Factors involved in the generation of memory CD8+ T cells in patients with X-linked lymphoproliferative disease (XLP).

UNLABELLED: We have analysed the phenotype of T lymphocytes in two X-linked lymphoproliferative disease (XLP) patients with the same SH2D1A mutation differing in initial exposure to Epstein-Barr virus (EBV) and treatment. While memory T lymphocytes (with low CCR7 and CD62L expression) prevailed in both XLP patients, in patient 9, who developed acute infectious mononucleosis (AIM) and received B cell ablative treatment, the predominant phenotype was that of late effector CD8 T cells (CD27-, CD28-, CCR7-, CD62L-, CD45 RA+, perforin+), while in patient 4 (who did not suffer AIM) the prevalent phenotype of CD8 T lymphocytes was similar to that of normal controls (N) or to that of adult individuals who recovered from AIM: CD27+ , CD28+, CCR7-, CD62L-, CD45 RO+ and perforin-. CD57 expression (related to senescence) was also higher in CD8 T cells from patient 9 than in patient 4, AIM or N. Persistently high EBV viral load was observed in patient 9. The results obtained from this limited number of XLP patients suggest that events related to the initial EBV encounter (antigen load, treatment, cytokine environment) may have more weight than lack of SH2D1A in determining the long-term differentiation pattern of CD8 memory T cells.

HCV recovery from peripheral blood mononuclear cell culture supernatants derived from HCV-HIV co-infected haemophilic patients with undetectable HCV viraemia.

Hepatitis C viraemia, in 38 human immunodeficiency virus positive (HIV+)/hepatitis C virus positive (HCV+) patients, was determined in haemophilic patients during the 4 years since initiation of highly active antiretroviral therapy (HAART). Six of 38 patients had persistently HCV-negative viraemia for more than 2 years. No correlation between HCV-negative viraemia and CD4+ T-cell counts, HIV viral load, age, type or severity of haemophilia could be established. Reduced levels of HIV viral load and the immune reconstitution that follows the initiation of HAART were not enough to explain the disappearance of HCV from plasma. Individuals who cleared plasma HCV had significantly higher CD8+ T-cell counts (P=0.0013) (mean +/- SE: 1153 +/- 117.8 cells microL(-1)) than those with HCV-positive viraemia (819.1 +/- 40.72 cells microL(-1)). Because HCV could maintain a low replication level in peripheral blood mononuclear cells (PBMC), we cultured PBMC of five of six patients with undetectable HCV viraemia. We found four of five HCV RNA-positive cultures. The presence of HCV RNA in our cultures proved that these cells may be an important viral reservoir that could contribute to HCV recurrence in plasma even after long periods of negative viraemia. In summary, our results indicate that in spite of prolonged HCV-negative plasma viraemia, HCV patients that are co-infected with HIV may harbour replication-competent HCV in their PBMC. Therefore, true clearance of HCV infection is difficult to achieve in these patients.

Reservoirs of HIV replication after successful combined antiretroviral treatment.

Sustained reduction of viral replication can be achieved in HIV infected patients after treatment with combinations of drugs (HAART) that inhibit the viral reverse transcriptase, and protease enzymes. However, replication competent virus can still be recovered from latently infected resting memory CD4+ T-cell lymphocytes. Moreover, "covert" virus replication has been demonstrated in patients who experienced reductions in plasma viremia to levels below the limit of detection of the most sensitive PCR assays. In most studies, preferential attention has been given to latent resting CD4+ T-lymphocytes as a source of HIV persistence. However, insufficient suppression of HIV replication could also lead to viral re-emergence after HAART interruption. In addition to CD4+ T- lymphocytes, other host cells such as long-lived resident macrophages or recently infected blood monocytes could also contribute to maintain persistent HIV replication after HAART. Establishing the origin of re-emerging HIV in patients under HAART upon treatment interruption is important to design optimal treatment schemes. Therapeutic strategies aimed at reducing the number of latently infected cells involve immune activation with IL-2, or other stimulatory factors, in the presence of antiretroviral drugs. Elimination of replication-competent virus would require intensification of HAART, or the use of antiretroviral drugs achieving an effective concentration at the site of HIV replication. In this review the mechanisms of HIV persistence and the methods that can be used to distinguish latent from covert HIV replication in different cell types will be discussed.

