Effect of exposure to silica in inducing autoimmune hepatitis: an experimental animal-controlled study.

OBJECTIVE: The aim of this experimental study is to investigate the effect of subcutaneous and oral sodium silicate in inducing the autoimmune hepatitis. MATERIALS AND METHODS: Twelve Brown Norway rats were studied, six rats were challenged with Sodium Silicate and the rest were challenged with normal saline as a control group. At 14th week post-sodium silicate or normal saline exposure, the rats were sacrificed. Histopathological studies were conducted in six positive autoantibodies responding silicate group rats and then compared with an equal number of negative autoantibodies responding control rats. RESULTS: The liver findings from sodium silicate group of animals showed a histopathological reaction in 3/6 (50%) compared with 0/6 of the corresponding control saline group (p = 0.09). However, the absolute differences in the percentage between the two groups was 50%, the subcutaneous sodium silicate sub-group showed hepatic tissue response close to being statistically significant level (p = 0.05). CONCLUSIONS: After correlating the results with autoantibodies including serum antinuclear antibodies and anti ribo-nucleoprotein response of the same rats, it is concluded that sodium silicate play a role in inducing the autoimmune hepatitis in a genetically susceptible rat model.

Chironomid midges as a cause of allergy in the Sudan.

Hypersensitivity to Chironomidae (non-biting midges) has been a problem in the Sudan since about 1927 and appears to be due to increased breeding of a single chironomid species, Cladotanytarsus lewisi (Freeman). Mass emergence of the midges in thought to be related to the larval diet of algae and diatoms, the numbers of which are greatly enhanced by the retention of plant nutrients in lacustrine conditions resulting from interruption to the natural flow of the Nile by the construction of dams. Immunological studies in allergic individuals using an allergen extract prepared from C. lewisi indicate that the concentration of specific immunoglobulin E ("allergic antibody") directed against C. lewisi is raised in patients with established hypersensitivity to the midge but not in control subjects. The concentration of specific IgE is also related to the severity of clinical symptoms. These results indicate that this widespread and important "man made" hypersensitivity in the Sudan has the features of well recognized immediate-type allergy commonly associated with pollens and other air-borne allergens.

Evaluation of a Brucella enzyme immunoassay test (ELISA) in comparison with bacteriological culture and agglutination.

An ELISA test for IgG and IgM antibrucella antibodies was found to be effective in diagnosis of human brucellosis. Assays for IgG and IgM in 30 culture-positive cases gave significant ELISA values. By the standard agglutination test, 10% of these cases gave readings less than 1:160. These are considered insignificant, taking 1:160 as the accepted cut-off value. Moreover, in an extra 135 samples from suspected brucella cases, where only serology was requested (77.6% of all cases), 7.4% were found to have IgM brucella antibodies by ELISA. In all of these, the corresponding agglutination titres were less than 1:80 and hence reported as insignificant. We report the detection of IgG and IgM antibodies in samples from patients with both acute and chronic disease. In few patients with acute disease, only IgM was detected. These findings are discussed in comparison with earlier studies. Finally, the ELISA test, in addition to measuring antibody classes directly, also detects incomplete antibodies. By this, it can efficiently replace the 2 mercaptoethanol test (2ME) and the Coomb's antihuman-globulin test. This saves considerable laboratory cost and time.

Helicobacter pylori infection in children in Saudi Arabia.

20 children with suspected Helicobacter pylori (H. pylori) infection are presented. The mean age of the children was 9.4 years (range 4-13 years). The mean H. pylori IgG and IgA antibodies were 677 units and 760.7 units respectively. Antral biopsy cultures were positive in five children. Histopathology of the gastric antral and duodenal biopsies showed H. pylori gastritis in 11 children, duodenitis and gastritis in five, normal histology in three and one child had normal histology with H. pylori like organism on the surface of the antral mucosa. From this study, we conclude that serology is a good diagnostic test for H. pylori infection in Saudi Arabia.

Comparison of Helicobacter pylori antibody levels in children in Riyadh.

Helicobacter pylori (H. pylori) antibodies were determined in 229 asymptomatic children and 43 symptomatic children in Saudi Arabia. There is a significant difference in IgG and IgA antibodies for both asymptomatic and symptomatic children (p = 0.00001). We conclude that Helicobacter pylori antibody determination by ELISA is a good screening test for diagnosis of Helicobacter pylori infection in children in Saudi Arabia.

Respiratory and allergic disorders in workers exposed to grain and flour dusts.

