Elisabeth Legrand

Occult Hepatitis B Virus Infection in HIV-Infected Patients with Isolated Antibodies to Hepatitis B Core Antigen: Aquitaine Cohort, 2002–2003

We prospectively assessed the prevalence of occult hepatitis B virus (HBV) infection by investigating HBV replication in 160 human immunodeficiency virus (HIV)-infected patients with isolated antibodies to hepatitis B core antigen. This prevalence was 0.6% (1 case/160 patients; 95% confidence interval, 0%-3.4%). A second serum sample was collected later from 52 of the patients. HBV DNA was once again undetectable in all patients, except for the sole patient who had previously been found to be HBV DNA positive.

Characteristics of the cell populations involved in extra-thymic lymphosarcoma induced in C57BL/6 mice by RadLV-Rs

Abstract The viral isolate RadLV-Rs induces in C57BL/6 mice an extra-thymic lymphosarcoma characterized by a massive enlargement of spleen and lymph nodes, which results in 100% mortality within 100 days. The spleen is the primary focus of the disease whereas lymph nodes are secondarily invaded. Simultaneously mice display a mild anaemia and an increased spleen CFU content. The enlarged organs contain an heterogeneous cell population formed of T cells, B cells and cells in which neither T nor B marker could be detected (non-T non-B cells). In spleen, T cells initially increase and afterwards decline, whereas B cells expand constantly although at a slower rate than non-T non-B cells whose number reaches 5–10 times the normal range. An almost absolute unresponsiveness of spleen and lymph node cells to Con A and PHA is observed at every stage of the disease. Response of B cells to LPS is initially normal in lymph nodes but depressed in spleen. Afterwards it drops to nil value in both organs. Although the presence of suppressive cells was demonstrated in leukaemic spleens, an intrinsic unresponsiveness of some elements cannot be ruled out. Defect (or suppression) of the T sub-population involved in B maturation was suggested by the high levels of IgM and IgG 2 a and the simultaneously decreased values of IgA and IgG 1 in leukaemic mice sera. Experiments carried out with radio-chimaera restored with bone marrow differing by chromosome marker indicate that (a) cells necessary for leukaemia induction are provided by the progeny of the injected CFUs (b) very few progenitors need to be transformed to initiate the proliferative disorder. The present results indicate that the malignant proliferation belongs to the non-T non-B cell population.

Impairment of monocyte functions in advanced head and neck cancer

Depression of cell-mediated immunity is well established in most malignancies and especially in head and neck cancers, and much information is available concerning the defect in helper T lymphocyte function. We now report on impairment of the monocyte-macrophage system. Compared with normal controls we found that patients displayed, on one hand, an increased number of peripheral blood monocytes and, on the other hand, a smaller percentage of HLA-DR+ monocytes. Such peripheral blood monocytes normally failed to secrete factors, including interleukin 1 (IL-1). In addition, we observed that the in vivo induced blastogenesis of peripheral blood lymphocytes from patients, which is spontaneously depressed, is partly restored by medium containing IL-1. We cannot exclude, however, that the observed monocyte dysfunction involves other cytokines. Whether such an immune deficiency is due to secondary malnutrition or to the malignancy (or both) remains unclear.

Impact of protease inhibitors on intrahepatic hepatitis C virus viral load.

During chronic hepatitis C, hepatitis C virus (HCV) load in plasma was shown to be higher in HIV-co-infected than in immunocompetent patients [1]. The reason for this increased HCV replication is not known. It may be as a result of HIV-induced immune deficiency [2], although some authors did not find any correlation with the CD4 cell count [3]. A direct interaction between HCV and HIV was also hypothesized [4]. Protease inhibitors (PI) used in highly active antiretroviral therapy (HAART) have no HCV reduction effect during the first months of treatment [5-8]. However, a decrease in HCV plasma load was recently described in patients treated with HAART for a year [9,10]. We therefore investigated the potential impact of HAART on intrahepatic HCV load.

CD4 T Lymphocyte Proliferative Responses to Hepatitis C Virus (HCV) Antigens in Patients Coinfected with HCV and Human Immunodeficiency Virus Who Responded to Anti-HCV Treatment

CD4 T lymphocyte proliferative responses to hepatitis C virus (HCV) antigens were evaluated before and during an anti-HCV regimen (interferon-alpha2a and ribavirin) in 36 patients coinfected with HCV and human immunodeficiency virus (HIV), to determine whether immune responses against HCV antigens are present in such patients, whether these responses are modified by anti-HCV treatment, and whether they are correlated with treatment efficacy. The CD4 responses against HCV antigens (primarily core antigens) detected at study entry in one-half of the patients did not correlate with anti-HCV treatment efficacy. Of 36 patients, 8 had patterns of persistent immune response to infection by genotypes 3 or 4 that were significantly correlated with sustained virologic response. Persistent immunologic reactivity and sustained virologic response coexisted only in patients infected with genotype 3. These findings suggest that HCV genotype may influence specific immune response, which, in turn, is implicated in virologic control.

Plasma and Liver Hepatitis C Virus Variability in Patients Coinfected with Human Immunodeficiency Virus

ABSTRACT Liver and plasma hepatitis C virus (HCV) variability was compared by E2 cloning and sequencing in three patients coinfected with HCV and human immunodeficiency virus (HIV) before and after interferon treatment and in three patients solely infected with HCV. The plasma and liver samples contained unique sequences. In the patients coinfected with HIV, accumulated random mutations produced mostly nonsynonymous substitutions in contrast to the reduced HCV genetic variability seen after treatment.