Immortalized Epstein-Barr virus-positive B-cell lines obtained by prolonged culture of peripheral blood mononuclear cells from human immunodeficiency virus type 1-positive patients.

OBJECTIVES: To study the factors that determine malignant B cell growth in human immunodeficiency virus type 1 (HIV-1)-infected patients. STUDY DESIGN: B-cell lines (lymphocyte cell lines [LCL]) were developed after nonstimulated culture of peripheral blood mononuclear cells (PBMC) from HIV-1-positive (HIV-1(+)) patients. Human immunodeficiency virus type 1 replication in culture, Epstein-Barr virus (EBV) latent oncogene expression, and cell-to-cell interaction were studied after nonstimulated culture of HIV-1(+) PBMC, analyzing their contribution to LCL appearance. METHODS: Nonstimulated PBMC cultures of HIV-1(+) PBMC and controls (N-PBMC) were established. Lymphocyte cell lines were characterized. Epstein-Barr virus latent membrane protein 1 (LMP-1) and Epstein-Barr nuclear antigen 2 were detected by polymerase chain reaction (PCR). Clonality of LCL was determined by light chain restriction (flow cytometry) and immunoglobulin H chain rearrangement (semi-nested PCR). Peripheral blood mononuclear cell phenotypes were studied at different intervals of culture. RESULTS: Lymphocyte cell lines were obtained in 73% of HIV-1(+) PBMC cultures, compared with 6% in N-PBMC. All LCL were EBV-positive (EBV(+)). B-cell lineage was established, and up to 12 different B-cell clones were expanded from the same individual. Occurrence of LCL was more frequent in cultures with HIV-1 replication, high LMP-1 expression in viable B cells, and high CD4:CD8 ratio. Human immunodeficiency virus type 1 replication persisted in 53% of the LCL. CONCLUSIONS: In vitro HIV-1 replication and persistence of viable EBV(+) lymphoblasts favor spontaneous in vitro outgrowth of LCL in HIV-1(+) patients.

Monocyte differentiation and HIV replication after prolonged culture of peripheral blood mononuclear cells from HIV-infected individuals.

Primary cultures of peripheral blood mononuclear cells (PBMC) from 51 HIV+ hemophiliac patients (HIV+ PBMC) were set up, allowing undisturbed cellular interaction in the absence of any exogenous stimuli. The optimum time for p24 detection was between 12 and 25 days. Infective virus was recovered from the culture supernatants (HIV+ SN) and the amount of p24 released ranged from 25 to 5300 pg/ml. Cells of the monocyte/macrophage (M/M) lineage were the main source of HIV in the HIV+ SN, as judged by intracellular staining of permeabilized cells with anti-p24 (KC57 monoclonal antibody) and flow cytometry analysis. M/M activation, differentiation, and proliferation occurred along the culture before the peak of in vitro HIV replication. Release of HIV p24 was highest in patients with >200 CD4+ T lymphocytes/mm3 who did not receive highly active antiretroviral therapy (HAART), but it was still detectable in 60-90% of patients who had responded to 1-2 years of HAART, reducing their plasma viral load to undetectable levels. It is proposed that this simple experimental system can be used to assess ongoing HIV infection of M/M with the patient's own viral variants.

[HIV infected macrophages isolated from HIV+ patients with undetectable viral load undergoing combined antiretroviral treatment]. / Macrófagos infectados por HIV aislados de pacientes HIV+ con carga viral indetectable luego del tratamiento antirretroviral combinado.

