Human T lymphotropic virus type I (HTLV-I) infection in neurological patients in Salvador, Bahia, Brazil.

HTLV-I infection represents a major health concern in endemic areas throughout the world, such as Salvador, the main city of Bahia State, with socio-demographic characteristics similar to sub-Saharan African cities, located in the Northeast of Brazil. In order to provide an estimate of the frequency distribution, and range of neurological manifestations potentially related to HTLV-I infection in this city, we conducted a cross-sectional clinical-epidemiological study to determine the prevalence of this infection in patients with neurological diseases. Patients exhibiting vascular diseases, tumoral diseases or trauma were excluded. Over a period of 16 months, we studied 322 consecutive patients with chronic neurological diseases, who attended the neurological clinics of two major hospitals in Salvador. Overall, the prevalence of HTLV-I infection among the patients was 20.9% (67/320). However, the prevalence among the 104 patients with chronic myelopathy was 50.0% (52/104). It was observed that the major prevalence of HTLV-I was between the ages of 40 and 60 years with a female predominance. Our data indicate that, in Salvador city, HTLV-I is associated with chronic myelopathies or myeloneuropathies, which seem to be the only neurological diseases associated with HTLV-I.

Detection and localization by in situ molecular biology techniques and immunohistochemistry of hepatitis C virus in livers of chronically infected patients.

Hepatitis C virus (HCV) detection in the livers of chronically infected patients remains a debatable issue. We used immunohistochemistry, in situ hybridization (ISH) alone or after microwave heating with FITC-labeled probes, RT-PCR with unlabeled primers followed by ISH (RT-PCR-ISH), and in situ RT-PCR with FITC-labeled primers (in situ RT-PCRd) to localize the virus in 38 liver biopsy specimens from 21 chronically infected HCV patients treated with interferon-alpha (IFN-alpha). Biopsies were taken at the beginning and end of IFN-alpha treatment and 1 year later. Results were compared with that of HCV-PCR in serum. RT-PCR-ISH and in situ RT-PCRd showed HCV signal in all liver biopsies even in responders with seronegative HCV PCR. This signal was intranuclear, diffuse, or peripheral, in hepatocytes, bile ductule cells, and lymphocytes. Cytoplasmic signals were occasionally observed. Whereas the percentage of labeled hepatocytes remained constant, the number of labeled lymphoid follicles decreased after INF-alpha therapy. Immunohistochemistry resulted in the same pattern of positivity but it was weaker and inconstant. This study indicates the persistency of HCV latency in IFN-alpha responders 1 year after IFN-alpha treatment cessation, a finding that certainly deserves confirmation.

Complete nucleotide sequence of an African human T-lymphotropic virus type II subtype b isolate (HTLV-II-Gab): molecular and phylogenetic analysis.

We report the first complete nucleotide sequence of an African human T-cell lymphotropic virus type II. This new strain, called HTLV-II-Gab (Gab), was obtained from the uncultured peripheral blood mononuclear cells of a 44-year-old healthy Gabonese male who lived in a remote rural area, with neither history of blood transfusion nor sexual intercourse with non-Africans. Using nested PCR, 25 overlapping fragments, representing the entire proviral genome, were obtained, cloned and sequenced. The overall nucleotide sequence comparison with the four other available complete HTLV-II genomes indicated that Gab was more closely related to the HTLV-II subtype b prototypes (98.9, 99.3 and 98.2% nucleotide similarity with G12, NRA and GU respectively) than to the subtype a prototype (95.1% nucleotide similarity with Mo). Restriction profiles studies and phylogenetic analyses confirmed that Gab was a subtype b strain. However, this strain represents a newly described restriction fragment length polymorphism subtype, closely related to one of the rare partially sequenced African isolates originating from a pygmy living in Cameroon (PYGCAM). Nevertheless, the very low genetic divergence observed between this new African strain and the American strains raises several questions on the origins and level of genetic variability over time of this human retrovirus.

Viral infections and chemical exposures as risk factors for hepatocellular carcinoma in Vietnam.