Production of cytokines after lipopolysaccharide stimulation of murine spleen cells during lymphoma development in AKR mice

SummaryInjection of syngeneic lymphoma cells in AKR mice resulted in an important increase of splenic natural killer (NK) activity in the early days following the graft. Modifications of the production of different types of cytokine: interferon, interleukins 1 and 2, tumor necrosis factor (IFN, IL-1, IL-2, TNF), involved in the regulation of NK activity, were investigated in short-term cultures of total, adherent and non-adherent fractionated spleen cells, using lipopolysaccharide as the triggering or amplifying agent.Upon stimulation with lipopolysaccharide, splenocytes from lymphoma-grafted mice released a large amount of interferon as compared to controls with a maximum level 1 day after the graft. Equal amounts of IFN-γ and IFN-α/β were detected. Treatment of spleen cells prior to culture with anti-(asialo-GM1) or anti-(Thy-1.1) antibodies reduced interferon production by 80% and 50% respectively. This finding indicates that (a) the IFN-γ is produced by Thy-1-positive cells and (b) the production of IFN-γ by these cells is at least partially under the control of asialo-GM1-positive cells. We also showed that non-adherent fractionated spleen cells from lymphoma-grafted mice produced IL-1 and IL-2. IL-1 was released by asialo-GM1-positive cells and IL-2 by Thy-1-positive cells. Adherent cells released only IL-1. In contrast, total cells released smaller amounts of IL-1 and IL-2, suggesting a reciprocal inhibition between subpopulations of non-adherent and adherent cells. A high level of TNF production by adherent cells was observed only 4 days after the graft. These results indicate that graft of lymphoma cells entails important modifications of spleen cell populations releasing different types of cytokines implicated in NK activation.

Autologous monoclonal antibodies recognize tumour-associated antigens in X-irradiated C57BL/6 mice

X-irradiation of C57BL/6 mice induces thymic lymphosarcomas which sometimes contain retroviruses which upon injection into normal mice mimic the effect of the irradiation. We examined whether specific antigenicities, viral or cellular, were expressed by tumour cells that could be recognized by antibodies from the irradiated animals. We developed monoclonal antibodies (MAbs) using splenocytes of the diseased animal. The reactivity of such MAbs towards thymoma cell lines established in vitro was investigated by means of an ELISA. At least 10 antibody specificities were detected on the 13 tumours investigated, allowing separation of the MAbs into three classes: those recognizing the autologous tumour, heterologous tumours as well as normal thymic tissue, those specific for the autologous tumour, and those specific for one tumour, but not ones of autologous origin. The last two classes corresponded to specific tumour-associated antigens. Our panel of MAbs defined each tumour by the particular pattern of antigens harboured. It is striking that most of the antigens were present in the normal thymus and that only two tumours had additional antigenicities. Additionally, quantitative variations were observed in the levels of expression of these antigens.

Natural killer activity, production of interferon-gamma and interleukin 2 in immunodeficient C57BL/6 mice injected with RadLV-Rs viral complex.

Injection of the RadLV-Rs, a viral complex originally obtained from radio-induced thymic lymphosarcomas, into C57BL/6 mice induces a massive enlargement of spleen and lymph nodes. T- and B cell-proliferating populations display severe deterioration of their immune functions, resulting in death of the animals within three months. In contrast, the experiments reported here indicate that in such animals the natural killer (NK) activity is increased for about 2 months after viral injection. Interleukin 2 production is dramatically decreased, whereas interferon-gamma production is increased to twice the control value and thereafter decreases concomitantly with NK activity. This suggests that in RadLV-Rs-injected mice, the high NK activity is related to interferon-gamma production.

Protective effect of bone marrow and spleen suspensions on radiation-induced leukemogenesis in C57BL/6 mice

SummaryThe present experiments are an attempt to precise the type and localization of the cells involved in the protective effect of hemopoietic suspensions against the radiation-induced thymic lymphosarcoma (TLS) of C57BL/6 mice. Inocula containing variable numbers of BM or spleen CFUs from 60-day-old and 360-day-old donors were tested. According to their origin, the suspensions differed with respect to the CFU replication rate, the CFU ability to differentiate towards the T lineage and the content of the suspensions in thymic precursors. Two levels of inhibition were observed: BM suspensions from 60-day-old donors containing 1,500 CFUs had the best protective effect: 14.5% of TLS; 1,500 CFUs from 360-day-old donors were slightly but not significantly less efficient (28.5%). The second level of inhibition (36–46% of TLS) was obtained with all the following inocula:a) 1,200 and 300 spleen CFUs or 300 and 95 BM CFUs from 60-day-old donors,b) 1,500 spleen CFUs from aged donors. Seventy-six spleen CFUs from 60-day-old donors, 120 BM or 175 spleen CFUs from aged donors had no effect. These results suggest that in addition to the high replication rate of the BM CFUs as compared with spleen CFUs, cells endowed with an optimal protective effect are present in BM suspensions and are either absent or present in very small amount in spleen suspensions. These cells which induce an early repopulation of the thymus might correspond to thymic precursors.