Polymorphic cytokine genotypes as markers of disease severity in adult periodontitis

The distributions of the bi-allelic interleukin-1beta+3953 and tumor necrosis factor-alpha-308 genotypes were determined in 20 patients with advanced adult periodontitis, 20 patients with plaque associated gingivitis, and 45 referent population subjects. A significant increase in IL-1beta+3953 allele 2 frequency was found in patients with advanced periodontitis compared to referent subjects (the Fisher exact test; p=0.013). Furthermore, the frequency of TNF-alpha-308 allele 1 was significantly greater in patients with advanced disease compared to those with plaque associated gingivitis (the Fisher exact test; p=0.014). No significant correlation was observed between genotype and cytokine production in these patient populations.     

Determination of hepatitis B virus subtypes by an enzyme immunoassay method using monoclonal antibodies to type-specific epitopes of HBsAg

We described a Hepatitis B surface antigen (HBsAg) subtyping method based on a commercial enzyme immunoassay (EIA) for detection of HBsAg in which the procedure was modified to include the use of monoclonal antibodies with restricted anti-HBs specificities. This method, which was able to classify HBsAg as: ayw1, ayw2, ayw3, ayw3 * (intermediate between ayw3 and ayw4 ), ayw4, ayr, adw2, adw4 and adr , was compared to counter electrophoresis procedure (CEP) by testing HBsAg positive sera from blood donors included in a prospective national epidemiological survey. Among the 256 HBsAg positive samples tested with both techniques, 111 (43.3%) could not be subtyped with CEP vs 10 (3.9%) with our modified EIA. This difference was related to the serum HBsAg concentration which must be greater than 3000 ng/mL and 100 ng/mL for CEP and EIA, respectively. The results obtained from 145 sera with both methods were concordant. Seventeen out of 18 samples partially classified as ay with CEP were completely determined with EIA.
This reliable procedure, derived from commercially available reagents, can be easily used in several applications such as large epidemiologic studies and as a substitute for nucleotide sequencing genotyping which is not adapted for large-scale screening and not applicable on samples from nonviremic hepatitis B virus (HBV) carriers.     

Association of malnutrition with amebiasis

Observation of a cohort of preschool children in Dhaka, Bangladesh, is beginning to reveal the contributions of environment, host, and parasite to amebiasis. Reviewed here are the associations and interactions of malnutrition, IgA and interferon-γ, human leukocyte antigen alleles, and parasite genotypes to the outcome of infection. Future efforts aimed at understanding the mechanisms of these effects are described.     

Allele‐specific antibodies to Plasmodium falciparum merozoite surface protein‐2 and protection against clinical malaria

IgG and IgG3 antibodies to merozoite surface protein‐2 (MSP‐2) of Plasmodium falciparum have been associated with protection from clinical malaria in independent studies. We determined whether this protection was allele‐specific by testing whether children who developed clinical malaria lacked IgG/IgG3 antibodies specific to the dominant msp2 parasite genotypes detected during clinical episodes. We analysed pre‐existing IgG and IgG1/IgG3 antibodies to antigens representing the major dimorphic types of MSP‐2 by ELISA. We used quantitative real‐time PCR to determine the dominant msp2 alleles in parasites detected in clinical episodes. Over half (55%, 80/146) of infections contained both allelic types. Single or dominant IC1‐ and FC27‐like alleles were detected in 46% and 42% of infections respectively, and both types were equally dominant in 12%. High levels of IgG/IgG3 antibodies to the FC27‐like antigen were not significantly associated with a lower likelihood of clinical episodes caused by parasites bearing FC27‐like compared to IC1‐like alleles, and vice versa for IgG/IgG3 antibodies to the IC1‐like antigen. These findings were supported by competition ELISAs which demonstrated the presence of IgG antibodies to allele‐specific epitopes within both antigens. Thus, even for this well‐studied antigen, the importance of an allele‐specific component of naturally acquired protective immunity to malaria remains to be confirmed.     

Transmission of hepatitis C virus among spouses in Cameroon and the Central African Republic

Heterosexual transmission of hepatitis C virus (HCV) is uncommon, with few studies undertaken in Central Africa. To determine the frequency of inter‐spouse HCV transmission, cross‐sectional studies of elderly individuals in Ebolowa, Cameroon and Nola, Central African Republic, in which, respectively, 24 and 83 long‐term couples had been identified, were examined further. Blood samples were tested for antibody to HCV. Anti‐HCV positive samples were genotyped by phylogenetic analysis of a fragment of the NS5B gene. In Nola, 4 out of 9 (44.4%) wives of anti‐HCV positive husbands and 1 out of 74 (1.4%) wives of anti‐HCV negative husbands were anti‐HCV positive (P < 0.001); in Ebolowa, the corresponding proportions were 10 out of 15 (66.7%) and 3 out of 9 (33.3%) (P = 0.21). After adjustment for age and site‐specific risk factors of HCV infection, HCV seropositivity of the wives remained associated with their husbands' HCV serostatus, significantly so in Nola (P = 0.003) and marginally in Ebolowa (P = 0.06). In 7 out of 14 concordant seropositive couples, the genotype could be determined in both spouses. Four couples were infected with different genotypes, while three were infected with the same genotype. Thus, serological concordance between the spouses was related to a combination of infections acquired independently and inter‐spouse transmission. It could not be determined whether inter‐spouse transmission occurred sexually, through blood–blood contact, or otherwise. Inter‐spouse transmission may have contributed to the high prevalence among elderly populations of Central Africa since some patients infected during healthcare subsequently transmitted the virus to their spouse. J. Med. Virol. 83:2113–2118, 2011. © 2011 Wiley Periodicals, Inc.     