Symptoms suggestive of chronic bronchitis or chronic productive cough were found in 29.0% of 100 workers exposed to flour dust in a flour mill, 26.0% presenting with chronic cough and 29.0% with phlegm. In the control group, the prevalence of chronic cough and phlegm was only 6.6% in each category. While 22.0% of the workers complained of chest tightness on exposure, and 18.0% developed symptoms and signs of bronchial asthma, only 3.3% of the controls complained of chest tightness and 3.3% of asthma. Respiratory measurements before and after the working shift showed a significant drop (p less than .001) in the forced expiratory volume in 1 sec (FEV1.0) and forced vital capacity (FVC) in the exposed group. Fifty-eight percent of the exposed workers experienced a drop in FEV1.0 and FVC measurements. A positive skin reaction to wheat flour extract was recorded among 31% of the exposed workers vs. 10% of the controls. The prevalence of other associated allergic symptoms was 17.0% and 19.0% for sinusitis and conjunctivitis, respectively; in the unexposed group, the prevalence of the same symptoms ranged between 3.3% and 6.6%. A strong association was revealed between exposure to grain and flour dusts and the prevalence of respiratory and allergic disorders.

Peanut allergy: The frequency of sensitization to peanut allergen in patients with allergic disease.

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A study of clinical and allergic aspects of rhinitis patients in Riyadh.

Eighty consecutive patients presenting with variable nasal symptoms were investigated. Fifty-three (66.25%) were identified as allergic and 27 (33.5%) as having nonallergic rhinitis. Medical history and clinical examination alone seemed to be inadequate in establishing a diagnosis, since the main complaints, i.e., nasal itching, sneezing and runny rose, occurred with the same frequency in both groups. However, alternating nasal blockage and sneezing were prominent in the allergic group (80.40%), while perennial symptoms were more evident in the nonallergic group (68%). There were no striking differences between the two groups in the occurrence of nasal septal deviation or in evidence of nasal polyps. In the allergic groups, sensitivities to indoor allergens, i.e., cockroaches, cat fur, house dust, as well as to pollens, were very prominent. Among the nonspecific provoking factors, dust, strong smells, smoke and stress seem to be important.

Overwhelming respiratory failure associated with Legionella pneumophila.

Four patients were admitted to the medical intensive care unit at King Khalid University Hospital (KKUH) with overwhelming respiratory failure. Extensive investigations revealed serological evidence of Legionella infection. Three patients required intubation and mechanical ventilation. All patients received erythromycin; rifampin was added to two patients. Two patients survived and two patients died. We report, for the first time in Saudi Arabia, four cases of Legionella pneumophila with severe respiratory failure.

A comparative study of immediate skin test reactivity to inhalant allergens in asthmatic children of two different regions in Saudi Arabia.

The skin test reactivities to various inhalant allergens in asthmatic children from two different regions in Saudi Arabia were compared. One hundred-twenty subjects each from the Central and Western regions, representing different environmental features, were selected. Prick test reactivity to 24 common allergens were analyzed and compared. Seventy-one (59.2%) patients from Riyadh (Central region) showed positive skin reactions to one or more allergens, while 87 (72.5%) reacted positively to different allergens from Makkah (Western region). The distribution of skin test sensitivity revealed striking differences in the two groups. The most prominent were reactions to the house dust mite (D. farinae) which amounted to 56.3% and to fungal allergens, 31.3% in asthmatics from the Western region, while reactions to the same allergens in subjects from the Central region were 10% and 5.8%, respectively. Similarly, marked variations were noted with pollen grain allergens with 9.3% in Central region and 15.4% in the Western region. The study indicates the presence of different allergen profiles in the two regions and suggests the influence of climatic and environmental factors and their impact on sensitization of susceptible subjects.

Airborne Alternaria spores: Potential allergic sensitizers in Saudi Arabia.