A new method of culture of peripheral blood leukocytes (PBMC) from HIV+ patients, in the absence of exogenous stimuli (allogeneic cells or cytokines) (PBMC w/s) was used for the detection of persistent viral infection in HIV patients who had undergone successful highly active antiretroviral therapy (HAART) lowering their viral burden to undetectable levels (< 50 RNA copies/ml). Infected cells were always of the monocyte/macrophage lineage (M). No infection could be detected in these patients using the classical system (co-culture with HIV-CMP activated with PHA and IL-2). Differences in the class of target cells (higher proportion of proliferating M and CCR5 expressing cells in the PBMC w/s system than in PBMC-PHA cultures) may determine the relative sensitivity of each technique to achieve successful isolation of HIV from different patients.

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

Variations of the expression of CXCR4 and CCR5 HIV co-receptors after non stimulated culture of peripheral blood mononuclear cells (PBMC) from HIV+ patients were studied. Expression of CCR5 on both CD4+ and CD8+ T lymphocytes was reduced after 7 days and remained low throughout the culture. CXCR4 levels remained stable in both lymphocyte subpopulations. No significant changes were observed in control HIV- PBMC cultures. In order to ascertain if the CCR5 changes were associated to in vitro HIV replication, 6 days pre-cultured HIV- PBMC were infected with HIV+ culture supernatants. After 3 days CCR5 expression was reduced both in CD4+ and in CD8+ T lymphocytes, while CXCR4 expression was not, coincident with initiation of HIV replication in culture. These results suggest that CCR5 down modulation in CD4+ or CD8+ T lymphocytes is a consequence of HIV replication.

Macrófagos infectados por HIV aislados de pacientes HIV+ con carga viral indetectable luego del tratamiento antirretroviral combinado. / [HIV infected macrophages isolated from HIV+ patients with undetectable viral load undergoing combined antiretroviral treatment]

A new method of culture of peripheral blood leukocytes (PBMC) from HIV+ patients, in the absence of exogenous stimuli (allogeneic cells or cytokines) (PBMC w/s) was used for the detection of persistent viral infection in HIV patients who had undergone successful highly active antiretroviral therapy (HAART) lowering their viral burden to undetectable levels (< 50 RNA copies/ml). Infected cells were always of the monocyte/macrophage lineage (M). No infection could be detected in these patients using the classical system (co-culture with HIV-CMP activated with PHA and IL-2). Differences in the class of target cells (higher proportion of proliferating M and CCR5 expressing cells in the PBMC w/s system than in PBMC-PHA cultures) may determine the relative sensitivity of each technique to achieve successful isolation of HIV from different patients.

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

Variations of the expression of CXCR4 and CCR5 HIV co-receptors after non stimulated culture of peripheral blood mononuclear cells (PBMC) from HIV+ patients were studied. Expression of CCR5 on both CD4+ and CD8+ T lymphocytes was reduced after 7 days and remained low throughout the culture. CXCR4 levels remained stable in both lymphocyte subpopulations. No significant changes were observed in control HIV- PBMC cultures. In order to ascertain if the CCR5 changes were associated to in vitro HIV replication, 6 days pre-cultured HIV- PBMC were infected with HIV+ culture supernatants. After 3 days CCR5 expression was reduced both in CD4+ and in CD8+ T lymphocytes, while CXCR4 expression was not, coincident with initiation of HIV replication in culture. These results suggest that CCR5 down modulation in CD4+ or CD8+ T lymphocytes is a consequence of HIV replication.

[Apoptosis and human immunodeficiency virus infection (HIV]. / Apoptosis e infección por el virus de la inmunodeficiencia humana (HIV).

Generalized activation of the immune system after HIV infection leads to an exacerbation of all apoptotic mechanisms. CD4+, CD8+ T lymphocytes and B lymphocytes are sensitized to apoptotic stimuli. Macrophages are important in the removal of apoptotic cells, they prevent apoptotic cell accumulation during in vitro culture and they may lead to enhanced CD4+ T lymphocyte cell death through indirect mechanisms. A simple procedure for prolonged culture of peripheral blood mononuclear cells from HIV+ patients is discussed, in relation to its convenience to evaluate apoptosis, cell to cell interaction and HIV replication in the absence of exogenously added stimuli or co-culture of allogeneic cells. In this system, HIV replication takes place primarily in cells of macrophage lineage that may be activated into differentiation through removal of apoptotic debris during the culture.

