[Analysis of the ethical issues raised by a ten-year epidemiology program in French Guiana: limitations of the current legal framework and solutions adopted]. / Analyse des enjeux éthiques soulevés au cours d'un programme de recherche épidémiologique de dix années en Guyane française : limites de l'encadrement actuel et solutions adoptées.

BACKGROUND: This paper discusses the ethical aspects of a large research program in virology, conducted since 1994 and which has evolved in parallel with the elaboration of bioethics laws in France. This research, which involved the collection of a considerable amount of epidemiological data in the field, focused on epidemiological determinants (mother to child transmission, genetic susceptibility/resistance) of the human oncogenic retrovirus human T cell lymphotropic virus type 1 (HTLV-1). Data were collected from a specific population (Noirs Marrons) living in remote areas in French Guiana (South America). This ethnic group of African descent is highly endemic for HTLV-1 and associated adult T cell leukemia/lymphoma. The population has lived for two centuries on either side of the Maroni river, which constitutes the frontier between French Guiana and Surinam. The low socioeconomic and education levels of a large part of this population are mainly explained by a recent housing/residence fixation on the French side of the Maroni river. It is also linked to significant immigration from Surinam due to the civil war, which lasted for five years in the late 1990s, in this country. Conducting epidemiological surveys in this peculiar context illustrates the limitations of the available current legal framework in France for such studies. Indeed, several important ethical issues arose concerning not only individual and population benefits, but also specificities of the given information and of the informed consent. Another question concerns individual information feed-back in such a context of persistent viral infection, with a very low disease incidence, in a population with a relatively low education level. The goal of this work was mainly to report several of the ethical issues encountered and to discuss possible ways of achieving better information deliver and consent procedures in such a context. Indeed, these procedures should include new ideas and regulations promoting a real partnership, in order to conduct long-term epidemiological studies in populations with a low education level.

[HTLV1 infection and pregnancy]. / Infection par le rétrovirus HTLV-1 et grossesse.

OBJECTIVE: We report an epidemiological study with an analysis of the risk factors of the HTLV-1 seroprevalence in pregnant women and their children in the town of St Laurent du Maroni, French Guyana. MATERIAL AND METHOD: HTLV-1 seroprevalence and risk associated factors were first studied in all the pregnant women having delivered at St. Laurent between July 1991 and June 1993. Then, a retrospective analysis was performed in the children, aged between 18 months and 12 years old, born from HTLV-1 infected mothers, focusing especially on the duration of breast feeding and the level of HTLV-1 anti body titers and proviral load. RESULTS: The global HTLV-1 seroprevalence was 4.4% (75/1727) but it was more prevalent among ethnic groups of African origin such as the Noir Marron population (5.5%) and Haitians (6.3%). In the Noir-Marron population, which represents 70% of the studied population, HTLV-1 seropositivity was associated with a maternal age of>35 years, prior miscarriage, prior cesarean section, parity>4, gravidity>6 and negative rhesus factor. After logistic regression, HTLV-1 seropositivity remained associated with gravidity>6 and negative rhesus factor. Out of the 216 children born from 81 HTLV-1 infected mothers, only 21 were found to be HTLV-1 seropositive, giving a crude HTLV-1 transmission rate of 9.7% while among the 180 breast-fed children 10.6% were HTLV-1 seropositive. HTLV-1 seropositivity in children was associated with elevated maternal anti HTLV-1 antibody titer, high maternal HTLV-1 proviral load and child's gender, girls being more frequently HTLV-1 infected than boys. CONCLUSION: HTLV-1 infection, which can be responsible for severe pathologies in adults (adult T cell leukemia and tropical spastic paraparesis/HTLV-1 associated myelopathy) should be screened during pregnancy in women originating from high HTLV-1 endemic areas, as for France, mainly the French West Indies, French Guyana and Intertropical Africa. In case of HTLV-1 seropositivity, mothers should be informed on the risk of transmission and promotion of bottle feeding of their children should be strongly proposed.

CD4, CD8 and NK subsets in B-CLL.

