Brief survey of leprosy situation in Congo: sero-epidemiologic profile in correlation with some emerging viral infections.

The Democratic Republic of Congo (DRC, former Zaire) in central Africa remains the foremost country for leprosy in Africa, with a total of 4877 registered cases, of which 4573 are new cases since 1997. These numbers are well above the regional average. About 94% of these patients are under multidrug therapy (MDT) coverage in the Congo, which ranks 8th in coverage rate among the surrounding nine nations. Available data on anatomo-clinical profile and bacillarity are provided, with reservations on the use of these data drwn due to relatively small sample sizes. The seroprofile of the disease was reviewed with regard to the association of other immunity impairing infections like HBV infection and the recently highly incident retroviral epidemics (HIV-1, HTLV-1, and HTLV-2). The leading role of non-governmental organizations is cited for improving leprosy patient conditions and also for future prospects, where the necessity of coordinated strategies with the government is emphasized. Recommendations for new trends and steps relevant to improving existing and future leprosy control strategies are put into perspective.

Baculovirus-mediated expression of Plasmodium falciparum erythrocyte binding antigen 175 polypeptides and their recognition by human antibodies.

The erythrocyte binding antigen EBA-175 is a 175-kDa Plasmodium falciparum protein which mediates merozoite invasion of erythrocytes in a sialic acid-dependent manner. The purpose of this study was to produce recombinant EBA-175 polypeptide domains which have previously been identified as being involved in the interaction of EBA-175 with erythrocytes and to determine whether these polypeptides are recognized by malaria-specific antibodies. The eba-175 gene was cloned by PCR from genomic DNA isolated from the 3D7 strain of P. falciparum. The predicted protein sequence was highly conserved with that predicted from the published eba-175 gene sequences from the Camp and FCR-3 strains of P. falciparum and contained the F segment divergent region. Purified recombinant EBA-175 polypeptide fragments, expressed as glutathione S-transferase fusion proteins in insect cells by using the baculovirus system, were recognized by antibodies present in serum from a drug-cured, malaria-immune Aotus nancymai monkey. The fusion proteins were also recognized by antibodies present in sera from individuals residing in areas where malaria is endemic. In both cases the antibodies specifically recognized the EBA-175 polypeptide portion of the fusion proteins. Antibodies raised in rabbits immunized with the recombinant fusion proteins recognized parasite proteins present in schizont-infected erythrocytes. Our results suggest that these regions of the EBA-175 protein are targets for the immune response against malaria and support their further study as possible vaccine components.

Hepatitis B virus, alpha-fetoprotein synthesis, and hepatocellular carcinoma in Zaire.

We investigated the epidemiology of hepatocellular carcinoma (HCC) in Zaire, and evaluated the association between exposure to hepatitis B virus (HBV) and the development of HCC. Two hundred and twenty-three consecutive cases of HCC diagnosed over 19 years (1966-1985) were reviewed. HCC represented 8.32% of all carcinomas and 5.56% of all cancers. Frequency was higher in males (75.7%) than in females (24.3%); a sex ratio of 3/1. The majority (82.1%) of patients were aged 14 to 55 years with a peak occurrence in the fourth decade (28.6%). The mean age in males (41.27 +/- 17.5 years) and females (37.40 +/- 15.16 years) was significantly different (p < 0.02). Sera from 40 patients and 68 age and sex-matched controls were analyzed for markers of HBV infection: patients and controls had comparable rates of exposure (96% vs 72.1%, respectively). However, patients had significantly higher HBsAg carrier rates (56.7% vs 7.35%; p < 0.001), and lower anti-HBsAg seroconversion rates (25% vs 63.2%, p < 0.05). Using immunohistochemical analysis, the livers of patients were evaluated for HBsAg and HBcAg. These HBV antigens were more frequent in non-tumourous hepatocytes (53.3% vs 23.3%, respectively) than in HCC cells (13.3% vs 3.3%). Serum alpha-fetoprotein (AFP) was abnormal (> 20 ng/ml) in 90% of patients. The geometric mean (GM) AFP was 7273.8 ng/ml. AFP levels were significantly higher in HBsAg-positive HCC cases (GM: 19,322.6 ng/ml; 95% confidence interval (CI): [3639.2, 102,565.2]) than in antigen negative cases (GM: 1939.5 ng/ml; 95% CI: [182.8, 19,952.6]), but did not correlate with HBV replication. Immunohistochemical detection of AFP revealed a similar correlation between AFP and HBsAg. Neither AFP level nor HBsAg production correlated with cellular atypia or tumor grade.

