Anti-polymorphonuclear neutrophil antibodies in patients with leukopenia or neutropenia.

INTRODUCTION: Immune humoral neutropenia (Np) could be the consequence of anti-polymorphonuclear neutrophil (PMN) antibodies, circulating immune complexes (CIC) and/or antibodies against myeloid precursors. Granulocyte immunofluorescence test (GIFT) and a leukoagglutination technique (LAGT) assays are recommended for its diagnosis. METHODS: Fifty adult patients with secondary Np were screened for anti-PMN. GIFT by flow cytometry from viable PMN and LAGT were employed. In addition, CIC levels, low expression of CD16(b) (CD16 (b)(low)), PMN phenotype and sera tumor necrosis factor-alpha (TNF-alpha) were also evaluated. RESULTS: Direct IgG-PMN binding (dir-GIFT) was positive in 16% of the patients. Antibodies against autologous PMN were detected in 32% of the samples by indirect (ind)-GIFT and demonstrated in 70% of the sera by both ind-GIFT and/or LAGT. Predominance of human neutrophil alloantigen (HNA)-1b and HNA-2 expression was confirmed. CD16(b)(low) was detected in 16% of the patient's PMN and TNF-alpha in 68% of sera patients. CONCLUSION: Our results suggest that diagnosis of immune Np in the laboratory may be improved by focusing on patient's PMN together with the assessment of cellular markers.

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.

Anti-leukocyte antibodies as a consequence of HIV infection in HIV+ individuals.

Antibodies (Ab) that induce antibody-dependent cell-mediated cytotoxicity (ADCC) against non-T lymphocytes, anti-HLA class II specific Ab and anti-PMN were tested in hemophilic (He) patients who were alloimmunized because they had received replacement treatment with blood derivates and become infected with HIV, as well as in those who remained seronegative. In addition, the serum reactivity of spouses of HIV+ individuals and their children was studied to determine the effect of HIV infection in the absence of concomitant alloimmunization. The results of this study indicate that ADCC Ab were already present in HIV- He, suggesting the influence of alloimmunization. Their titer increased after appearance of HIV disease. While low reactivity against class II antigens was observed in HIV- He, activity augmented sharply after HIV infection and increased further with disease progression. Anti-PMN reactivity followed a similar pattern. Anti-class II, ADCC Ab and anti-PMN were also detected in the asymptomatic HIV+ spouses of HIV+ patients in titers that were similar to those of asymptomatic HIV+ He. In children born to HIV+ mothers in whom HIV infection was confirmed, anti-class II, ADCC Ab and anti-PMN reactivity were also observed, and activity increased after the onset of disease. These results suggest that induction of anti-leukocyte Ab occurs in the absence of massive allostimulation after HIV infection. HIV infection may enhance preexisting class II and anti-leukocyte response in allostimulated individuals.

Leukoagglutinins in patients with hemophilia.

Anti-leukocyte antibodies may occur in hemophilic patients as a consequence of replacement therapy with blood derivates. In this report we describe the presence of leukoagglutinins (LA) in serum of HIV-infected hemophiliacs (HIV + He) and their absence in HIV-negative patients (HIV-He). LA activity was recovered in IgG fractions from HIV + He, in the polyethylene glycol (PEG) precipitates from these sera, and in some cases in the supernatant fractions of PEG precipitates. Although the amount of PEG precipitates corresponding to circulating immune complexes (CIC) was higher in HIV + He than in HIV-He and normals, there was no direct relationship between CIC levels and LA. LA reacted both with autologous and with allogeneic polymorphonuclear leukocytes (PMN). In contrast to PMN isolated from HIV-He, HIV + He PMN had membrane associated IgG. In HIV + He, LA activity was more frequently observed in patients with more advanced stages of HIV infection than in asymptomatic individuals. Our results suggest that LA activity could be one of the manifestations of autoreactivity associated with progressing HIV infection in patients with hemophilia.

[Cytotoxicity induced by the serum of patients with AIDS and at high risk of AIDS against cells infected with Epstein-Barr virus]. / Citotoxicidad inducida por el suero de pacientes con SIDA y alto riesgo de SIDA (SAR) contra células infectadas por el virus de Epstein-Barr.

Serologic reactivity against EBV-infected lines was assayed in patients with AIDS (n = 4) or the AIDS related complex (AIDS-RC) (n = 46) residing in Argentina. Anti-VCA serology was comparable to that of controls. However sera from AIDS and AIDS-RC could induce antibody dependent cell mediated cytotoxicity (ADCC) to EBV-infected cell lines (P3HRIK and Raji). ADCC activity could be recovered in the high molecular weight fractions of AIDS and AIDS-RC sera. ADCC was observed in sera with high levels of PEG precipitable material (PEG-pp) but was unrelated to the presence of complement-fixing immune complexes (Clq-F) or to anti-VCA titers. Fc receptor (FcR) bridging between target cells FcR and effector cells FcR may play a role in the outcome of total ADCC.

