PURPOSE: This study was designed to find a reliable Epstein-Barr virus (EBV) immunoglobulin (Ig) G-based diagnostic/screening test for nasopharyngeal carcinoma (NPC) able to demarcate between the NPC-related seropositivity of EBV IgG antibodies and that of other head and neck cancer (HNCA) and control groups. The NPC-associated immunosuppression affects EBV IgA much more than IgG, leading to inconsistent detection of NPC using EBV IgA antibodies.
MATERIALS AND METHODS: One hundred twenty-two HNCA patients, 42 NPC, 66 laryngeal carcinoma, and 14 hypopharyngeal carcinoma and 3 groups of 100 control subjects were enrolled in this study. Enzyme-linked immunosorbent assay (ELISA) was used to find a specific cutoff value for the NPC-related seropositivity of EBV IgG antibodies.
RESULTS: NPC group showed higher serum level of EBV IgG antibodies than control and other HNCA groups (P < .05). However, the traditional cutoff value, mean + 2 SDs of control subjects, failed to demarcate the seropositives of NPC patients from those of healthy population (P > .05). The new cutoff value, mean + 2 SDs of the seropositives group of control subjects who had already been grouped by the traditional cutoff value, proved successful. It succeeded to demarcate between the NPC-related EBV IgG seropositivity and that issued from the persistent, latent, or reactivated EBV infection in the population (P < .05). The sensitivity/specificity of NPC detection by the new cutoff-based ELISA kit, 76.19% and 86%, was close or higher than that of EBV IgA antibodies.
CONCLUSION: EBV IgG-based ELISA could be used for the diagnosis of NPC using a new cutoff threshold that excludes the population baseline of EBV IgG seropositivity.
Introduction: Hepatitis C virus (HCV) infection is a serious health problem. It is a major contributor to end-stage liver disease. Worldwide, 1-8% of all pregnant women were infected. Women with viral hepatitis may be at an increased risk of pregnancy complications. There are several obstetrics intervention acts as risk factors, which are specific to women pertaining the HCV infection; anti-D immunoglobulin (Ig) therapy may be one of them. Our objectives were to estimate the prevalence of HCV antibodies (anti-HCV), RNA, and genotype distribution among women with anti-D Ig therapy. Materials and methods: A cross sectional study was conducted. A sample of 154 Rhesus negative (Rh - ve) pregnant women regardless of the anti-D Ig therapy was collected. Anti-HCV were tested using third generation enzyme immunoassay (EIA-3) and immunoblot assay (Lia Tek-111), subsequently. In addition, 89 serum samples were subjected to molecular analysis using RT-PCR and DNA enzyme immunoassay (DEIA) method for the detection of HCV-RNA and genotypes. Results: Anti-HCV, and HCV-RNA seroprevalence were significantly higher (17.1, 35.5%) among women with anti-D Ig than their counter group (6.4, 13.16%), p = .038, .018, respectively. Significant direct positive dose response correlation (r = 0.78, p = .005) had been seen between number of anti-D Ig therapy and anti-HCV seropositive rate. Anti-D Ig therapy act as a risk factor (odds ratio (OR) = 3.01, 95%CI: 1.01-8.9) especially from the third dose onward. Women with anti-D Ig therapy were at higher risk (3.6 times more) of positive HCV-RNA (OR =3.6, 95%CI =1.19-10.837). Genotype HCV-1b showed higher prevalent (52.9%) among the recipients of anti-D Ig therapy while genotype HCV-3a (6.6%) was the lowest. Conclusions: Our study showed that Anti-D immunoglobulin therapy acts as a risk factor for acquiring HCV infection. Screening for HCV should be recommended for all recipients of anti-D Ig. Not only HCV antibodies but HCV-RNA detection being recommended for the diagnosis of HCV infection. A brief rational: Pregnant women with HCV infection are at risk of adverse obstetric outcome. Anti-D Ig therapy may be a risk factor for HCV infection. Hence, we conducted a cross sectional study with the objectives to estimate the prevalence of HCV antibodies (anti-HCV), RNA, and genotype distribution among women with anti-D Ig therapy. We found that anti-HCV and HCV-RNA seroprevalence were significantly higher in women with anti-D Ig. In addition, women with anti-D Ig therapy were 3.6 times more at risk of positive HCV-RNA with genotype HCV-1b showed higher prevalence. Therefore, anti-D Ig therapy is a risk factor for acquiring HCV infection and we recommend screening for HCV for all recipients of anti-D Ig. In addition, the diagnosis of HCV infection, should be made with HCV antibodies and HCV-RNA detection.
Matched MeSH terms: Hepatitis C Antibodies/analysis
In connexion with the recent detection of cases of monkeypox in man in West and Central Africa, the frequency of monkeypox outbreaks in monkeys since 1958, when the disease was first recognized in captive animals, has been investigated. Special incidence surveys were made for this purpose. During the last 3 years, a serological survey has been conducted to find natural foci of monkeypox virus, and a total of 2 242 sera from monkeys of different species from various parts of Africa and Asia have been examined for poxvirus antibodies. The survey failed to detect any significant indication of poxvirus infections. The observations suggest that although a few human cases of monkeypox have been identified, monkeypox in the natural environment is not widespread and is perhaps localized in small areas.