Apoptosis e infección por el virus de la inmunodeficiencia humana (HIV) / [Apoptosis and human immunodeficiency virus infection (HIV]

Generalized activation of the immune system after HIV infection leads to an exacerbation of all apoptotic mechanisms. CD4+, CD8+ T lymphocytes and B lymphocytes are sensitized to apoptotic stimuli. Macrophages are important in the removal of apoptotic cells, they prevent apoptotic cell accumulation during in vitro culture and they may lead to enhanced CD4+ T lymphocyte cell death through indirect mechanisms. A simple procedure for prolonged culture of peripheral blood mononuclear cells from HIV+ patients is discussed, in relation to its convenience to evaluate apoptosis, cell to cell interaction and HIV replication in the absence of exogenously added stimuli or co-culture of allogeneic cells. In this system, HIV replication takes place primarily in cells of macrophage lineage that may be activated into differentiation through removal of apoptotic debris during the culture.

Apoptosis e infección por el virus de la inmunodeficiencia humana (HIV). / [Apoptosis and human immunodeficiency virus infection (HIV]

Generalized activation of the immune system after HIV infection leads to an exacerbation of all apoptotic mechanisms. CD4+, CD8+ T lymphocytes and B lymphocytes are sensitized to apoptotic stimuli. Macrophages are important in the removal of apoptotic cells, they prevent apoptotic cell accumulation during in vitro culture and they may lead to enhanced CD4+ T lymphocyte cell death through indirect mechanisms. A simple procedure for prolonged culture of peripheral blood mononuclear cells from HIV+ patients is discussed, in relation to its convenience to evaluate apoptosis, cell to cell interaction and HIV replication in the absence of exogenously added stimuli or co-culture of allogeneic cells. In this system, HIV replication takes place primarily in cells of macrophage lineage that may be activated into differentiation through removal of apoptotic debris during the culture.

Increased CD4-positive monocytes in HIV-infected haemophilic patients.

The monocyte-macrophage system is known to play a central role in HIV infection, and expression of CD4 on the surface of monocytes/macrophages is important, since this molecule is a key factor for the entrance of HIV into susceptible cells. In this paper we evaluated the expression of CD4 in monocytes of haemophilic patients (He) who had been infected with HIV (HIV + He) through transfusion of contaminated plasma concentrates. Thirty seropositive patients (HIV + He), 10 seronegative He patients (HIV-He) and 20 voluntary normal blood donors were studied. Phenotypic evaluation of monocytes was performed by flow cytometry of peripheral blood stained with anti-CD45, -CD3, -CD4 and -CD14 monoclonal antibodies. The percentage of CD4 monocytes was increased in all HIV+ patients groups, but it was highest in those belonging to Groups III and IV A of the CDC classification. Furthermore, the median of fluorescence intensity of CD4+ monocytes from individual patients was shifted to the right, indicating expression of increased numbers of CD4 molecules on the cell membrane of monocytes. This could in turn favour HIV infection and viral persistence, facilitating in vivo dissemination of the virus.

Macrophages, multinucleated giant cells, and apoptosis in HIV+ patients and normal blood donors.