A first report on the characterization of rotavirus strains in Sierra Leone

In an effort to reduce the high mortalities associated with rotavirus infections, a number of African countries are considering introducing human rotavirus vaccines. The demonstrated safety and efficacy of the live‐attenuate human rotavirus vaccines in several clinical trials worldwide has accelerated such initiatives. Although the percentage‐mortality rates for Sierra Leone are top of the list for rotavirus‐associated deaths in Africa, no study has reported the prevalent strains circulating within this country. In this study, stool specimens were collected from 128 Sierra Leonean children presenting with diarrhea in 2005. Almost 37.5% (48/128) were rotavirus positive by EIA, of which 89.6% (43/48) revealed a short electropherotype, and a further 6.98% (3/48) could not be assigned a PAGE pattern. Genotyping analysis revealed G2P[4] (30.23%), G2P[6] (13.95%), G8P[6] (11.63%), G2P[8] (4.65%), G8P[4] (4.65%), and G8P[8] (2%) strains. About 11% were only assigned VP7 genotypes (G2), while 20.9% had mixed G and P types. The frequent detection of G2 rotaviruses could be of concern considering data generated from some studies that suggests lower efficacy of Rotarix® vaccine against G2 rotaviruses. This underscores the need for extensive and continuous regional strain surveillance to support rotavirus vaccines introduction and guide future vaccine development efforts. Such information will be useful before considering administration of specific rotavirus vaccine candidates in countries like Sierra Leone where little is known about circulating rotavirus strains. J. Med. Virol. 83:540–550, 2011. © 2011 Wiley‐Liss, Inc.     

糖尿病足感染中耐甲氧西林表皮葡萄球菌SCCmec分型临床研究

目的 研究分离于糖尿病足感染(DFI)溃疡创面的耐甲氧西林表皮葡萄球菌(MRSE)的SCCmec分型特点及不同型别的耐药特征.方法 2008年1月-2010年6月从天津某医院390例DFI溃疡中分离出70株表皮葡萄球菌,提取细菌的DNA,用聚合酶链反应(PCR)方法检测mecA基因,并对MRSE进行SCCmec分型;采...     

Cryoglobulinaemia associated with hepatitis C virus: influence of HCV genotypes, HCV-RNA viraemia and HIV coinfection

To determine whether the clinical and immunological expression of patients with cryoglobulinaemia associated with chronic hepatitis C virus (HCV) infection varied according to HCV-RNA load, HCV genotype or human immunodeficiency virus (HIV) coinfection. We studied 340 HCV patients (188 women and 152 men, with a mean age of 49 years) consecutively diagnosed with cryoglobulinaemia between 1993 and 2003 in our hospital. HCV infection was confirmed by serum HCV-RNA determination in all patients. Two hundred and forty-eight (73%) patients had asymptomatic cryoglobulinaemia and 92 (27%) presented cryoglobulinaemic symptoms. Patients with genotype 1 had a higher mean age at diagnosis of cryoglobulinaemia (48.2 vs 40.2 yrs, P < 0.001) and a higher prevalence of cryoglobulinaemic symptoms (25%vs 10%, P = 0.02), especially of vasculitic features (19%vs 5%, P = 0.014). In comparison with monoinfected HCV patients, those with HIV coinfection had a lower mean age at diagnosis of cryoglobulinaemia (40.4 vs 52.8 years, P < 0.001), a lower prevalence of cryoglobulinaemic symptoms (15%vs 34%, P < 0.001), vasculitis (10%vs 28%, P < 0.001), associated systemic autoimmune disease (3%vs 14%, P = 0.001), rheumatoid factor (30%vs 70%, P = 0.001) and hypocomplementaemia (50%vs 78%, P = 0.01). In HCV-HIV patients, a high viral load was associated with a high frequency of symptomatic cryoglobulinaemia, especially in patients with a high viral load of the two viruses (50%vs 7%, P = 0.001) A higher frequency of cryoglobulinaemic symptoms (especially vasculitis) was found in patients with HCV monoinfection and in those carrying HCV genotype 1. In contrast, patients with HIV coinfection presented a threefold lower prevalence of vasculitis. Associated HIV infection significantly attenuated the clinical and immunological expression of cryoglobulinaemia, except in coinfected patients with high viral loads for the two viruses.