Antibody responses to P. falciparum Apical Membrane Antigen 1(AMA-1) in relation to haemoglobin S (HbS), HbC, G6PD and ABO blood groups among Fulani and Masaleit living in Western Sudan.

Fulani and Masaleit are two sympatric ethnic groups in western Sudan who are characterised by marked differences in susceptibility to Plasmodium falciparum malaria. It has been demonstrated that Glucose-6-phosphate dehydrogenase (G6PD) deficiency and Sickle cell trait HbAS carriers are protected from the most severe forms of malaria. This study aimed to investigate a set of specific IgG subclasses against P. falciparum Apical Membrane Antigen 1 (AMA-1 3D7), haemoglobin variants and (G6PD) in association with malaria susceptibility among Fulani ethnic group compared to sympatric ethnic group living in Western Sudan. A total of 124 children aged 5-9 years from each tribe living in an area of hyper-endemic P. falciparum unstable malaria transmission were recruited and genotyped for the haemoglobin (Hb) genes, (G6PD) and (ABO) blood groups. Furthermore, the level of plasma IgG antibody subclasses against P. falciparum antigen (AMA-1) were measured using enzyme linked immunosorbent assays (ELISA). Higher levels of anti-malarial IgG1, IgG2 and IgG3 but not IgG4 antibody were found in Fulani when compared to Masaleit. Individuals carrying the HbCC phenotype were significantly associated with higher levels of IgG1 and IgG2. Furthermore, individuals having the HbAS phenotype were associated with higher levels of specific IgG2 and IgG4 antibodies. In addition, patients with G6PD A/A genotype were associated with higher levels of specific IgG2 antibody compared with those carrying the A/G and G/G genotypes. The results indicate that the Fulani ethnic group show lower frequency of HbAS, HbSS and HbAC compared to the Masaleit ethnic group. The inter-ethnic analysis shows no statistically significant difference in G6PD genotypes (P value = 0.791). However, the intra-ethnic analysis indicates that both ethnic groups have less A/A genotypes and (A) allele frequency of G6PD compared to G/G genotypes, while the HbSA genotype was associated with higher levels of IgG2 (AMA-1) and IgG4 antibodies. In addition, patients carrying the G6PD A/A genotype were associated with higher levels of specific IgG2 antibody compared with those carrying the A/G and G/G genotypes. The present results revealed that the Fulani ethnic group has statistically significantly lower frequency of abnormal haemoglobin resistant to malaria infection compared to the Masaleit ethnic group.

Seroprevalence of celiac disease among United Arab Emirates healthy adult nationals: a gender disparity.

AIM: To determine celiac disease (CD) prevalence and associated manifestations or risk factors in healthy adult Emiratis. METHODS: It is a cross-sectional prospective study, recruiting 1197 (573 women and 624 men) healthy Emiratis between September 2007 and April 2008 among those who went to Al Ain Hospital to undertake the prenuptial examination. Test for anti-tissue transglutaminase (tTG) IgA antibodies was used for CD diagnosis. Subjects with positive results in the anti tTG antibodies assay were also tested for anti-endomysial (EMA) IgA antibodies. A structured interview was used to collect basic demographic and clinical recall data including: information on name, contact address, age, gender, education status, previous diagnosis of CD, diagnosis of CD in 1(st) degree relatives and history of "chronic diarrhea, anemia, headache, hepatitis, diabetes, tumor, and thyroid disorder". RESULTS: Fourteen blood samples (1.17%; 14/1197) were seropositive for CD. The latent CD seropositive patients were 13 women and 1 man and therefore the seroprevalence of CD was 1:86 (14/1197) for adult Emiratis: 1:44 (13/573) for women and 1:624 for men. Binary logistic regression revealed that history of chronic anemia (crude OR = 7.09; 95%CI: 2.32-21.61; P = 0.003) and being a woman (OR = 14.46; 95%CI: 1.89-110.91; P = 0.001) were associated with CD seropositivity. Whereas, the thyroid disorder showed a positive association with CD seropositivity that approach statistical significance (OR = 11.30; 95%CI: 1.32-96.95; P = 0.09) and therefore was included in the multiple logistic regression analysis, which showed that CD seropositivity is independently associated only with history of chronic anemia (OR = 4.58; 95%CI: 1.45-14.48; P = 0.01) and being a woman person (OR = 10.47; 95%CI: 1.33-82.14; P = 0.026). CONCLUSION: Compared to men the CD seroprevalence among women was remarkably higher. The CD association with women and chronic anemia is of importance from a public health perspective.

Seroprevalence of antibodies to repetitive domains of Plasmodium vivax circumsporozoite protein in United Arab Emirates children.

The aim of this study was to determine the exposure of child citizens of the United Arab Emirates (UAE) to Plasmodium vivax, and to elucidate if it was related to place of residence or previous international travel to malaria-endemic areas. Blood samples were collected from 1010 primary schoolchildren resident in 7 out of 9 districts of the UAE during October and November 1999. Plasma samples were tested for antibodies against MAP4 (DGQPAGDR)3P2P30, a multiple antigen peptide containing the repeat amino acid sequences of P. vivax circumsporozoite protein (CSP), conjugated to 2 T-helper epitopes, P2 (QYIKANSKFIGITE) and P30 (FNNFTVSFWLRVPKVSASHLE) from tetanus toxin. For confirmation of P. vivax-specific reactivity, positive samples were further tested against (AGDR)6, a synthetic peptide containing 6 copies of a protective epitope within the CSP, and against a recombinant CSP, designated as NS1(81)V20. Results indicated that 3.3% of the children were seropositive. The seropositivity rates differed significantly in relation to place of residence, whereas travel outside the UAE did not significantly affect the exposure rates to P. vivax.

Protein G ELISA for detection of antibodies against Toxoplasma SAG1 in dromedaries.

ELISA was used for detection of antibodies against the immunodominant surface antigen 1 (SAG1, synonymous P30) of Toxoplasma gondii, and peroxidase-conjugated protein G was used instead of commercially unavailable enzyme-conjugated anti-dromedary antibody. A latex agglutination test was employed to select 20 seronegative control animals, and peroxidase-conjugated protein A was used for comparison with protein G. The overall seroprevalence rate was 31.4%; males had to some extent higher seropositive rate than females (P = 0.077). Seropositive camels sampled in winter had significantly higher-antibody levels than those sampled in summer (P < 0.01). ELISA values using protein G and protein A conjugates were significantly correlated (Spearman's rho = 0.797; n = 185; P < 0.001). The results were discussed.