Humoral response to the BBIBP-CorV vaccine over time in healthcare workers with or without exposure to SARS-CoV-2.

SARS-CoV-2-specific humoral response was analyzed over time in a group of healthcare workers with or without exposure to SARS-CoV-2, who underwent vaccination with BBIBP-CorV (Sinopharm) vaccine in Argentina. Seroconversion rates in unexposed subjects after the first and second doses were 40 % and 100 %, respectively, showing a significant increase in antibody concentrations from dose 1 to dose 2 (p < 0.0001). The highest antibody concentrations were found in younger subjects and women, remaining significantly associated in a multivariable linear regression model (p = 0.005). A single dose of the BBIBP-CorV vaccine induced a strong antibody response in individuals with prior SARS-CoV-2infection, while a second dose did not increase this response. A sharp increase in antibody concentrations was observed following SARS-CoV-2 infection in those participants who became infected after the first and second doses (p = 0.008). Individuals with SARS-CoV-2 exposure prior to vaccination showed significantly higher anti-spike IgG antibody levels, at all-time points, than those not exposed (p < 0.001). Higher antibody titers were induced by a single dose in previously SARS-CoV-2 infected individuals than those induced in naïve subjects by two doses of the vaccine (p < 0.0001). Three months after the second dose both groups showed a decline in antibody levels, being more abrupt in unexposed subjects. Overall, our results showed a trend towards lower antibody concentrations over time following BBIBP-CorV vaccination. Sex and age seem to influence the magnitude of the humoral response in unexposed subjects while the combination of exposure to SARS-CoV-2 plus vaccination, whatever the sequence of the events was, produced a sharp increase in antibody levels. Evaluation of the humoral responses over time and the analysis of the induction and persistence of memory B and T cell responses, are needed to assess long-term immune protection induced by BBIBP-CorV vaccine.

Influence of Hepatitis C virus coinfection on immune reconstitution in HIV subjects.

Despite successful HIV suppression by antiretroviral treatment (ART), immune activation may persist in HIV patients, contributing to an impaired immunological reconstitution and disease progression. Information regarding Hepatitis C virus (HCV) coinfection as a factor that accounts for immune activation in HIV subjects remains unclear. Furthermore, most studies have been carried out considering HIV/HCV patients as a whole, without taking into account the presence or absence of liver damage. Therefore, it is unknown if HCV and/or its liver-related disease could act as two independent factors contributing to the immune activation. In this study, we investigated the presence of immune activation in a cohort of 50 HIV/HCV patients by measuring cytokine levels, CD4+ T-cell counts and CD4/CD8 ratios. Six patient groups were defined according to HIV viral load, HCV status, and liver disease to assess the impact of each of these factors on immune activation and reconstitution in HIV/HCV patients. Only subjects with controlled HIV infection and cleared HCV displayed immunological parameters within normal ranges. The mere presence of HCV contributes to immune activation leading to an inappropriate immunological reconstitution. This state exacerbates in the presence of HCV-associated liver disease. Our results suggest that ART is not enough to suppress immune activation in the context of HIV/HCV coinfection, since both HCV and its liver-related disease would contribute to the immune activation. Given that immune activation worsens immunological reconstitution and clinical status, these results support the priority of HCV treatment in HIV/HCV patients and suggest the monitoring of their liver status.

Christiane Dosne de Pasqualini, su trayectoria personal y científica / Christiane Dosne de Pasqualini his personal and scientific career

Christian Dosne de Pasqualini es una figura importante de la investigación científica en la Argentina dentro del área de la oncología experimental y de la inmunología. Nacida en las cercanías de Paris en 1920, creció en el Canada, estudió en la Universidad McGill y realizó su tesis doctoral con el Dr Hans Selye, investigador que describió el fenómeno de "stress" en Biología. Llegó a la Argentina en 1942 atraída por su deseo de trabajar con el Profesor Bernardo Houssay. En la Argentina desarrolló una importante tarea de investigación dentro de la Academia de Medicina y del CONICET. Este trabajo presenta una visión personal y quizás sesgada sobre su trayectoria. Se analiza el impacto del recorrido personal y científico de esta extraordinaria mujer sobre generaciones de jóvenes investigadores

Christiane Dosne Pasqualini is a key player in the development of scientific research In Argentina. Her field of study covers experimental oncology and immunology. She was born in Saint Denis, near Paris, France in 1920. She grew up in Canada, went to college in McGill University and got her doctoral degree under the direction of Dr Hans Selye, who described the characteristics of "stress". As a research fellow, she set foot in Argentina in 1942, attracted by a publication of Dr Bernardo Houssay. In Argentina she performed her research work in the laboratories of the National Academy of Medicine (Academia Nacional de Medicina) as a member of the National Council of Scientific and Technical Research (CONICET). The present article represents my personal and perhaps biased vision of her life story. The impact of the personal and scientific achievements of this extraordinary woman on many generations of investigators is analyzed.