Citotoxicidad inducida por el suero de pacientes con SIDA y alto riesgo de SIDA (SAR) contra células infectadas por el virus de Epstein-Barr / Cytotoxicity induced by serum of patients with AIDS and high risk of AIDS against infected cells by Epstein-Barr virus

En el suero de pacientes con síndrome de inmunodeficiencia adquirida (SIDA) y sujetos de alto riesgo de SIDA (SAR), se estudió la relación entre la actividad de anticuerpos anti-VCA, la presencia de complejos inmunes circulantes (CIC) y la capacidad de inducir la citotoxicidad dependiente de anticuerpo (CDA) de linfocitos normales contra líneas celulares infectadas con EBV. Se observó que los sueros de estos pacientes indujeron la CDA de linfocitos mononucleares (LM) normales contra células linfoblastoideas infectadas con EBV (P3HRIK y Raji). El título de anti-VCA en los pacientes con SIDA y SAR no difirió del grupo control normal. El contenido de IgG sérica y el nivel de CIC precipitable con PEG-PEG-pp) fue superior al normal. No se encontró relación entre PEG-pp y el nivel de CIC determinado por fijación de C1q (C1q-F). La CDA está favorecida por la presencia de CIC que actúan como puente entre receptores Fc (RFc) de las células P3HRIK y Raji y los LM efectores. De esta manera factores presentes en el suero de pacientes con SIDA y SAR pueden cooperar con LM normales no sensibilizados en la destrucción de células infectadas por EBV a través de la CDA clásica y la CDA mediada por los puentes RFc-RFc

Citotoxicidad inducida por el suero de pacientes con SIDA y alto riesgo de SIDA (SAR) contra células infectadas por el virus de Epstein-Barr / Cytotoxicity induced by serum of patients with AIDS and high risk of AIDS against infected cells by Epstein-Barr virus

En el suero de pacientes con síndrome de inmunodeficiencia adquirida (SIDA) y sujetos de alto riesgo de SIDA (SAR), se estudió la relación entre la actividad de anticuerpos anti-VCA, la presencia de complejos inmunes circulantes (CIC) y la capacidad de inducir la citotoxicidad dependiente de anticuerpo (CDA) de linfocitos normales contra líneas celulares infectadas con EBV. Se observó que los sueros de estos pacientes indujeron la CDA de linfocitos mononucleares (LM) normales contra células linfoblastoideas infectadas con EBV (P3HRIK y Raji). El título de anti-VCA en los pacientes con SIDA y SAR no difirió del grupo control normal. El contenido de IgG sérica y el nivel de CIC precipitable con PEG-PEG-pp) fue superior al normal. No se encontró relación entre PEG-pp y el nivel de CIC determinado por fijación de C1q (C1q-F). La CDA está favorecida por la presencia de CIC que actúan como puente entre receptores Fc (RFc) de las células P3HRIK y Raji y los LM efectores. De esta manera factores presentes en el suero de pacientes con SIDA y SAR pueden cooperar con LM normales no sensibilizados en la destrucción de células infectadas por EBV a través de la CDA clásica y la CDA mediada por los puentes RFc-RFc (AU)

Citotoxicidad inducida por el suero de pacientes con SIDA y alto riesgo de SIDA (SAR) contra células infectadas por el virus de Epstein-Barr. / [Cytotoxicity induced by the serum of patients with AIDS and at high risk of AIDS against cells infected with Epstein-Barr virus]

Serologic reactivity against EBV-infected lines was assayed in patients with AIDS (n = 4) or the AIDS related complex (AIDS-RC) (n = 46) residing in Argentina. Anti-VCA serology was comparable to that of controls. However sera from AIDS and AIDS-RC could induce antibody dependent cell mediated cytotoxicity (ADCC) to EBV-infected cell lines (P3HRIK and Raji). ADCC activity could be recovered in the high molecular weight fractions of AIDS and AIDS-RC sera. ADCC was observed in sera with high levels of PEG precipitable material (PEG-pp) but was unrelated to the presence of complement-fixing immune complexes (Clq-F) or to anti-VCA titers. Fc receptor (FcR) bridging between target cells FcR and effector cells FcR may play a role in the outcome of total ADCC.

Actividad citotoxica de leucocitos de pacientes chagasicos cronicos contra Trypanosoma cruzi. / Leukocyte cytotoxic activity of chronic Chagas' disease patients against Trypanosoma cruzi

Se estudio la actividad citotoxica de los leucocitos mononucleares (LM) y polimorfonucleares (PMN) de pacientes chagasicos cronicos contra epimastigotes de Trypanosoma cruzi en presencia de anticuerpos (suero autologo o de conejo inmune). Ambas clases de leucocitos fueron capaces de lisar los epimastigotes pero no se observo actividad citotoxica directa de los LM o PMN contra T. cruzi. La actividad promotora de la citotoxicidad y la fagocitosis de PMN del suero de los pacientes chagasicos se encontro en las fracciones de constante de sedimentacion 7S, asociada a la actividad aglutinante resistente a 2-ME indicando que se trata de IgG inmune. Este mecanismo podria ser activo en los pacientes chagasicos como barrera en la diseminacion de los parasitos