Alpha-fetoprotein synthesis in human hepatocellular carcinoma: correlation with hepatitis B surface antigen expression.

We analyzed the pattern of alpha-fetoprotein (AFP) synthesis in 40 consecutive human hepatocarcinomas (HCC) in relation to hepatitis B viral (HBV) infection. In addition, histopathological characteristics of liver parenchyma and the tumor itself were examined. Elevated AFP (> 20 ng/ml) were found in 90% of HCC patients and in none of the controls. In 35% of HCC cases, serum AFP was above 100,000 ng/ml. AFP levels were significantly higher in patients seropositive for hepatitis B surface antigen (HBsAg) compared with their negative counterparts (mean log[AFP]: 4.28 +/- 1.67 vs. 3.28 +/- 1.96, respectively; geometric mean (GM): 19,322.6 ng/ml and 1939.5 ng/ml, respectively; p < 0.05). Furthermore, serum AFP levels were higher in HCC patients with liver cirrhosis than in those without (log[AFP]: 4.43 +/- 1.58 vs. 3.23 +/- 1.98, respectively; p < 0.05). However, the relationship of cirrhosis with AFP was confounded by the high prevalence of HBsAg in cirrhotic HCC patients. There was no correlation of AFP with either liver necrosis (abnormal AFP in 45% of cases; mean log[AFP]: 3.99 +/- 1.91 vs. 3.75 +/- 1.85 for HCC with and without necrosis, respectively; 0.05 < p < 0.68, not significant (NS)), or inflammation (abnormal AFP in 25%; mean log[AFP]: 4.33 +/- 1.62 vs. 3.70 +/- 1.93 for HCC with and without inflammation, respectively; 0.05 < p < 0.39, NS). A vast majority of HCC (75%) were moderately (grade 2-3) or poorly differentiated tumors (grade 3, grade 4, or combined grade 3-4). Serum AFP did not correlate with tumor grade. Immunohistochemical analysis of HBsAg and AFP confirmed the serological findings, and confirmed earlier observations of elevated AFP in HBsAg-positive patients. These results may reflect pathogenic and biological differences between HBsAG-secreting and nonsecreting HCC.

Histopathologic features of hepatocellular carcinoma in Zaire.

The pathology of hepatocellular carcinoma (HCC) was studied based on 223 Zairian HCC cases registered from 1966 to 1985. The observations included the following: (1) hepatitis B surface antigen (HBsAg) status, (2) histologic types, (3) degree of cellular differentiation, and (4) frequency and types of the accompanying cirrhosis. Serum HBsAg was positive in 56.7% of HCC patients and 5.7% of controls (P less than 0.001). Immunohistochemical localization of HBsAg was positive in 53.3% in normal hepatocytes and in 10% in neoplastic cells. Morphologically, mixed type HCC (48.4%), trabecular (31.4%), and compact variants (13.5%) were predominant. Clear cell and pseudoglandular variants were rare (less than 1%). The majority of tumors (83%) were poorly differentiated HCC (Grades: 2-3, 3, 3-4, and 4). Well-differentiated HCC were extremely rare (0.5%). Fifty percent of HCC arose in a cirrhotic liver, predominantly of the macronodular (67.4%) inactive (55%) type. The micronodular cirrhosis was very uncommon (1.1%). These findings clearly show the excess of poorly differentiated HCC in African patients and suggest a possible link between the morphologic features of HCC in Africa and its extraordinary fast-running course.