Anticuerpos anti-FVIII: su evaluación por citometría de flujo / Anti FVIII antibodies: evaluation by flow cytometry

En este trabajo se describe un sistema para evaluar y caracterizar los anticuerpos anti-FVIII en pacientes con Hemofilia A Severa (HAS) que reciben el Factor como tratamiento de sustitución. Consiste en el empleo combinado de microesferas y Citometria de Flujo (CF). El rFVIII fue acoplado a microesferas de 2 µm de diámetro (m-FVIII) las cuales se incubaron con diluciones de plasma o suero de pacientes con (n=13) o sin (n=17) inhibidor, pacientes en Tratamiento Inmunotolerante (TIT)(n=5) y dadores normales (N) (n=12). Los anticuerpos se revelaron con anti-lgG humana, anti-lgG1, anti-lgG2, anti-IgG3 o anti-lgG4 biotiniladas, seguido por streptavidina-ficoeritrina. Se registraron los valores de Intensidad de Fluorescencia Media (IFM). Microesferas sin FVIII (m-Control) se utilizaron como control. El resultado se expresó como índice: (IFM de m-FVIII/IFM de m-Control) multiplicado por la inversa de la dilución de máxima respuesta. Se determinó el porcentaje de contribución de cada subclase de IgG. Los resultados presentaron un 86 por ciento de concordancia con la prueba de Bethesda y un 80 por ciento con ELISA. El método fue útil para el seguimiento de los pacientes durante el TIT. La IgG4 prevaleció en pacientes con alto título y al comienzo del TIT. La CF es fácil y rápida y requiere sólo 200 µl de muestra.

In this study, a Flow Cytometry (FC) system is described for detecting and characterizing antibodies (inhibitors) to Factor VIII (FVIII) in Severe Haemophilia A (SHA) patients following FVIII infusion. A combination of microspheres and Flow Cytometry (FC) was employed. First, rFVIII was coupled to microspheres of 2 µm of diameter (m-FVIII). Then, they were reacted with dilutions of plasma or serum of patients with (n=13) or without (n=17) inhibitors. Five patients receiving Immunotolerant Treatment (ITI) and 12 normal donors were included. Microspheres without rFVIII were used as control (m-Control). Captured anti-FVIII antibodies were detected using biotinylated anti-Human IgG, IgG1, IgG2, IgG3 or IgG4 followed by streptavidin-phycoerythrin. FC analysis was performed recording Mean Fluorescence Intensity (MFI). Results were given as an Index: the highest MFI ratio between m-FVIII and m-Control multiplied by the inverse of the corresponding plasma dilution. The contribution of each IgG subclass was expressed as percentage. FC results had 86 per cent and 80 per cent of coincidence with the Bethesda method and ELISA respectively. The test was useful to measure anti-FVIII antibodies during the ITI. IgG4 was the prevalent IgG subclass in patients with high level of inhibitors and previously to ITI. FC was easy, fast and requires only 200 µl of sample.

Macrophage HIV-1 infection in duodenal tissue of patients on long term HAART.

Mucosal surfaces play a major role in human immunodeficiency virus type 1 (HIV-1) transmission and pathogenesis. Since the role of intestinal macrophages as viral reservoirs during chronic HIV-1 infection has not been elucidated, we investigated the effects of successful therapy on intestinal HIV-1 persistence. Intestinal macrophage infection was demonstrated by the expression of p24 antigen by flow cytometry and by the presence of proviral DNA, assessed by PCR. Proviral DNA was detected in duodenal mucosa of HIV-infected patients under treatment with undetectable plasma viral load. These findings confirm that intestinal macrophages can act as viral reservoirs and permit HIV-1 production even after viral suppression following antiretroviral therapy.

Cross-talk between CD31 and the signaling lymphocytic activation molecule-associated protein during interferon- gamma production against Mycobacterium tuberculosis.