A case-control study investigating risk factors for hepatocellular carcinoma (HCC) was conducted in Hanoi, in the north of Vietnam, between 1989 and 1992. Male cases of HCC (152) diagnosed in 2 hospitals were included. Hospital controls (241) admitted mainly to abdominal surgery departments were frequency-matched to cases for sex, age, hospital and place of residence (Hanoi, province). Odds ratios adjusted for matching variables and other potential confounders were estimated using unconditional logistic regression, or exact non-parametric statistical inference when numbers were small. Positivity for hepatitis B surface antigen (HBsAg) was the main risk factor for HCC in this sample. Five subjects (3 cases, 2 controls) had been infected by hepatitis C virus (HCV), and none of them were carriers of HBsAg, giving an OR of 38 associated with HCV infection among HBsAG-negative subjects. Alcohol drinking was associated with HCC and interacted with HBsAg positivity. Agricultural use of organophosphorous pesticides (30 liters/year or more) and military service in the south of Vietnam for 10 years or more were also associated with an increased risk of HCC. This study confirms the major role played by HBV infection and its association with HCC in south-east Asia. It also suggests how other factors such as alcohol consumption or exposure to chemicals may interact with HBV infection.

Absence of a relationship between antibodies to hepatitis C virus and hepatocellular carcinoma in Mozambique.

To study the relationship between hepatocellular carcinoma (HCC) and hepatitis C virus (HCV), sera from 178 patients with HCC and 194 blood donors from Maputo, Mozambique were tested for antibodies to HCV (anti-HCV) using a second generation enzyme-linked immunosorbent assay and a confirmatory test with six synthetic peptides as reagents. The presence of hepatitis B surface antigen (HBsAg) was tested using an enzyme immunoassay. The prevalence of anti-HCV was higher in patients with HCC than in controls, but the difference was not significant after adjustment for age. Therefore, this difference reflected a difference in the age structure between the two groups. The prevalence of HBsAg was higher in patients with HCC than in controls. There was a negative association between anti-HCV and HBsAg in patients with HCC that was not significant after adjustment for age. These serologic results, which contrast with previous reports, show the need for further studies on the relationship between HCC and HCV using second generation serologic tests and molecular biology techniques.

Anti-human immunodeficiency virus effects of zidovudine in combination with double-stranded RNA poly I poly C in T cells and monocytes-macrophages.

A comparison of the activity against human immunodeficiency virus 1 of zidovudine (AZT) and poly I poly C double-stranded RNA both alone and in combination in MT4 cells and primary monocyte/macrophage (M/M) cultures was made. The inhibition of the HIV-induced cytopathic effect or reverse transcriptase production by AZT in MT4 cells was not modified by the combination of the two agents. In contrast, AZT inhibition of reverse transcriptase production in the supernatant of M/M cultures was enhanced by the addition of poly I poly C. The inhibitory effect of the drug combination was more marked in M/M than in MT4 cells, indicating that the evaluation of compounds involving the induction of an antiviral state should be tested not only CD4+ T cells but also in monocyte-macrophages.

T activation marker evaluation in ARC patients treated with AZT. Comparison with CD4+ lymphocyte count in non-progressors and progressors towards AIDS.

Reductions in the percentage and absolute number of CD4+ lymphocytes, as well as abnormally high levels of activated peripheral T lymphocytes (CD3+ HLA-DR+ phenotype) and an increased proportion of CD8+ cells coexpressing the CD57 surface antigen (involved in natural killer activity) have been reported in HIV infection and associated with disease progression. We prospectively measured these subsets of lymphocytes in 34 patients with advanced AIDS-related complex (ARC) treated with azidothymidine (AZT). Peripheral blood lymphocyte phenotyping was performed before treatment, then at weeks 12 and 24. A striking fall in the proportion of activated T lymphocytes from baseline was observed (P less than 0.001) at week 24. In contrast, the percentage of CD4+ cells showed a slight and transient rise at week 12 (P less than 0.05). No modification in levels of CD8+ or CD8+ CD57+ cells was detected during the study. Of the 34 patients, 11 developed AIDS, and 23 remained AIDS-free during 51 weeks of follow-up. Similar patterns of change in CD4+ and HLA-DR+ CD3+ lymphocytes were found in the AIDS progressors and nonprogressors. Likewise, HIV p24 antigenaemia showed parallel decreases in both groups of patients. Although changes in CD4+ cells, p24 antigenaemia and HLA-DR-reactive T lymphocytes were not predictive of clinical outcome, large differences existed between the two groups prior to the initiation of therapy. The short-term onset of AIDS was associated with lower CD4+ cell numbers, higher levels of serum p24 antigen and a greater proportion of activated T lymphocytes. Our results suggest that the possible interest of T lymphocyte activation markers, in conjunction with conventional phenotyping, should be investigated further.