Antibodies have been the workhorse for diagnostic immunohistochemistry to specifically interrogate the expression of certain protein to aid in histopathological diagnosis. This review introduces another dimension of histochemistry that employs aptamers as the core tool, the so-called aptahistochemistry. Aptamers are an emerging class of molecular recognition elements that could recapitulate the roles of antibodies. The many advantageous properties of aptamers suited for this diagnostic platform are scrutinized. An in-depth discussion on the technical aspects of aptahistochemistry is provided with close step-by-step comparison to the more familiarized immunohistochemical procedures, namely functionalization of the aptamer as a probe, antigen retrieval, optimization with emphasis on incubation parameters and visualization methods. This review offers rationales to overcome the anticipated challenges in transition from immunohistochemistry to aptahistochemistry, which is deemed feasible for an average diagnostic pathology laboratory.
Serum samples were obtained within 3 days of capture from 106 cynomolgus monkeys (Macaca fascicularis) in peninsular Malaysia. Fifty-two monkeys were trapped on the fringes of palm oil estates and 54 in dense primary jungle. Sera were tested for antibodies to hepatitis A virus (HAV) with a commercial radioimmunoassay. Twenty-four animals had detectable serum anti-HAV activity (6 of 52 from palm oil estate sites and 18 of 54 from primary jungle sites). Among monkeys at both sites, antibody prevalence was strongly correlated with animal weight: overall only four of 69 monkeys (6%) weighing less than 2.0 kg had serum anti-HAV antibodies, while 14 of 29 (48%) weighing 2.0 to 3.9 kg, and 6 of 8 (75%) weighing 4.0 kg or more, had serum anti-HAV antibodies. These data suggest that wild cynomolgus monkeys in Malaysian jungles become infected with HAV or an HAV-like virus at a rate comparable to that of humans in the same region, and raise the possibility of a sylvatic cycle for HAV.
The indirect hemagglutination test was used to study antibody titers to Entamoeba histolytica in different Malaysian populations. Eighty-seven percent of Orang Asli (western Malaysian aborigines) adults and 79% of Orang Asli children with acute amebic dysentery were seropositive. However, significantly fewer children (39%) with amebic dysentery had high titer responses (titer greater than or equal to 1:1,280) than did adults with amebic dysentery (76%). No correlation between proctoscopic severity and amebic titer was found. Forty-four percent of asymptomatic family members were seroresponders. Satak, an Orang Asli village located near towns, had significantly more seroresponders (32%) than did the isolated, deep jungle village, Belatim (4%).
Using ELISA and COPT diagnostic tests, serological evidence of Malaysian schistosomiasis was discovered among Orang Asli populations from three areas in Peninsular Malaysia. Serum samples collected in 1975 indicated an ELISA-positive prevalence of 25% and a COPT prevalence of 11% from Pos Iskandar, Pahang and an ELISA prevalence of 13% and a COPT of 4% from Bukit Lanjan, Selangor. Resurveys at these site in 1982-1984 showed a continued presence of serological positive individuals but prevalence rates were markedly lower: 7% and 1% for ELISA and 4% and 2% for COPT at Pos Iskandar and Bukit Lanjan respectively. Snail hosts were not found at either site. The source of infection for persons living in these lowland areas remains unknown. In a third area, Kuala Tahan, Pahang, located in the foothills of the central mountain range, foci of transmission have been found near to Orang Asli settlements. The serological prevalence rate among Negrito Orang Asli in that study area was 9% for ELISA and 4% for COPT. Thirty-three of 36 COPT-positive sera produced vacuolated bleb precipates and in 31 these were the only reactions seen. The high percentage of positives producing only these precipates suggests that among Orang Asli schistosomiasis patients such reactions are not an indication of recently acquired infection as has been reported for schistosomiasis patients in the Philippines.
A specific enzyme immunoassay (EIA) for the diagnosis of hepatitis C virus (HCV) infection was developed by recombinant DNA technology. Abbott HCV EIA was used to detect antibody to HCV (anti-HCV) in non-transfused and multiply-transfused thalassemia patients. None of 11 non-transfused patients had anti-HCV but 3 of 52 (5.8%) multiply-transfused patients had anti-HCV. This study showed that the prevalence rate of HCV infection is low in thalassemia patients. However, it is still important to identify hepatitis C virus infected patients in high risk groups because hepatitis C is associated with chronic hepatitis, cirrhosis and hepatocellular carcinoma.
Fifty medical students were screened for hepatitis B serological markers of whom 42 students entered the study. Those who were found to be negative for all markers were vaccinated with 1.0 ml (20 mcg HBsAg) Engerix-B vaccine intramuscularly in the deltoid region according to the 0, 1, 6 month schedule. Blood samples were taken at 1, 2, 3, 6, 9 months. One month following the first dose, 7% showed detectable AntiHBs with a GMT of 11 IU/I. By the sixth month, just before the third dose was given, 79% seroconverted with a GMT of 2952 IU/I. Three months following the third dose all had seroconverted with a GMT of 18,381 IU/I. No serious adverse reactions were noted and none of the subjects showed evidence of hepatitis B infection during the study. This study thus confirms the high immunogenicity and safety of recombinant yeast-extract hepatitis B vaccine.