Effective host defense against tuberculosis requires Th1 cytokine responses. We studied the regulation of interferon (IFN)- gamma production during tuberculosis by investigating the role of CD31, a receptor that attenuates T cell receptor signals. After antigen stimulation, CD3(+)CD31(+) blood lymphocytes decreased in healthy donors and in tuberculosis patients with robust Th1 responses to Mycobacterium tuberculosis and IFN- gamma was secreted only by CD31(-) T cells. In contrast, in patients with weak Th1 cytokine responses to M. tuberculosis, the level of CD3(+)CD31(+) lymphocytes was increased and IFN- gamma production was low. Furthermore, the inverse relationship between CD31 expression and IFN- gamma production was in contrast to signaling lymphocytic activation molecule (SLAM) expression, an IFN- gamma inducer in tuberculosis. Interestingly, CD31 bound to SLAM-associated protein (SAP), an IFN- gamma inhibitor in tuberculosis, and when CD31 and SAP were coexpressed in lymphocytes, their association inhibited the IFN- gamma response to M. tuberculosis. Thus, CD31, when binding to SAP, interferes with Th1 responses, suggesting that CD31 has a key regulatory role in the signaling pathway(s) leading to the IFN- gamma response to M. tuberculosis.

The intestinal mucosa as a reservoir of HIV-1 infection after successful HAART.

The presence of HIV-1 RNA in distal duodenal mucosa was evaluated in 44 HIV-1-positive patients. HIV-1 RNA was detected in gut tissue in antiretroviral-naive patients with high plasma viral loads, as well as in patients on HAART with plasma viral loads below the limit of detection and in patients on HAART with virological failure. The intestinal mucosa seems to serve as a reservoir poorly influenced by levels of plasma viral load or HAART.

[The role of dendritic cells in the infection by HIV and HCV]. / Papel de las celulas dendriticas en la infeccion por HIV y HCV.

Dendritic cells are most important as antigen presenting cells during the induction of an effective immune response. Therefore, it is important to study their role during the generation of persistent or chronic viral infections, such as HIV or HCV infection. In this review we shall describe the phenotypic and functional characteristics of the different classes of dendritic cells and of their membrane receptors. Their participation in defence or facilitation mechanisms involved in the immune response against these viruses will be discussed. It is important to take this knowledge into account when trying to design therapeutic strategies for protection or reconstruction of the immune system that may be altered as a consequence of infection with HIV or HCV.

Papel de las células dendríticas en la infección por HIV y HCV / The role of dendritic cells in the infection by HIV and HCV

Las células dendríticas son las principales células presentadoras de antígenos para el montaje de la respuesta inmune. Por lo tanto es importante estudiar de qué manera intervienen en el equilibrio que el sistema inmune desarrolla frente a infecciones virales persistentes como la infección por el HIV o el HCV. En esta revisión se presentan en primer término generalidades sobre las diferentes clases de células dendríticas, las características fenotípicas y funcionales que las definen y los receptores que pueden estar involucrados en la infección viral. Luego se analiza su participación en los mecanismos de defensa o facilitadores de la infección por estos virus. Es importante tener en cuenta estos conocimientos para poder diseñar adecuadas estrategias de vacunación o protección y para intentar la reconstrucción funcional del sistema inmune impidiendo la subversión de los mecanismos inmunes de defensa causada por la infección con el HIV y el HCV.(AU)

Dendritic cells are most important as antigen presenting cells during the induction of an effective immune response. Therefore, it is important to study their role during the generation of persistent or chronic viral infections, such as HIV or HCV infection. In this review we shall describe the phenotypic and functional characteristics of the different classes of dendritic cells and of their membrane receptors. Their participation in defence or facilitation mechanisms involved in the immune response against these viruses will be discussed. It is important to take this knowledge into account when trying to design therapeutic strategies for protection or reconstruction of the immune system that may be altered as a consequence of infection with HIV or HCV. (AU)

Papel de las células dendríticas en la infección por HIV y HCV / The role of dendritic cells in the infection by HIV and HCV

Las células dendríticas son las principales células presentadoras de antígenos para el montaje de la respuesta inmune. Por lo tanto es importante estudiar de qué manera intervienen en el equilibrio que el sistema inmune desarrolla frente a infecciones virales persistentes como la infección por el HIV o el HCV. En esta revisión se presentan en primer término generalidades sobre las diferentes clases de células dendríticas, las características fenotípicas y funcionales que las definen y los receptores que pueden estar involucrados en la infección viral. Luego se analiza su participación en los mecanismos de defensa o facilitadores de la infección por estos virus. Es importante tener en cuenta estos conocimientos para poder diseñar adecuadas estrategias de vacunación o protección y para intentar la reconstrucción funcional del sistema inmune impidiendo la subversión de los mecanismos inmunes de defensa causada por la infección con el HIV y el HCV.