Although B-CLL is a hematological disorder characterized by clonal proliferation of B-cells, in most cases an increase in absolute numbers of T cells is observed. This increase is probably polyclonal in nature, since most data indicate that T lymphocytes are not progeny of the malignant clone in B-CLL. As CD4, CD8 and NK cells correspond to heterogeneous populations, in this work we tried to better define these subpopulations. Thus, CD4 subpopulations were displayed by using double labelling techniques into helper inducer subset (CD4+CDW29+) and suppressor inducer subset (CD4+CD45R+). CD8 subpopulations were delineated according to density expression of CD8 and reactivity with CD16 and CD11b in: suppressive cells defined by high density (HD) CD8 and reactivity with CD11b; NK cells defined by low density (LD) CD8 and binding to CD16; CTL cells by LD or HD CD8 and absence of expression of CD16 and CD11b. Our results concerning 47 normal control donors and 27 B-CLLs indicated that: although percentages of cells expressing CD3, CD4, CD8 and NK markers are decreased, absolute values of these subpopulations were increased; there exists an imbalance concerning CD4 and CD8, given by a more important increase of CD8 than CD4 subpopulations, but both are significantly augmented when compared to the normal range; within CD4 subpopulations, there is an important increase of CD4 CDW29 subset (helper inducer) whereas the CD4 CD45R (suppressor inducer) is not augmented in stage A patients and decreases in stage C patients; all the 3 identified CD8 subpopulations (NK, suppressors and CTLs) appeared to be increased; in 3 cases of clonal remission CLL studied, all T cell and NK subpopulations were recovering to normal percentages.

Decrease of human T-cell lymphotropic virus type I prevalence and low incidence among pregnant women from a high endemic ethnic group in French Guiana.

To assess the prevalence and incidence of human T-cell lymphotropic virus type I (HTLV-I), 4,234 pregnant women of different ethnic origins were tested before each delivery between 1991 and 1997 in a high HTLV-I endemic area of French Guiana. HTLV-I was significantly more prevalent among ethnic groups of African descent as the Noir-Marrons (4.8%, 95% confidence interval [CI]: 4.0-5.6) and Haitians (5%, 95% CI 1.6-8.4). An age dependence of HTLV-I seroprevalence was observed. The mean age of Noir-Marron HTLV-I seronegative women was lower than for HTLV-I seropositive women (24. 7 vs. 28.6, p < 0.001). A decline in HTLV-I seroprevalence was observed, particularly in the Noir-Marron younger than 21 years old (p = 0.04). For five HTLV-I seroconversions observed, the incidence per 100 women-years in the Noir-Marron group was 0.19 (95% CI 0.02-0. 35) for all women, 0.32 in those 25 years old or younger (95% CI 0-0. 64), and 0.07 in those older than 25 years (95% CI 0-0.2). This observation was inconsistent with HTLV-I seroprevalence observed for those 25 years old or younger (2.8%) and those older than 25 (8.3%). These data demonstrate, for the first time outside Japan, a birth cohort effect for HTLV-I in a highly endemic ethnic group.

Serial study of CD5+ and CD5- B cell subpopulations in 335 HIV seropositive patients.

B cell subpopulations, as defined by double-labelling techniques with CD5 and CD19 monoclonal antibodies (MoAbs), were serially studied in 335 HIV-1 seropositive patients. At the time of the first consultation, no important modifications in either CD5+ or CD5- subpopulations were observed, whatever the stage of the disease. However, in 18 out of the 335 patients (5.37%), a sharp increase in B cells exceeding 20% and 300/mm3 was observed. This increase in B cells was mainly accounted for CD5-CD19+ B cell subpopulations and was associated with: (i) evolution of the disease, since only four patients presented it at their first consultation (one lymphadenopathy-associated syndrome (LAS) and three AIDS); (ii) advanced stages of disease since, at the time of B cell augmentation, two patients were staged as LAS, four as ARC and 12 as AIDS; (iii) a high incidence of non-Hodgkin's lymphomas (NHL) since three out of the 18 patients presented a histologically confirmed NHL and three others a clinical pattern compatible with this diagnosis. However, in three patients with B hyperlymphocytosis, polymerase chain reaction (PCR) studies of immunoglobulin gene rearrangement revealed the existence of a polyclonal expansion of B cells. These results justify inclusion of a pan-B cell marker in routine phenotypic studies of HIV-infected individuals, as well as the search for NHL among patients presenting this abnormality.

High levels of anti-cytoskeleton autoantibodies are frequently associated with chronic GVHD.

Twenty-two patients (acute myeloid leukaemia 13, acute lymphoid leukaemia 5, chronic myeloid leukaemia 4) with an average age of 25 years (range 8-36 years), had received allogeneic bone marrow transplantation (BMT) from an HLA identical sibling. The BMT recipients were followed up for a period of 4-65 months. All patients were given cyclophosphamide, total body irradiation and methotrexate in order to prevent graft-versus-host disease (GvHD). Eleven of 22 patients exhibited chronic graft versus host disease (cGvHD) (extensive in five, limited in six at the time of the study) assessed by clinical and histological parameters. Serum samples were collected from these patients, before BMT (except in one case) and then every 2 or 3 months. Sequential studies to determine the presence of autoantibodies against cytoskeletal proteins (actin, tubulin, myosin), dsDNA and dDNA in these sera were performed by an ELISA method. Simultaneously, immunoelectrophoresis and measurement of complement fractions C3, C4 were performed on each sample. High levels of autoantibodies against cytoskeletal proteins were found in 10/11 patients with cGvHD and were absent in 11/11 patients without cGvHD; none of them exhibited anti-DNA activity. At the same time, C4 levels were decreased in seven of these patients with cGvHD. Monoclonal immunoglobulins IgG and IgM (2-15 g/l) were found in 8/11, but the antibody activity was never found to be located within the M component. These results show a direct relationship between the presence of these autoantibodies and occurrence of cGvHD and indicate that they may constitute an immunological marker related to this complication. However, their predictive value is not clearly evident in this retrospective series as in some patients they preceded clinical signs of cGvHD, whereas in others they were associated with the onset of cGvHD.

