Adult T-cell leukemia/lymphoma incidence rate in French Guiana: a prospective cohort of women infected with HTLV-1.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive malignancy caused by the human T-cell leukemia virus type 1 (HTLV-1). The incidence of ATL among HTLV-1 carriers remains largely unknown in endemic countries other than Japan as very few prospective studies have been performed. We assessed the ATL incidence rate among HTLV-1 infected women in a prospective cohort in French Guiana. This is the first prospective study to assess the ATL incidence rate in an area of South America where HTLV-1 prevalence is high. Patients were enrolled between 1991 and 2005, and follow-up continued until April 2018. In the general hospital in Saint-Laurent-du-Maroni, 307 pregnant women were diagnosed with HTLV-1 infection, and 268 of them were observed for a median of 16.7 years. During follow-up, 9 ATL incident cases occurred resulting in an ATL incidence rate of 2.03 per 1000 HTLV-1 carrier-years (95% confidence interval, 0.93-3.85 per 1000 HTLV-1 carrier-years). The median age at diagnosis was 47.4 years, and median survival from diagnosis was low at 3.5 months. The ATL incidence rate was elevated for a study population consisting mostly of young people, which could either be a general feature in South America or could be specific to the Noir Marron population that constituted most of the cohort.

[BIOETHICS LAWS AND REALITY ON THE GROUND DURING EPIDEMIOLOGICAL STUDIES IN FRENCH GUINEA AND CAMEROON]. / LOIS DE BIOÉTHIQUE ET RÉALITE DU TERRAIN LORS D'ÉTUDES ÉPIDÉMIOLOGIQUES EN GUYANE ET AU CAMEROUN.

The objective of this article is to describe the difficulties encountered, during the twenty last years, to obey the laws of bioethics in force during epidemiological investigations, carried out in French Guiana and in Cameroon. These research tasks aim to better understanding the transmission of two viruses: the human T lymphotropic retrovirus type 1 and the human herpes virus 8. These investigations, carried out in highly endemic villages, for one or two of these viruses, also aim at searching susceptibility genetic factors for infection in children by these viruses. They are scientific researches carried out in populations on low level of education and strong socio-economic constraints. These studies performed in general population are without benefit for the people. They require a collection of the family data, to build genealogic pedigrees, and a blood sampling. Using concrete examples, collected during field-investigations, we illustrate the problems encountered to apply, practically, the laws of bioethics. We will introduce and discuss thus the legislative framework in force, the studied populations, the concepts of preliminary information and informed consent, the adaptation necessary to take into account the local social organization and the importance of the family hierarchy. Lastly, the question of returned results of this kind of investigation will be discussed like that of the possible compensatory measures. This inventory reveals the limits of the current regulation, which is often poorly adapted to research in epidemiology in this kind of population and the ethical choices that has thus to be decided by the investigator.

Molecular epidemiology of merkel cell polyomavirus: evidence for geographically related variant genotypes.

Merkel cell polyomavirus (MCPyV) is linked to a cutaneous cancer mainly occurring in Caucasians. DNA from skin swabs of 255 adults, originating from the 5 continents, were subjected to MCPyV PCRs. Phylogenetic analyses demonstrate the existence of 5 major geographically related MCPyV genotypes (Europe/North America, Africa [sub-Saharan], Oceania, South America, and Asia/Japan).

Merkel cell polyomavirus infection occurs during early childhood and is transmitted between siblings.

Merkel cell polyomavirus (MCPyV) is thought to be the etiological agent of Merkel cell carcinoma, but little is known about its distribution and modes of transmission. We conducted seroepidemiological surveys in more than 1000 individuals, from two populations from Cameroon. Overall MCPyV seroprevalence was high in both populations (>75% in adults). Data from the first population, comprising mainly children, indicated that MCPyV infections mostly occurred during early childhood, after the disappearance of specific maternal antibodies. Results from the second family-based population provided evidence for familial aggregation of MCPyV infection status. We observed significant sib-sib correlation (odds ratio=3.42 [95% CI 1.27-9.19], p=0.014), particularly for siblings close together in age, and a trend for mother-child correlation (OR=2.71 [0.86-8.44], p=0.08). Overall, our results suggest that MCPyV infection is acquired through close contact, possibly involving saliva and/or the skin, especially between young siblings and between mothers and their children.