A highly defective HIV-1 strain isolated from a healthy Gabonese individual presenting an atypical western blot.

In central equatorial Africa the frequency of uninterpretable or atypical Western blots (WB)--ie. antibodies to gag proteins only--can represent up to 50% of enzyme-linked immunosorbent assay (ELISA)-positive samples. To date the significance of such serology remains unknown. Nevertheless, an unusual HIV-1 strain has been isolated from the blood of a healthy Gabonese individual who presented an atypical WB. This virus, identified as isolated HIV-1OYl, grew to low titres of reverse transcriptase activity (less than 50,000 cpm/ml) and was not obviously cytopathic. Radioimmunoprecipitation and peptide ELISA studies indicated that the lack of env-specific reactivity was probably due to the absence of antibodies to the viral glycoproteins, rather than the virus encoding a highly divergent envelope protein. Molecular cloning and sequencing of the provirus proved it to be a string of HIV-1 which was genetically closer to European and North American than to African strains. Furthermore the envelope protein sequence contained all the features of a typical HIV-1 env gene. However, the tat gene derived from the proviral clone was functionally defective. Site-directed mutagenesis of this gene showed that this was due to the substitution of an essential cysteine residue for a serine. Polymerase chain reaction amplification of the tat gene, as well as parts of the gag and env gene sequences of HIV-1OYl, showed that essentially all of the proviruses were defective. These data emphasize the need to view HIV isolates as populations of distinct genomes capable of complementing each other.

A study of liver HBV DNA during follow-up of acute viral hepatitis in children.

Twenty-nine children with acute icteric hepatitis were classified as follows after serological tests for the agents of viral hepatitis: hepatitis B 17 patients, hepatitis A 3 patients, hepatitis A + B 1 patient, possible non-A, non-B hepatitis 8 patients. In four of these cases, hepatitis A or non-A, non-B occurred in chronic HBsAg carriers. Hepatitis B virus (HBV) DNA was present in the initial serum of 15 of the 18 patients with acute hepatitis B. About 1 year after onset, HBsAg and HBV DNA were absent in 17 of them (16 of whom developed anti-HBs) and the remaining patient became a chronic HBsAg carrier without HBV DNA in his serum. At the same time, liver biopsy samples from all 29 patients were available for HBV DNA investigation. HBV DNA sequences in the liver were never found in any patient, neither under free form nor integrated into the cellular genome. The absence of HBV DNA integration in any of the liver samples taken about 1 year after the acute phase of hepatitis B suggests that such integration is either unlikely or is transitory during the symptomatic period.

Serological screening for hydatidosis in households of surgical cases in central Tunisia.

Household members of surgical cases of hydatidosis were screened for the disease in two high-risk districts in Central Tunisia. Seventy-four index cases were identified from the 1980-1984 surgical records of Sousse University Hospital. Household members over five years of age were tested by ELISA, and if positive by counterelectrophoresis (CEP) for detection of band 5. Positive subjects underwent a chest X-ray and echotomography (ECT). Eight of the 355 household members (2.2%) living in four different houses were serologically positive. All eight had a normal chest X-ray; a hepatic cyst was detected in seven of them. Five of the seven subjects in whom a cyst was diagnosed lived in two neighbouring houses (19 household members from the same family). Among these 19 subjects, six had been previously operated on for hydatidosis (cumulative rate: 11/19). The comparisons of these results with results obtained through community-based screening in the same area suggest that households members of patients are not at particularly high risk of hydatidosis.

Echotomographic and serologic screening for hydatidosis in a Tunisian village.

Echotomographic and serologic screening for hydatidosis was carried out in 1,650 subjects aged over 5 years in a village located in a high risk region of central Tunisia. Echotomography detected liver cysts in 6 subjects (prevalence rate: 3.6 per 1,000). These 6 cases were among the 7 positive cases detected by ELISA. In all 6, the diagnosis of liver cysts was confirmed. No other localization was found in any of the subjects including one with a positive ELISA and a normal echotomographic examination. This work demonstrates the high feasibility of echotomography in the field and confirms the high prevalence rate of hydatidosis in the community.