Dendritic cells are most important as antigen presenting cells during the induction of an effective immune response. Therefore, it is important to study their role during the generation of persistent or chronic viral infections, such as HIV or HCV infection. In this review we shall describe the phenotypic and functional characteristics of the different classes of dendritic cells and of their membrane receptors. Their participation in defence or facilitation mechanisms involved in the immune response against these viruses will be discussed. It is important to take this knowledge into account when trying to design therapeutic strategies for protection or reconstruction of the immune system that may be altered as a consequence of infection with HIV or HCV.

[Chronic urticaria. Clinical evolution, autologous serum test, count and activation of basophils]. / Urticaria crónica. Evolución clínica, prueba del suero autólogo, recuento y activación de basófilos.

Recent advances on the pathogenesis of chronic urticaria have defined a group of patients with autoantibodies directed to the IgE or to the alpha chain of the Fc high affinity receptor of IgE, Fc epsilon RI alpha. These antibodies are detected in vivo through the autologous serum test (AST) and in vitro with a variety of techniques. We here describe 37 patients with chronic urticaria, 28 female and 9 male, with a f/m ratio of 3.1. Mean age at onset was 36.5 years (range 16-78). AST was positive in 25 (68%) of 37 patients. Serum induced a wheal significantly larger than plasma (122 +/- 78 mm2 vs 57 +/- 66 mm2, p < 0.05). Median persistence of the chronic urticaria, estimated by Kaplan-Meyer analysis, was 437 days, with no difference between AST(+) and AST(-) patients (437 vs. 369, p = 0.18). Mean IgE concentration was 157 +/- 173 IU/mL, as expected in an unselected population. Basophil count was lower in patients compared with controls (17 +/- 12 cel/microL vs. 43 +/- 27 cel/microL, p < 0.008). Only sera from 2/7 (28.6%) patients AST (+) and very low basophil count consistently induced expression of CD63. This effect was abrogated in non-releasing basophils, confirming the presence of antibodies directed to the Fc epsilon RI alpha-IgE. We conclude that functional antibodies are present in only a minority of patients and that their identification does not predict the outcome.

[X-linked lymphoproliferative syndrome, EBV virus infection and defects in cytotoxicity lymphocyte regulation]. / Sindrome linfoproliferativo ligado al cromosoma X, infección por el virus EBV y defectos en la regulación de la citotoxicidad linfocitaria.

Mutations in SH2D1A, a gene that codifies for the regulatory protein SAP, result in uncontrolled activation of the SLAM (signaling lymphocyte-activation molecule) pathway. This X-linked immunodeficiency becomes evident when the patients are infected with Epstein Barr virus (EBV) and develop a fulminant form of infectious mononucleosis leading to a lymphoproliferative syndrome that is often fatal (X-linked lymphoproliferative syndrome, XLP). In those who survive, hypogammaglobulinemia and oncohematologic diseases are frequently observed. In this revision, the immuno-regulatory mechanisms involved in XLP immunopathology and the role of different effector cells (CD8 T lymphocytes, NK cells) are discussed.

Urticaria cronica. Evolucion clinica, prueba del suero autologo, recuento y activacion de basofilos / Chronic urticaria. Clinical evolution, autologous serum test, count and activation of basophils

Recent advances on the pathogenesis of chronic urticaria have defined a group of patients with autoantibodies directed to the IgE or to the alpha chain of the Fc high affinity receptor of IgE, Fc epsilon RI alpha. These antibodies are detected in vivo through the autologous serum test (AST) and in vitro with a variety of techniques. We here describe 37 patients with chronic urticaria, 28 female and 9 male, with a f/m ratio of 3.1. Mean age at onset was 36.5 years (range 16-78). AST was positive in 25 (68%) of 37 patients. Serum induced a wheal significantly larger than plasma (122 +/- 78 mm2 vs 57 +/- 66 mm2, p < 0.05). Median persistence of the chronic urticaria, estimated by Kaplan-Meyer analysis, was 437 days, with no difference between AST(+) and AST(-) patients (437 vs. 369, p = 0.18). Mean IgE concentration was 157 +/- 173 IU/mL, as expected in an unselected population. Basophil count was lower in patients compared with controls (17 +/- 12 cel/microL vs. 43 +/- 27 cel/microL, p < 0.008). Only sera from 2/7 (28.6%) patients AST (+) and very low basophil count consistently induced expression of CD63. This effect was abrogated in non-releasing basophils, confirming the presence of antibodies directed to the Fc epsilon RI alpha-IgE. We conclude that functional antibodies are present in only a minority of patients and that their identification does not predict the outcome

