Cytokine gene polymorphisms of TNFα, IL-6, IL-10, TGFß and IFNγ in the Saudi population.

Studies have demonstrated associations between cytokine gene polymorphisms and ethnicity. In the present work the authors examine polymorphisms in the genes encoding interleukin-6 (IL-6), IL-10, interferon-gamma (IFNgamma), tumour necrosis factor-alpha (TNFalpha) and transforming growth factor-beta (TGFbeta1) using the polymerase chain reaction sequence-specific primer (PCR-SSP) method in 150 healthy unrelated Saudis, and results compared with those from other studied populations. The genotype distributions were consistent with the Hardy-Weinberg equilibrium, and the genotype frequencies observed among Saudis showed both similarity and difference to other populations. The most notable difference was in the distribution of IL-6, where the Saudi population showed a lower CG genotype frequency compared with White American (22% vs. 39.2%, P = 0.004), Italian (22% vs. 50%, P < 0.0001) and Brazilian (22% vs. 40.8%, P < 0.0001) populations. The study population also showed a higher frequency of the IL-6 GG genotype compared with White Americans (72% vs. 45.1%, P < 0.0001), Italians (72% vs. 41%, P < 0.0001) and Brazilians (72% vs. 49.3%, P < 0.0001). These results may have significant clinical relevance to the understanding of prevalent diseases in Saudi Arabia.

Garlic and onion sensitization among Saudi patients screened for food allergy: a hospital based study.

BACKGROUND: Detection of specific IgE antibodies against food materials indicates allergic sensitization. Some very widely consumed foods materials such as garlic and onion have rarely been investigated for their allergenic potential. OBJECTIVES: To assess the presence of garlic and onion specific IgE antibodies in patients investigated for food allergy. METHODS: Radioallergosorbent test (RAST) results of 108 patients with clinical suspicion of food allergy who were specifically screened for garlic and onion specific IgE antibodies along with other food allergens were analyzed retrospectively at King Khalid University Hospital between January 2008 and April 2009. This group of patients included 73 males and 35 females with mean age 27+13.2 years. Estimation of garlic and onion specific IgE antibodies was performed by radioallergosorbent test (RAST) using Pharmacia ImmunoCAP 250 analyzer. RESULTS: Out of the 108 patients 15 (13.8%) had garlic and onion specific IgE antibodies in their sera. Garlic specific IgE antibodies with the RAST scores between one to four were present in 14 and onion specific IgE were detected in 13 patients. For garlic specific IgEs majority of patients (08) had RAST score of one (0.35-0.69 kU/L) and for onion specific IgE antibodies seven patients had RAST score of two (0.70-3.49 kU/L). Among these patients 12 (80%) were found to have coexisting specific IgE antibodies against garlic and onion. CONCLUSION: The presence of garlic and onion specific IgE antibodies in a sizeable number of patients indicate sensitization and allergenic potential of these food materials.

Human leucocyte antigens: their association with end-stage renal disease in Saudi patients awaiting transplantation.

Most patients with chronic renal failure develop end-stage renal disease (ESRD) that requires renal transplantation. This study investigates the possible associations between human leucocyte antigen (HLA) Class I and Class II molecules with ESRD. Genotyping data (HLA) obtained between 2005 and 2009 on 235 unrelated Saudi patients (147 males, 88 females; mean age: 58 +/- 7 years) with ESRD awaiting renal transplantation were assessed retrospectively at the King Khalid University Hospital. Data were compared with the results on 60 normal, healthy, unrelated Saudi individuals (37 males and 23 females; mean age: 51 +/- 5 years). HLA Class I and Class II antigens were detected by lymphocytotoxicity and a polymerase chain reaction (PCR) method using DNA sequence-specific primers. Although present in small numbers, HLA Cw2 was found in significantly fewer patients (n = 11; 4.68%) compared to normal subjects (n = 9; 15%) and was found to confer protection against ESRD (P = 0.005; relative risk [RR]: 3.594, 95% confidence interval [CI]: 1.415-9.126). Among the HLA Class II antigens, HLA DQB1*03(8) was detected more frequently in the patient group (n = 65; 27.6%) than in the normal controls (n = 9; 15%) and was positively associated with risk of ESRD (P = 0.04; RR: 0.462, 95% CI: 0.215-0.991). No significant differences were observed between the two groups in respect of HLA-A2, HLA-B50(21), HLA-B51(5) and HLA-Cw7 (HLA Class I), and HLA-DRB1*04, HLA-DRB1*07 and HLA-DQB1*02 (HLA Class II). Occurrence of the most frequent HLA alleles was no different between the ESRD group and the controls. The protective role of HLA-Cw2 and the marginal susceptibility associated with HLA-DQBI*03(8) for ESRD requires further investigation.

Location of secretory component on the Fc edge of dimeric IgA1 reveals insight into the role of secretory IgA1 in mucosal immunity.

Secretory immunoglobulin A (SIgA) is the most prevalent antibody in the human body and a first line of defense in mucosal immunity. We located secretory component (SC) relative to dimeric IgA1 (dIgA1) within the SIgA1 structure using the constrained modeling of solution scattering and analytical ultracentrifugation data. The extended solution structure of dIgA1 is largely preserved within SIgA1. From conformational searches of SC locations, the best-fit SC models within SIgA1 show that SC is extended along the outermost convex edge of the Fc dimer in dIgA1. The topology of our SIgA1 structure reveals that it is able to bind to one FcalphaRI receptor molecule. SC binding to the Fc dimer confers protection to SIgA1 by the masking of proteolytically susceptible surface sites from bacterial proteases in the harsh environment of the mucosa. The models support a "zipper-like" unfolding of SC upon dIgA1 in the formation and transportation of SIgA1 into the mucosa.