A new and frequent human T-cell leukemia virus indeterminate Western blot pattern: epidemiological determinants and PCR results in central African inhabitants.

Human T-cell leukemia virus (HTLV) indeterminate Western blot (WB) serological patterns are frequently observed in plasma/serum from persons living in intertropical areas. In the framework of ongoing projects on HTLV-1/2 and related viruses in Central Africa, we systematically analyzed plasma from villagers living in South Cameroon by WB. The group included 1,968 individuals (mean age, 44 years; age range, 5 to 90 years; 978 women/990 men), both Bantus (1,165) and Pygmies (803). Plasma samples were tested by WB analysis (MPD HTLV Blot 2.4) and interpreted according to the manufacturer's instructions. Only clear bands were considered in the analysis. Among the 1,968 plasma samples, 38 (1.93%) were HTLV-1, 13 (0.66%) were HTLV-2, and 6 (0.3%) were HTLV WB seropositive. Furthermore, 1,292 (65.65%) samples were WB sero-indeterminate, including 104 (5.28%) with an HTLV-1 Gag-indeterminate pattern (HGIP) and 68 (3.45%) with a peculiar yet unreported pattern exhibiting mostly a strong shifted GD21 and a p28. The other 619 (31.45%) samples were either WB negative or exhibited other patterns, mostly with unique p19 or p24 bands. DNA, extracted from peripheral blood buffy coat, was subjected to PCR using several primer pairs known to detect HTLV-1/2/3/4. Most DNAs from HTLV-1- and HTLV-seropositive individuals were PCR positive. In contrast, all the others, from persons with HTLV-2, HGIP, new WB, and other indeterminate patterns, were PCR negative. Epidemiological determinant analysis of the persons with this new peculiar WB pattern revealed that seroprevalence was independent from age, sex, or ethnicity, thus resembling the indeterminate profile HGIP rather than HTLV-1. Moreover, this new pattern persists over time.

A major locus on chromosome 3p22 conferring predisposition to human herpesvirus 8 infection.

Infection with human herpesvirus 8 (HHV-8), the etiological agent of Kaposi's sarcoma, has been shown to display strong familial aggregation, in countries in which HHV-8 infection is endemic. We investigated 40 large families (608 subjects aged one to 88 years) living in an isolated area of Cameroon in which HHV-8 is highly endemic. We performed a two-step genetic analysis for HHV-8 infection status (HHV-8+/HHV-8- determined by immunofluorescence) consisting of an initial segregation analysis followed by a model-based genome-wide linkage analysis. Overall HHV-8 seroprevalence was 60%, increasing with age. Segregation analysis provided strong evidence for a recessive major gene conferring predisposition to HHV-8 infection. This gene is predicted to have a major effect during childhood, with almost all homozygous predisposed subjects (∼7% of the population) becoming infected by the age of 10. Linkage analysis was carried out on the 15 most informative families, corresponding to 205 genotyped subjects. A single region on chromosome 3p22 was significantly linked to HHV-8 infection (LOD score=3.83, P=2.0 × 10(-5)). This study provides the first evidence that HHV-8 infection in children in endemic areas has a strong genetic basis involving at least one recessive major locus on chromosome 3p22.

Frequent and recent human acquisition of simian foamy viruses through apes' bites in central Africa.

Human infection by simian foamy viruses (SFV) can be acquired by persons occupationally exposed to non-human primates (NHP) or in natural settings. This study aimed at getting better knowledge on SFV transmission dynamics, risk factors for such a zoonotic infection and, searching for intra-familial dissemination and the level of peripheral blood (pro)viral loads in infected individuals. We studied 1,321 people from the general adult population (mean age 49 yrs, 640 women and 681 men) and 198 individuals, mostly men, all of whom had encountered a NHP with a resulting bite or scratch. All of these, either Pygmies (436) or Bantus (1085) live in villages in South Cameroon. A specific SFV Western blot was used and two nested PCRs (polymerase, and LTR) were done on all the positive/borderline samples by serology. In the general population, 2/1,321 (0.2%) persons were found to be infected. In the second group, 37/198 (18.6%) persons were SFV positive. They were mostly infected by apes (37/39) FV (mainly gorilla). Infection by monkey FV was less frequent (2/39). The viral origin of the amplified sequences matched with the history reported by the hunters, most of which (83%) are aged 20 to 40 years and acquired the infection during the last twenty years. The (pro)viral load in 33 individuals infected by a gorilla FV was quite low (<1 to 145 copies per 10(5) cells) in the peripheral blood leucocytes. Of the 30 wives and 12 children from families of FV infected persons, only one woman was seropositive in WB without subsequent viral DNA amplification. We demonstrate a high level of recent transmission of SFVs to humans in natural settings specifically following severe gorilla bites during hunting activities. The virus was found to persist over several years, with low SFV loads in infected persons. Secondary transmission remains an open question.