Sindrome linfoproliferativo ligado al cromosoma X, infeccion por el virus EBV y defectos en la regulacion de la citotoxicidad linfocitaria / X-linked lymphoproliferative syndrome, EBV virus infection and defects in cytotoxicity lymphocyte regulation

Mutations in SH2D1A, a gene that codifies for the regulatory protein SAP, result in uncontrolled activation of the SLAM (signaling lymphocyte-activation molecule) pathway. This X-linked immunodeficiency becomes evident when the patients are infected with Epstein Barr virus (EBV) and develop a fulminant form of infectious mononucleosis leading to a lymphoproliferative syndrome that is often fatal (X-linked lymphoproliferative syndrome, XLP). In those who survive, hypogammaglobulinemia and oncohematologic diseases are frequently observed. In this revision, the immuno-regulatory mechanisms involved in XLP immunopathology and the role of different effector cells (CD8 T lymphocytes, NK cells) are discussed

Urticaria cronica. Evolucion clinica, prueba del suero autologo, recuento y activacion de basofilos / Chronic urticaria. Clinical evolution, autologous serum test, count and activation of basophils

Recent advances on the pathogenesis of chronic urticaria have defined a group of patients with autoantibodies directed to the IgE or to the alpha chain of the Fc high affinity receptor of IgE, Fc epsilon RI alpha. These antibodies are detected in vivo through the autologous serum test (AST) and in vitro with a variety of techniques. We here describe 37 patients with chronic urticaria, 28 female and 9 male, with a f/m ratio of 3.1. Mean age at onset was 36.5 years (range 16-78). AST was positive in 25 (68%) of 37 patients. Serum induced a wheal significantly larger than plasma (122 +/- 78 mm2 vs 57 +/- 66 mm2, p < 0.05). Median persistence of the chronic urticaria, estimated by Kaplan-Meyer analysis, was 437 days, with no difference between AST(+) and AST(-) patients (437 vs. 369, p = 0.18). Mean IgE concentration was 157 +/- 173 IU/mL, as expected in an unselected population. Basophil count was lower in patients compared with controls (17 +/- 12 cel/microL vs. 43 +/- 27 cel/microL, p < 0.008). Only sera from 2/7 (28.6%) patients AST (+) and very low basophil count consistently induced expression of CD63. This effect was abrogated in non-releasing basophils, confirming the presence of antibodies directed to the Fc epsilon RI alpha-IgE. We conclude that functional antibodies are present in only a minority of patients and that their identification does not predict the outcome (AU)

Sindrome linfoproliferativo ligado al cromosoma X, infeccion por el virus EBV y defectos en la regulacion de la citotoxicidad linfocitaria / X-linked lymphoproliferative syndrome, EBV virus infection and defects in cytotoxicity lymphocyte regulation

Mutations in SH2D1A, a gene that codifies for the regulatory protein SAP, result in uncontrolled activation of the SLAM (signaling lymphocyte-activation molecule) pathway. This X-linked immunodeficiency becomes evident when the patients are infected with Epstein Barr virus (EBV) and develop a fulminant form of infectious mononucleosis leading to a lymphoproliferative syndrome that is often fatal (X-linked lymphoproliferative syndrome, XLP). In those who survive, hypogammaglobulinemia and oncohematologic diseases are frequently observed. In this revision, the immuno-regulatory mechanisms involved in XLP immunopathology and the role of different effector cells (CD8 T lymphocytes, NK cells) are discussed (AU)

Urticaria crónica. Evolución clínica, prueba del suero autólogo, recuento y activación de basófilos. / [Chronic urticaria. Clinical evolution, autologous serum test, count and activation of basophils]

Recent advances on the pathogenesis of chronic urticaria have defined a group of patients with autoantibodies directed to the IgE or to the alpha chain of the Fc high affinity receptor of IgE, Fc epsilon RI alpha. These antibodies are detected in vivo through the autologous serum test (AST) and in vitro with a variety of techniques. We here describe 37 patients with chronic urticaria, 28 female and 9 male, with a f/m ratio of 3.1. Mean age at onset was 36.5 years (range 16-78). AST was positive in 25 (68