Detection of a major gene predisposing to human T lymphotropic virus type I infection in children among an endemic population of African origin.

Human T lymphotropic virus type I (HTLV-I) is a human oncoretrovirus that causes an adult T cell leukemia/lymphoma and a chronic neuromyelopathy. To investigate whether familial aggregation of HTLV-I infection (as determined by specific seropositive status) could be explained in part by genetic factors, we conducted a large genetic epidemiological survey in an HTLV-I-endemic population of African origin from French Guiana. All of the families in 2 villages were included, representing 83 pedigrees with 1638 subjects, of whom 165 (10.1%) were HTLV-I seropositive. The results of segregation analysis are consistent with the presence of a dominant major gene predisposing to HTLV-I infection, in addition to the expected familial correlations (mother-offspring, spouse-spouse) due to the virus transmission routes. Under this genetic model, approximately 1. 5% of the population is predicted to be highly predisposed to HTLV-I infection, and almost all seropositive children <10 years of age are genetic cases, whereas most HTLV-I seropositive adults are sporadic cases.

Human herpesvirus 8 transmission from mother to child and between siblings in an endemic population.

BACKGROUND: Transmission of human herpesvirus 8 (HHV-8), the aetiological agent of Kaposi's sarcoma, is known to occur during sex among homosexual men. However, other modes of HHV-8 transmission remain to be elucidated in endemic populations. METHODS: We did a population-based seroepidemiological survey in a village in French Guiana among 1337 individuals of African origin (age 2-91 years) who had reliable genealogical data. Plasma samples were taken and tested for HHV-specific IgG by immunofluorescence assay. Risk factors and familial correlations for HHV-8 seropositivity were modelled by logistic regression analysis by use of the estimating equations approach, which expresses familial dependences in terms of odds ratios. Familial odds ratios were also acquired by use of the distribution of all possible pairs of a given familial dependence. FINDINGS: The overall HHV-8 seroprevalence was 13.2% with no difference according to sex. HHV-8 seropositivity was strongly age dependent: at 1.2% under 5 years, HHV-8 seroprevalence rose up to a plateau around 15% between 15 and 40 years, and showed a seroprevalence of more than 27% in individuals older than 40 years. Strong familial aggregation in HHV-8 seroprevalence was found with high mother-child (odd ratio 2.8 [95% CI 1.6-5.0]) and sib-sib (3.8 [1.6-9.5]) correlations. By contrast, no significant correlation between spouses (0.6 [0.2-1.9]) was seen. INTERPRETATION: This pattern of familial aggregation, together with the variation of HHV-8 seroprevalence with age, indicate that, in endemic populations, HHV-8 transmission mainly occurs from mother to child and between siblings during childhood and adolescence.

Risk factors for maternal HTLV-I infection in French Guiana: high HTLV-I prevalence in the Noir Marron population.

The aim of this study was to compare rates of human T-cell lymphotropic virus type I (HTLV-I) seroprevalence in pregnant women belonging to different ethnic groups in French Guiana and to determine the risk factors associated with HTLV-I seropositivity. All 1,873 deliveries between 1 July 1991 and 30 June 1993 in the only gynecologic and obstetric unit at Saint Laurent du Maroni were enrolled. Serologic status could be established for 1,727 women, with 75 (4.3%) being HTLV-I seropositive. The HTLV-I seroprevalence rate differed significantly between ethnic groups: 5.7% for Noir-Marron (70/1,302), 6.3% for Haitian (3/50), and 0% for Creole (126), Amerindians (166), and Hmong (64). In Noir-Marron pregnant women, HTLV-I seropositivity was associated with a maternal age of > 35 years [odds ratio (OR), 3.3; 95% confidence interval (CI), 1.4-7.6], prior miscarriage (OR, 1.7; CI, 1-2.8), prior cesarean section (OR, 2.1; CI, 1.1-4.0), a parity > 4 (OR, 4.0; CI, 1.8-8.8), a gravidity > 6 (OR, 4.2; CI, 2.0-7.2), and a negative Rhesus factor (OR, 2.2; CI, 1.1-4.5). Two separate stepwise logistic regressions were done because gravidity and parity were highly correlated. HTLV-I seropositivity remained associated with a gravidity > 6 (OR, 3.9; CI, 2.1-7.4) and a negative Rhesus factor (OR, 2.6; CI, 1.2-5.3) for the first model and with a parity > 4 (OR, 4.1; CI, 1.9-9.0) and a negative Rhesus factor (OR, 2.5; CI, 1.2-5.1) for the second model.(ABSTRACT TRUNCATED AT 250 WORDS)

Human T cell leukemia virus Type I (HTLV-I) infection induces greater expansions of CD8 T lymphocytes in persons with HTLV-I-associated myelopathy/tropical spastic paraparesis than in asymptomatic carriers.