Multiple retroviral infection by HTLV type 1, 2, 3 and simian foamy virus in a family of Pygmies from Cameroon.

To better understand the origins and modes of transmission of HTLV-3 and to search for other retroviral infections (HTLV-1, HTLV-2, foamy viruses), we studied the family of a HTLV-3-infected individual (Pyl43), from Cameroon. Thirty-five persons were included. All adult men were still actively hunting nonhuman primates (NHP). All women were also butchering and cutting-up animals. Five persons reported a bite by an NHP. While HTLV-3 infection was only found in Pyl43, HTLV-1 and HTLV-2 infections were found, respectively, in 5 and 9 persons with one being co-infected by both retroviruses. Phylogenetic analysis suggested intra-familial transmission of HTLV-1 subtypes B and D and HTLV-2. One man was infected by a chimpanzee foamy virus, acquired probably 45 years ago, through a bite. Acquisition of retroviral infections still occurs in central Africa involving to various extent not only intra-familial transmission for HTLV-1/HTLV-2 but also direct interspecies transmission from NHP for foamy virus and possibly for HTLV-1 and HTLV-3.

The imprint of the Slave Trade in an African American population: mitochondrial DNA, Y chromosome and HTLV-1 analysis in the Noir Marron of French Guiana.

BACKGROUND: Retracing the genetic histories of the descendant populations of the Slave Trade (16th-19th centuries) is particularly challenging due to the diversity of African ethnic groups involved and the different hybridisation processes with Europeans and Amerindians, which have blurred their original genetic inheritances. The Noir Marron in French Guiana are the direct descendants of maroons who escaped from Dutch plantations in the current day Surinam. They represent an original ethnic group with a highly blended culture. Uniparental markers (mtDNA and NRY) coupled with HTLV-1 sequences (env and LTR) were studied to establish the genetic relationships linking them to African American and African populations. RESULTS: All genetic systems presented a high conservation of the African gene pool (African ancestry: mtDNA = 99.3%; NRY = 97.6%; HTLV-1 env = 20/23; HTLV-1 LTR = 6/8). Neither founder effect nor genetic drift was detected and the genetic diversity is within a range commonly observed in Africa. Higher genetic similarities were observed with the populations inhabiting the Bight of Benin (from Ivory Coast to Benin). Other ancestries were identified but they presented an interesting sex-bias. Whilst male origins spread throughout the north of the bight (from Benin to Senegal), female origins were spread throughout the south (from the Ivory Coast to Angola). CONCLUSIONS: The Noir Marron are unique in having conserved their African genetic ancestry, despite major cultural exchanges with Amerindians and Europeans through inhabiting the same region for four centuries. Their maroon identity and the important number of slaves deported in this region have maintained the original African diversity. All these characteristics permit to identify a major origin located in the former region of the Gold Coast and the Bight of Benin; regions highly impacted by slavery, from which goes a sex-biased longitudinal gradient of ancestry.

Meta-analysis on the use of zidovudine and interferon-alfa in adult T-cell leukemia/lymphoma showing improved survival in the leukemic subtypes.