) of 37 patients. Serum induced a wheal significantly larger than plasma (122 +/- 78 mm2 vs 57 +/- 66 mm2, p < 0.05). Median persistence of the chronic urticaria, estimated by Kaplan-Meyer analysis, was 437 days, with no difference between AST(+) and AST(-) patients (437 vs. 369, p = 0.18). Mean IgE concentration was 157 +/- 173 IU/mL, as expected in an unselected population. Basophil count was lower in patients compared with controls (17 +/- 12 cel/microL vs. 43 +/- 27 cel/microL, p < 0.008). Only sera from 2/7 (28.6

) patients AST (+) and very low basophil count consistently induced expression of CD63. This effect was abrogated in non-releasing basophils, confirming the presence of antibodies directed to the Fc epsilon RI alpha-IgE. We conclude that functional antibodies are present in only a minority of patients and that their identification does not predict the outcome.

Sindrome linfoproliferativo ligado al cromosoma X, infección por el virus EBV y defectos en la regulación de la citotoxicidad linfocitaria. / [X-linked lymphoproliferative syndrome, EBV virus infection and defects in cytotoxicity lymphocyte regulation]

Mutations in SH2D1A, a gene that codifies for the regulatory protein SAP, result in uncontrolled activation of the SLAM (signaling lymphocyte-activation molecule) pathway. This X-linked immunodeficiency becomes evident when the patients are infected with Epstein Barr virus (EBV) and develop a fulminant form of infectious mononucleosis leading to a lymphoproliferative syndrome that is often fatal (X-linked lymphoproliferative syndrome, XLP). In those who survive, hypogammaglobulinemia and oncohematologic diseases are frequently observed. In this revision, the immuno-regulatory mechanisms involved in XLP immunopathology and the role of different effector cells (CD8 T lymphocytes, NK cells) are discussed.

CD34 and CD117 are overexpressed in AML and may be valuable to detect minimal residual disease.

We estimated by quantitative flow cytometry (FC) the expression of CD13, CD33, CD34 and CD117 antigens in cells from 64 patients with acute myeloid leukaemia (AML) and 22 normal bone marrows (BMs). The method converts fluorescence intensity into number of antigen molecules per cell, measured by antibody binding capacity (ABC). The number of molecules per cell in normal BM was 9.5+/-5.7 for CD13, 7+/-2.3 for CD33, 6+/-0.7 for CD34, and 6.3+/-1.5x10(3) for CD117. AML blasts expressed 11.4+/-12.4 molecules per cell for CD13, 9.5+/-9.7 for CD33, 74+/-2328.5 for CD34 and 12.5+/-33 x 10(3) for CD117. The number of CD34 and CD117 molecules were significantly higher in AML than in normals (P<0.0001 and P<0.05, respectively) while only in a few cases, CD13 and CD33 were abnormally expressed in myeloblasts. Our results indicate that quantitative analysis of CD34 and CD117 may be useful to detect minimal residual disease (MRD) and could be tested in a future to monitor therapy in AML.

Expresión de co-receptores para el virus de la inmunodeficiencia humana (VIH) luego del cultivo de leucócitos mononucleares (LM) de pacientes VIH+ / Human immunodeficiency virus (HIV) co-receptors expression in mononuclear leucocytes (ML) of HIV+ patients

Se estudiaron variaciones en la expresión de los co-receptores CXCR4 y CCR5 luego del cultivo no estimulado de LM de pacientes VIH+ por periodos de 3 a 20 días. El porcentaje de células CCR5+ descendió tanto en linfocitos T CD4+ como en T CD8+ luego de 7 días, manteniéndose disminuido hasta los 20 días. En cambio los niveles de CXCR4 se mantuvieron estables durante el cultivo en ambas subpoblaciones. En los cultivos de LM de donantes VIH- no hubo cambios significativos en la expresión de CCR5 ni en la de CXCR4. Para comprobar si la disminución de CCR5 estaba asociada a la replicación viral, se infectaron LM VIH- (pre-cultivados por 6 días) con sobrenadantes de cultivos de LM VIH+. Luego de 3 días de infección, la expresión de CCR5 se redujo tanto en linfocitos T CD4+ como en linfocitos T CD8+ , coincidiendo con la replicación viral durante el cultivo.