A quantitative study of the T cell receptor repertoire was performed ex vivo on CD4 and CD8 T cell subsets of human T cell leukemia virus type I (HTLV-I)-infected asymptomatic carriers and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Indexes of oligoclonality that compiled all repertoire modifications were calculated for peripheral blood mononuclear cells and for CD4 and CD8 T cell subsets. Both patients with HAM/TSP and asymptomatic carriers had greater T lymphocyte expansions than did uninfected donors, which was independent of age and at least twice higher in the CD8 than in the CD4 cell compartment. Some expanded CD8 T cells corresponded to cytotoxic T lymphocytes directed against various epitopes of the immunodominant Tax protein. Patients with HAM/TSP had significantly higher CD8 cell expansions than did asymptomatic carriers. These results highlight the prognostic value of measuring CD8 T cell expansions during follow-up of HTLV-I infection.

Mother-to-child transmission of human T-cell-leukemia/lymphoma virus type I: implication of high antiviral antibody titer and high proviral load in carrier mothers.

In order to gain new insights into the risk factors influencing human-T-cell-leukemia/lymphoma-virus-type-I (HTLV-I) mother-to-child transmission, a retrospective study of HTLV-I infection among children born to HTLV-I-seropositive women was carried out in a highly HTLV-I-endemic population of African origin living in French Guyana. The study covered 81 HTLV-I-seropositive mothers and their 216 children aged between 18 months old and 12 years old. All plasma samples were tested for the presence of HTLV-I antibodies by ELISA, immunofluorescence assay and Western blot. HTLV-I provirus was detected, in the DNA extracted from peripheral-blood mononuclear cells, by polymerase chain reaction (PCR) using primers specific for 3 different HTLV-I genomic regions (LTR, gag and pX) and quantified by a competitive PCR assay. Out of the 216 children, 21 were found to be HTLV-I-seropositive, giving a crude HTLV-I transmission rate of 9.7%, while among the 180 breast-fed children 10.6% were HTLV-I-seropositive. Perfect concordance between serological and PCR results was observed, and none of the 195 HTLV-I-negative children was found HTLV-I-positive by PCR. In conditional (by family) logistic-regression models, HTLV-I seropositivity in children was associated with an elevated maternal anti-HTLV-I-antibody titer (OR 2.2, p = 0.0013), a high maternal HTLV-I proviral load (OR 2.6, p = 0.033) and child's gender, girls being more frequently HTLV-I-infected than boys: OR 3.6, p = 0.0077 in the model including maternal anti-HTLV-I-antibody titer and OR 4.1, p = 0.002 in the model including the maternal HTLV-I proviral load.

Demographic and familial characteristics of HTLV-1 infection among an isolated, highly endemic population of African origin in French Guiana.

To determine the epidemiological characteristics of human T cell leukemia/lymphoma virus type I (HTLV-I) infection in the endemic village of Maripasoula, French Guiana, 1,614 persons (83.2% of the population) aged 2 to 91 years (mean age 21) were studied from November 1994 through April 1995. Plasma samples were screened by an HTLV-I ELISA and an IFA test (on MT2 cells), and positive samples were tested by an HTLV-I and -II type-specific Western blot. Overall seropositivity in the village was 6.7%, but HTLV-I infection was restricted to 3 of 6 ethnic groups, including the Noir-Marron (descendants of escaped African slaves, 8%), the Creoles (4.1%) and those of mixed Noir Marron/other ethnicity (3.6%). In the Noir-Marron population of 1,222 persons, including 606 men and 616 women and representing 76% of those tested, HTLV-I seroprevalence increased significantly with age in both sexes, reaching 40% in women older than 50 years. Univariate risk factors for HTLV-I seropositivity in women included older age, more pregnancies, more live births and a history of hospitalization. A cross-sectional analysis of sexual partners demonstrated an excess of discordant female HTLV-I+/male HTLV-I- couples, indicating preferential male-to-female sexual transmission. The demonstration of II HTLV-I-seropositive children aged less than 15 years, of whom 9 had a seropositive mother, suggested maternal-child HTLV-I transmission. Our results demonstrate a very high seroprevalence of HTLV-I in this South American population descended from African slaves, probably due to high rates of mother-to-child and sexual transmission within this rather isolated group.