BACKGROUND: In order to investigate the role of airborne Alternaria spp. in the sensitization of individuals having respiratory allergy symptoms, particularly bronchial asthma, an aerobiologic and clinical (diagnostic) study was conducted at several centers in Saudi Arabia. MATERIALS AND METHODS: Airborne Alternaria spores were studied at four different centers in Riyadh, Jeddah and Al-Khobar, including three years at one site. Skin prick tests (SPT) were conducted on a total of 616 allergic individuals attending allergy clinics at six different hospitals in Abha, Qassim, Gizan, Jeddah, Hofuf and Makkah regions. RESULTS: Alternaria spores constituted between 1.9%-9.6% of the total fungal air spora, and the maximum concentration exceeded 5x10 2 spores per m3 of air in Jeddah, followed by 4.9x102 spores per m3 in Al-Khobar. Mean weekly and monthly concentration of Alternaria fluctuated, reaching up to 150 spores per m 3 and 60 spores per m 3, respectively. Quantitative regional variations were also recorded. IgE-mediated SPT reactivities conducted on allergic patients resulted in an overall 21.6% positive reactions, showing mild, moderate and strong wheal and erythema. CONCLUSION: The findings reveal that Alternaria spores are prevalent as a major component in the outdoor environment of the Kingdom, with peaks in April and October. The overall 21.6% positive SPT reactions indicate the sensitization level or cross-reactive sensitivity to Alternaria allergens. The study suggests that airborne Alternaria can be a potential allergic sensitizer in susceptible individuals and can be a risk factor in sensitized individuals with symptoms of bronchial asthma and allergic rhinitis in the Kingdom of Saudi Arabia.

Cladosporium as an airborne allergen in Saudi Arabia.

Airborne mold monitoring in three cities in Saudi Arabia has documented the presence of Cladosporium in high concentrations. The spore counts reached threshold levels for sensitization at Jeddah and Al-Khobar with prominent seasonal variations. The concentration in Riyadh (central region) showed levels with minor fluctuationgs and a minor peak towards the month of Novermber. Indoor monitoring also revealed the presence of Cladosporium. Ten species of Cladosporium were idenified with C. sphaerospermum, C. herbarum, C. cladosporoides and C. macrocarpum being most prevalent. The species are relevant in relation to extracts for diagnosis. Skin testing of asthmatic children in Riyadh and Makkah revealed reactivities to Cladosporium extract of 5.8% and 31.3%, respectively. This indicates that Cladosporium may be an important allergen in the region that necessitates further biochemical and immunochemical studies to confirm the allergic impact of the species of Cladosporium prevalent in the region.

House dust mite allergens in Saudi Arabia: Regional variations and immune response.

In order to assess the causative extrinsic allergic factor(s) in school-age children diagnosed as having bronchial asthma and allergic rhinitis, and to qualitatively and quantitatively evaluate the presence of house dust mites (HDMs) in the homes of these children in Saudi Arabia, a study analyzing mite contents in 165 samples collected from patientsâ indoor environment was conducted. The dust samples were collected from four regions of Saudi Arabia, showing variation in their geography and climate. Immunochemical assays were performed using ALK reagents by ELISA technique. A total of 462 children were also tested using skin prick test (SPT) method for IgE-mediated reactions to HDMs. The samples from the Central dry region revealed a very low amount of the potent house dust mites (Dermatophagoides pteronyssinus and D. farinae, the two dominant species in various parts of the world). The samples from the Southern mountainous region contained a very high concentration of Der p I (84,000 ng/g of dust), while the Western coastal region showed a high concentration of Der f I (up to 22,000 ng/g). The mid-Western agricultural region did not exhibit any significant level of either Der p I or Der f I. The maximum level of D. pteronyssinus detected in the Central dry region was 106 ng/g of dust. The data exhibit both qualitative and quantitative variations of HDMs in the three regions and may be attributed to variation in geography and climate, particularly humidity of the regions, which vary significantly. Riyadh in the Central region is considered to have low humidity (<40%), while humidity in the Western coastal region, Jeddah, and the Southern region of Abha is comparatively higher, which helps house dust mites thrive. SPT results in these regions with house dust mite allergens (in addition to other common inhalant allergens) also revealed a considerable number of IgE-mediated reactions, consistent with the frequency of house dust mites in the region. Though more data are being accumulated on the subject to conduct a statistical comparison and more skin tests are underway in the Southern region, the study suggests the presence of at least two HDMs as well as qualitative diversity and quantitative variation of house dust mites in Saudi Arabia. The study also indicates, with a considerable number of IgE-mediated reactions, the possible influence of mites in the allergic manifestations of many patients, which is not only common, but increasing in parts of the country.

Human sensitization to Prosopis juliflora antigen in Saudi Arabia.

