57BL/10) alloantigen when combined with anti-CD4 mAb to induce long-term survival of BALB/c allografts in C3H/He recipients. The tolerant state is specific and effective in the long-term as indicated by the specific acceptance of C57BL/10 skin grafts in recipients with surviving C57BL/10 cardiac allografts. This study provides a simple method for the successful induction of specific transplantation tolerance in the adult across a full H-2 major and minor antigen mismatch strain combination. The results illustrate the important role of the CD4 molecule in the T cell response to alloantigen in vivo and suggest possibilities for the therapeutic manipulation of complex immune reactions.

Current treatment for human immunodeficiency virus infection.

Treatment of human immunodeficiency virus (HIV) infection can prolong survival and enhance the quality of life in affected patients, although neither immune reconstitution nor cure can be achieved. Zidovudine is now the only licensed treatment. It is effective but sometimes toxic. Zidovudine decreases the incidence of opportunistic infections but does not prevent them, and concurrent prophylaxis against Pneumocystis carinii pneumonia should be given to those patients at greatest risk of this infection. Most patients should have serial CD4+ T-cell determinations to assess their degree of immunodeficiency. Many investigational anti-HIV agents are being studied, and future treatments are likely to use multiple agents in combination or in sequence over many years.