PURPOSE: Human T-cell lymphotropic virus type-I-associated adult T-cell leukemia/lymphoma (ATL) is an aggressive, chemotherapy-resistant malignancy. Multiple small studies using zidovudine (AZT) and interferon-alfa (IFN-α) have shown response in patients with ATL. However, the impact of this innovative antiviral treatment strategy on long-term survival remains undetermined. PATIENTS AND METHODS: We report a meta-analysis of antiviral therapy of ATL. Medical records of 254 patients with ATL who were treated in the United States, the United Kingdom, Martinique, and continental France were individually reviewed. RESULTS: According to Shimoyama classification, there were 116 patients with acute ATL, 18 patients with chronic ATL, 11 patients with smoldering ATL, and 100 patients with ATL lymphoma. In 231 patients with available survival data, first-line therapy was recorded in 207 patients. Five-year overall survival rates were 46% for 75 patients who received first-line antiviral therapy (P = .004), 20% for 77 patients who received first-line chemotherapy, and 12% for 55 patients who received first-line chemotherapy followed by antiviral therapy. Patients with acute, chronic, and smoldering ATL significantly benefited from first-line antiviral therapy, whereas patients with ATL lymphoma experienced a better outcome with chemotherapy. In acute ATL, achievement of complete remission with antiviral therapy resulted in 82% 5-year survival. Antiviral therapy in chronic and smoldering ATL resulted in 100% 5-year survival. Multivariate analysis confirmed that first-line antiviral therapy significantly improves overall survival of patients with ATL (hazard ratio, 0.47; 95% CI, 0.27 to 0.83; P = .021). CONCLUSION: These results confirm the high efficacy of AZT and IFN, which should now be considered the gold standard first-line therapy in leukemic subtypes of ATL.

Evidence for a multiclonal origin of multicentric advanced lesions of Kaposi sarcoma.

BACKGROUND: Kaposi sarcoma (KS) is a complex tumor of uncertain clonality. Studying the viral clonality of the human herpesvirus 8 (HHV-8) in KS to determine clonality of the tumors, a strategy that has been used previously with Epstein-Barr virus and its associated tumors, may elucidate whether multicentric (disseminated) KS lesions correspond to metastatic lesions or to expansions of independent clones. METHODS: A series of 139 KS biopsies (from skin, lymph node, or tonsil) was obtained from 98 patients, with 59 biopsies from 18 patients with disseminated multicentric KS skin lesions. The degree of spindle cell infiltration in biopsies was established by direct observation of hematoxylin-eosin-stained sections, and HHV-8 viral load was quantified by real-time polymerase chain reaction. To determine cellular clonality, the size heterogeneity of the HHV-8-fused terminal repeat (TR) region was determined by probing of electrophoresed restricted genomic DNA from KS biopsies for the HHV-8 TR sequence. RESULTS: HHV-8 clonality analysis was performed on the 62 samples for which sufficient DNA was obtained. Most samples corresponded to histologically nodular lesions with high spindle cell infiltration and high viral load. A clonal HHV-8 pattern was determined for 59 samples; 11 were found to be monoclonal and 48 to be oligoclonal. The informative samples that were from disseminated KS skin lesions (n = 26, from six patients) were either monoclonal or oligoclonal, and the size of HHV-8 episomes varied between these samples. CONCLUSION: Although some tumor KS lesions were monoclonal expansions of HHV-8-infected spindle cells, most advanced lesions were oligoclonal proliferations. Furthermore, individual KS disseminated tumor skin lesions were found to represent distinct expansions of HHV-8-infected spindle cells. Thus, our results suggest that KS lesions, especially in patients with advanced skin tumors, are reactive proliferations rather than true malignancies with metastatic dissemination.

Simian foamy virus transmission from apes to humans, rural Cameroon.

Simian virus infections of humans are an increasing public health concern. Simian foamy virus (SFV) infections have been reported in persons occupationally exposed to nonhuman primates and in a few hunters in Cameroon. To better understand this retroviral zoonosis in natural settings, we studied persons who lived in southern Cameroon, near nonhuman primate habitats. First we studied a general population of 1,164 adults; 4 were SFV positive according to serologic and molecular assays. Then we studied 85 persons who reported having been bitten or scratched by nonhuman primates; 7/29 (24.1%) of those who had contact with apes (gorillas or chimpanzees) were SFV positive, compared with only 2/56 (3.6%) of those who had had contact with monkeys. These data demonstrate efficient transmission of SFVs to humans in natural settings in central Africa, specifically following ape bites, and viral persistence in the human host.

A major susceptibility locus for HTLV-1 infection in childhood maps to chromosome 6q27.

Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) is a human oncoretrovirus causing adult T-cell leukemia/lymphoma and chronic neuromyelopathy. We previously showed by segregation analysis that a dominant gene controls HTLV-1 infection through breast-feeding in children of African origin. Here, we report the mapping of this locus by a genome-wide linkage analysis based on the genetic model provided by segregation analysis. Five pedigrees of African origin with HTLV-1 seropositive children were included in the study. Significant evidence for linkage (LOD score of 3.36, P=0.00004) was obtained for chomosomal region 6q27 when using the robust analysis including only HTLV-1-infected subjects. When HTLV-1 seronegative children born to infected mothers were added in the analysis, a maximum LOD score of 2.79 (P=0.0002) was obtained for chomosome 2p25. This result was mostly due to the largest pedigree of our sample, which alone gave a LOD score of 2.90 (P=0.00013). We further excluded the role of exonic variants of two candidate genes located in the linked regions, CCR6 (chemokine receptor 6) in 6q27 and ID2 (inhibitor of DNA binding 2) in 2p25. Our results, mapping a major susceptibility locus to chromosome 6q27 and suggesting genetic heterogeneity with another locus at 2p25, pave the way to the determination of the molecular basis of predisposition to HTLV-1 infection in children.

Serological and molecular evidence that human herpesvirus 8 is endemic among Amerindians in French Guiana.

We evaluated the presence of human herpesvirus 8 (HHV-8) infection among groups of Amerindians in French Guiana. The overall prevalence of antibodies against lytic HHV-8 antigens was 23.0% (180/781), increasing from 18.4% in children <6 years old to approximately 30% in older persons (>45 years). Seroprevalence was higher in Amerindians living in remote localities than it was in those living in the coastal region. Analysis of a 725-base pair fragment of the K1 gene amplified from DNA from a Wayampi Amerindian showed that the virus belonged to molecular subtype E, which has hitherto been found in only a few Amerindians in Brazil and Ecuador.

Respective roles of serological status and blood specific antihuman herpesvirus 8 antibody levels in human herpesvirus 8 intrafamilial transmission in a highly endemic area.

Transmission of human herpesvirus 8 (HHV-8), the etiological agent of Kaposi's sarcoma, occurs mainly during childhood in endemic countries and, to a large extent, through intrafamilial contacts. To additionally investigate this familial transmission, and especially the role of plasma anti-HHV-8 antibody titers, we conducted a large survey in a village from Cameroon, Central Africa, including 92 families (608 individuals). Plasma samples were tested for specific IgG directed against HHV-8 lytic antigens by immunofluorescence assay, and titers were determined by 2-fold dilutions. Global HHV-8 seroprevalence was 60%, raising from 32% under 9 years up to a plateau of around 62% between 15 and 40 years. The familial correlation patterns in HHV-8 seropositive/seronegative status showed strong dependence from mother to child and between siblings. In contrast, no familial correlation in anti-HHV-8 antibody levels was observed among infected subjects. In particular, no relationship was observed between the anti-HHV-8 antibody titer of HHV-8 seropositive mothers and the proportion of their HHV-8 seropositive children. Furthermore, a random permutation study of the anti-HHV-8 antibody titers among HHV-8 infected subjects showed that the main risk factor for infection was the HHV-8 serologic status and not the antibody level. In addition, no correlation was found between anti-HHV-8 antibody levels and buffy coat HHV-8 viral loads in a subsample of 95 infected subjects. Overall, these results strongly suggest that, in this highly endemic population from Central Africa, HHV-8 transmission mainly occurs from mother to child and between siblings, and it is independent of plasma antibody levels of HHV-8 infected relatives.

Evidence for a recessive major gene predisposing to human herpesvirus 8 (HHV-8) infection in a population in which HHV-8 is endemic.

Infection by human herpesvirus 8 (HHV-8), as measured by the presence of specific antibodies, was shown in countries in which HHV-8 infection is endemic to exhibit familial aggregation and a peculiar variation with age (rapid increase until puberty followed by a plateau in young adults). To investigate whether host genetic factors could explain these findings, a segregation analysis was performed of 81 families of African origin (1623 subjects; HHV-8 seroprevalence, 11.9%) living in a village in French Guiana in which HHV-8 infection is endemic. Results provide evidence for a recessive gene controlling susceptibility or resistance to HHV-8 infection. This gene is predicted to have a major effect during childhood, with almost all homozygous predisposed subjects ( approximately 6% of the population) being infected by age 15. For nonpredisposed subjects, HHV-8 infection in childhood strongly depends on virus exposure (through an HHV-8-infected mother), whereas the risk of infection appears to be low in young adults, with no evidence for heterosexual transmission.