BACKGROUND: Allergenicity to Prosopis juliflora pollen antigen has been reported from only a few countries, including the US, South Africa, India and Kuwait. In some parts of Saudi Arabia, species of Prosopis have been introduced by the millions as roadside ornamentation. There appear to be four flowering seasons during which pollen grains float in all directions. However, the role of Prosopis pollen as the sensitizing and/or triggering agent of allergic asthma and/or rhinitis in the Kingdom has never been evaluated. PATIENTS AND METHODS: A total of 473 allergic patients suffering from bronchial asthma in four different geographical regions (Abha, Qassim, Hofuf and Gizan), and attending allergy clinics and chest disease centers of university and Ministry of Health hospitals in the region were tested for immediate hypersensitivity reaction to Prosopis juliflora allergens. Airborne pollen grains at one center were also studied for one full year, using volumetric sampling techniques. RESULTS: A total of 76.1% patients in Qassim, 37.5% in Gizan, 29% in Abha and 11% in Hofuf reacted positively to Prosopis antigen. Multiple sensitivities to other pollen antigens were detected in all patients. The level of airborne Prosopis pollen detected in Gizan exceeded 90 grains m -3 of air. CONCLUSION: In view of the documented evidence of Prosopis-involved allergenicity, the role of Prosopis pollen as a sensitizing factor in Saudi Arabia has been confirmed. However, the cause of elicitation of symptoms in many multiple sensitive patients, together with the question of cross-reactivities, needs thorough and detailed investigation. In vitro confirmation of all positive results is also required to incriminate Prosopis as one of the major allergens in parts of Saudi Arabia.

Sensitization to indigenous pollen and molds and other outdoor and indoor allergens in allergic patients from saudi arabia, United arab emirates, and Sudan.

BACKGROUND: : Airborne allergens vary from one climatic region to another. Therefore, it is important to analyze the environment of the region to select the most prevalent allergens for the diagnosis and treatment of allergic patients. OBJECTIVE: : To evaluate the prevalence of positive skin tests to pollen and fungal allergens collected from local indigenous plants or isolated molds, as well as other outdoor and indoor allergens in allergic patients in 6 different geographical areas in the Kingdom of Saudi Arabia (KSA), the United Arab Emirates, and Sudan. MATERIAL AND METHODS: : Four hundred ninety-two consecutive patients evaluated at different Allergy Clinics (276 women and 256 men; mean age, 30 years) participated in this study. The selection of indigenous allergens was based on research findings in different areas from Riyadh and adjoining areas. Indigenous raw material for pollen grains was collected from the desert near the capital city of Riyadh, KSA. The following plants were included: Chenopodium murale, Salsola imbricata, Rumex vesicarius, Ricinus communis, Artiplex nummularia, Amaranthus viridis, Artemisia monosperma, Plantago boissieri, and Prosopis juliflora. Indigenous molds were isolated from air sampling in Riyadh and grown to obtain the raw material. These included the following: Ulocladium spp., Penicillium spp., Aspergillus fumigatus, Cladosporium spp., and Alternaria spp. The raw material was processed under Good Manufacturing Practices for skin testing. Other commercially available outdoor (grass and tree pollens) and indoor (mites, cockroach, and cat dander) allergens were also tested. RESULTS: : The highest sensitization to indigenous pollens was detected to C. murale (32%) in Khartoum (Sudan) and S. imbricata (30%) and P. juliflora (24%) in the Riyadh region. The highest sensitization to molds was detected in Khartoum, especially to Cladosporium spp. (42%), Aspergillus (40%), and Alternaria spp. (38%). Sensitization to mites was also very prevalent in Khartoum (72%), as well as in Abu Dhabi (United Arab Emirates) (46%) and Jeddah (KSA) (30%). CONCLUSIONS: : The allergenicity of several indigenous pollens and molds derived from autochthonous sources was demonstrated. Prevalence studies in different regions of KSA and neighbor countries indicate different sensitization rates to these and other outdoor and indoor allergens.

Induction of autoimmunity in Brown Norway rats by oral and parenteral administration of sodium silicate.

Silica and silicate may disturb immune function such as autoimmunity and tumour immunity. The main objective of this study was to examine the relation between sodium silicate and induction of autoimmunity in genetically susceptible rats. In this study, thirty Brown Norway rats were randomised into four treatment groups, the first and second group receiving 3 mg of sodium silicate (NaSiO(4)) (equivalent to 2 mg silica) in 0.2 mL of normal saline either per oral or subcutaneously, and the third and fourth group (control) receiving 0.2 mL of normal saline (0.9%) through the same corresponding route. A significant number of rats (80%) (P < 0.05) which received sodium silicate by the subcutaneous route showed a high level of serum ANA compared with controls. In the oral, sodium silicate group showed high serum ANA in an insignificant number of rats. Other autoantibodies in both groups (anti-dsDNA, anti-Smith, anti-SSA, anti-SSB) showed gradual increased post exposure, but the numbers of rats with positive titres post exposure was statistically not significant. Silica exposure in rats appears to induce the development of autoimmunity. A longer duration post exposure to silicate seems to be associated with greater risks.