Clearance of apoptotic debris is carried out by cells of the monocyte/macrophage lineage and, as other macrophage functions, it can be altered in AIDS, leading to the accumulation of apoptotic cells observed in this disease. In this study we evaluated the ability of macrophages from human immunodeficiency virus (HIV)-infected patients to differentiate and to clear apoptotic debris in prolonged in vitro cultures. Peripheral blood mononuclear cells (PBMC) from infected hemophilia patients were cultured in the absence of exogenously added stimulators and the organization and morphological characteristics of the cultures were analyzed and correlated with clinical staging of the patients. Cell aggregates of different sizes involving macrophages and lymphocytes were formed in cultures from asymptomatic HIV+ patients (CDC groups II-III) and controls and in 4/7 group IV C2 HIV+ patients. In order to obtain viable and organized cultures, cells had to be handled carefully, allowing contact and undisturbed sedimentation in round-bottom tubes. Multinucleated giant cells (MGC) were formed through macrophage fusion after 5 days of culture in HIV- controls, group II and III patients, and some of the group IV C2 patients, while scarce formation of MGC was observed in AIDS patients or patients with advanced HIV disease. This paucity was correlated with impaired dead cell removal and accumulation of apoptotic debris. Viability of macrophages and MGC was reduced after 15 days. MGC and the macrophages (either free or in cell aggregates) were able to remove dead cells, clearing the cultures of cell debris. Furthermore, in group II and III HIV+ hemophilic patients, increased macrophage-MGC phagocytic activity, suggesting in vivo activation, was frequently observed. In HIV+ patients with AIDS or advanced HIV disease (CDC groups IV A, IV C1, and IV D) dead cell removal was impaired and apoptotic debris accumulated. Long-term cultures of unstimulated PBMC are an interesting model for studying the role of macrophages and/or MGC in the removal of dead cells as well as examining the cellular milieu in which HIV replicates in an individual host.

[Apoptosis. Its role in the immune system ontogeny and in HIV infection]. / Apoptosis. Su papel en la ontogenia del sistema inmune y en la infección por HIV.

Apoptosis is a physiologic process whereby undesired cells are eliminated in a non-inflammatory way. It is characterized by cellular retraction, clumping of nuclear chromatin and DNA retraction followed by DNA degradation into oligonucleosomes formed by 180-185 base pairs or multiples of these units that can be identified electrophoretically. The plasma membrane and organelles are well conserved until the final stages of the process. Apoptosis is central to many of the functions of the immune system. A review of its role in the immune system as well as in AIDS is presented, as well as a brief description of the methodology that can be followed for the assay of apoptosis.

Apoptosis. Su papel en la ontogenia del sistema inmune y en la infección por HIV. / [Apoptosis. Its role in the immune system ontogeny and in HIV infection]

Apoptosis is a physiologic process whereby undesired cells are eliminated in a non-inflammatory way. It is characterized by cellular retraction, clumping of nuclear chromatin and DNA retraction followed by DNA degradation into oligonucleosomes formed by 180-185 base pairs or multiples of these units that can be identified electrophoretically. The plasma membrane and organelles are well conserved until the final stages of the process. Apoptosis is central to many of the functions of the immune system. A review of its role in the immune system as well as in AIDS is presented, as well as a brief description of the methodology that can be followed for the assay of apoptosis.

[HIV-1 infection in patients with hemophilia. The Argentinian experience from 1983 to 1990]. / Infección por HIV-1 en pacientes con hemofilia. La experiencia Argentina desde 1983 hasta 1990.

We present studies on the evolution of HIV-1 infection in 638 hemophilic patients receiving commercial antihemophilic concentrates (CAH) at the Institute of Hematological Research and the Argentine Foundation of Hemophilia between 1983 and 1990. Positive serology for HIV-1 was detected in 30% of the patients studied. Prevalence of HIV-1 infection was higher (about 70%) in the group with severe hemophilia requiring more CAH, but there were no differences between patients with hemophilia A or B. Sexual transmission was demonstrated in 8/64 women (13%) with stable sexual relationship with HIV-1 + hemophilic patients. Three of them became pregnant, and HIV-1 infection was demonstrated in two of the three children. In general, the clinical evolution, as well as the hematologic and immunologic parameters of infected patients were similar to those described for the hemophilic population in other occidental countries. Opportunistic infections were also those observed elsewhere (with predominance of P. carinii pneumonia and disseminated Candida infections). However, the presence of fatal chagasic encephalitis in two of the patients with AIDS is unusual. Thus, central nervous system localization of T. cruzi (which can be observed during the acute period of T. cruzi infection or in immunosuppressed patients), must be considered as a possible severe complication of HIV-1 disease in T. cruzi infected patients.