Matched MeSH terms: Hepatitis B Antibodies/analysis
Rubella antibody rates in the female population of Kuala Lumpur were lower than those reported from temperate countries, though similar to rates found in other tropical countries excepting Singapore. Among the major ethnic groups, the immunity status of the Chinese was higher than that of the Malay and Indian groups.
The indirect fluorescence antibody technique has been employed to study the prevalence of toxoplasma antibodies in Singapore. 42.5% of clinically suspected cases of toxoplasmosis showed antibody titres. Of these, 17.5% had titres greater than or equal to 1.64. Malays and Indians have higher positive rates compared to the main ethnic group, the Chinese. Antibody titres are found in both males and females and span through the various age groups. The possible mode of transmission is discussed and the importance of congenital toxoplasmosis is indicated.
Blood samples from 1,600 persons who sought immunisation against hepatitis B in private clinics in Singapore in 1988-1989 were screened for two viral markers. Of that total, 4.81% were positive for HBsAg and 17.31% had anti-HBs levels greater than 10 mIU/ml, indicating that about 22.12% of the general population would not benefit from immunisation. Preimmunisation screening will identify persons not requiring the hepatitis B vaccine and thus, avoid wastage. When immunisation has already been performed without screening, recall for post-immunisation screening should be considered in order to detect the infectious hepatitis B carriers. Data in this study indicates that at this point in time, it is important to immunise adolescents and adults, in addition to neonates and children.
Matched MeSH terms: Hepatitis B Antibodies/analysis
Sera from 200 Malaysian male drug abusers were tested for markers of Hepatitis B virus (HBV) infection, viz. HBsAg, HBeAg, anti-HBs and anti-HBc using commercially available enzyme immunoassay (EIA) kits supplied by Abbot Laboratories, Chicago. Of these, 103 (51.5%) were positive for at least one HBV marker, 11 (5.5%) were positive for HBsAg; 4 (2%) for HBeAg, 74 (37%) for anti-HBs and 85 (42.5%) for anti-HBc. The HBsAg carrier rate was roughly the same as the carrier rate in the general population of Malaysia. The majority of drug abusers (95%) have had subclinical, asymptomatic HBV infection. Racially the Malay drug abusers had the highest exposure rate (54.2%). The HBsAg carrier rate was highest in the Chinese drug abusers (15.3%) and lowest in the Indians (0%). The mean age for the HBsAg carriers was found to be 26 years with a mean duration of drug abuse of 72 months. The Malaysian Anti-Narcotics Task Force of the National Security Council reported in the Malay Mail (July 13, 1985) that there were about 106,000 identified drug abusers in Malaysia and that 63% of these were in the 20-29 age groups. It appears from our study that this age group also coincides with the period of high HBsAg carrier rate. Age wise, those less than 21 years old had the highest HBsAg (11%) and HBeAg (5.6%) prevalence rates indicating high infectivity. After the age of 30 years, nearly 50% of the drug abusers appear to be immune with the HBe prevalence of 0%.(ABSTRACT TRUNCATED AT 250 WORDS)
Matched MeSH terms: Hepatitis B Antibodies/analysis*
The indirect hemagglutination test was used to measure malaria antibody levels in residents of an endemic area of Malaysia. Blood specimens were collected at 4-week intervals for a year. Seropositivity rates increased with age and number of episodes of malaria in young children. Although antibody levels were variable, titers tended to rise with parasitemia and fall in the absence of detected parasites. In general, the serologic indices tended to reflect the parasitologic findings.
A cohort of 62 persons living in a malaria-endemic area was examined by serology and by blood film 14 times over a 56-week period. Serologic responses (indirect hemagglutination test) of the group as a whole reflected the malaria transmission as determined by blood slide examination. The serologic responses of individuals showed titer changes that were not always consistent with blood slide results. The use of chloroquine may have modified the host's immune response.
The overall comparisons of habitats are given in (Table III). The habitats are arranged in order of extent of alterations by man, with the least disturbed at the top. The highest average blood isolation rates came from the least disturbed areas. The highest monthly maximal rickettsial isolation rates from blood and maximal prevalence rates of antibody per month were also obtained at Bukit Lanjan, the habitat least altered by activities of man. The lowest average blood isolation rate (6%) and the lowest monthly maximal rickettsial isolation and antibody prevalence rates were obtained at Bukit Mandol, the habitat most extensively and intensively altered by man. The intermediate habitats had intermediate rates. We caution anyone interpreting these observations, however, in terms of human disease, which seem to be associated with hyperendemic foci. Here we are not dealing with hyperendemicity from the standpoint of human disease, but present evidence of widespread endemicity from which hyperendemic foci may derive. Also, we have not yet identified the prevalent strains and do not know their infectivity to man.