Allergic contact dermatitis: clinical features and profile of sensitizing allergens in Riyadh, Saudi Arabia.

BACKGROUND: No reports are available on allergic contact dermatitis in Saudi Arabia, although it seems to be a common skin problem. We attempted to explore certain clinical aspects in addition to the profile of sensitizing allergens in our area. As no standard panel for patch testing is available in our geographic region, we examined the suitability of the European Standard Series. METHODS: Patch testing was performed on 271 consecutive patients with various forms of dermititis, referred for evaluation of possible allergic contact dermatitis. The study included 147 women and 124 men. The patients were between 12 and 75 years of age. RESULTS: Out of 271 subjects, 152 (56.1%) showed one or more positive reactions. Of these, 80 (52.6%) were women and 72 (47.4%) were men. Almost one quarter of the patients (25.7%) presented with hand dermatitis. Positive reactions to 21 out of the 22 allergens were found. Sensitization was most common to nickel sulfate (39.5%), potassium dichromate (32.9%), and cobalt chloride (30.9%). Reactions to the other allergens ranged between 14.5% and 1.3%). Less than one percent of the patients (0.66%) reacted to benzocaine and showed no reaction to primin. CONCLUSIONS: Allergic contact dermatitis is a common skin problem in Saudi Arabia. Further studies that address the prevalence and incidence of the disease are indicated. The European Standard Series is suitable for patch testing patients in our community; however, we suggest exclusion of benzocaine and primin. The addition of three allergens of local relevance, black seed oil, local perfume mix, and henna, are presented and discussed. The formulation of a regional standard series for patch testing dermatitis patients in our geographic area requires further collaborative studies.

Immediate-type skin reactivity to extracts of the 'green nimitti' midge, (Cladotanytarsus lewisi), and other chironomids in asthmatic subjects in the Sudan and Egypt.

Skin 'prick' tests with an extract of the 'green nimitti' midge, Cladotanytarsus lewisi (Freeman), a potent airborne allergen associated with asthma and rhinitis in the Khartoum area, were undertaken on asthmatic subjects in several localities in the Sudan and Egypt in order to provide further information on the extent of this allergic problem. In the Sudan skin-test-positive individuals were identified in the Khartoum area, Kosti, Sennar, Wad Medani, Shendi and Atbara, and in Egypt at Aswan, Luxor and Qena. A number of asthmatic individuals giving a positive reaction to C. lewisi were also tested with extracts of seven sub-dominant species of Nilotic Chironomidae. There appeared to be a limited degree of cross-reactivity with these species, particularly Dicrotendipes fusconotatus (Kieffer), Procladius noctivagus (Kieffer) and Conchapelopia cygnus (Kieffer). The numbers of C. lewisi sensitive subjects giving positive skin-tests to these other species were ten out of 20, 12 out of 28 and 12 out of 29 respectively. In contrast, only five out of 31 reacted to Paracladopelma graminicolor (Kieffer), five out of 24 to Cladotanytarsus pseudomancus (Goetghebuer), three out of 32 to Nanocladius vitellinus (Kieffer) and two out of 28 to Cryptochironomus neonilicola (Freeman). These results indicate that Cladotanytarsus lewisi is a major source of chironomid allergen(s) in these asthmatic subjects and that hypersensitivity to C. lewisi is probably far more widespread than originally envisaged.

Age-related changes in blood lymphocyte subsets of Saudi Arabian healthy children.

The age-related changes in absolute and percentage values of lymphocyte subsets in the peripheral blood of healthy children of different ages (1 month to 13 years) were studied by flow cytometry. The absolute and percentage values for most lymphocyte subpopulations differed substantially with age. Comparisons among age groups from infants through adults revealed progressive declines in the absolute numbers of leukocytes, total lymphocytes, and T, B, and natural killer (NK) cells. The percentages of T cells increased with age. Within the T-lymphocyte population, the CD8(+) subset increased but the CD4(+) subset decreased, resulting in a declining CD4(+)/CD8(+) ratio. The percentage of B cells declined, but that of NK cells remained unchanged. The percentage of HLA-DR+ T cells increased over time, but their number changed inconsistently. Our findings confirm and extend earlier reports on age-related changes in lymphocyte subpopulations. These data should be useful in the interpretation of disease-related changes, as well as therapy-dependent alterations, in lymphocyte subsets in children of different age groups.

Increased prevalence of asthma in Saudi Arabia.

BACKGROUND: Bronchial asthma is among the most common chronic illnesses of childhood. A number of reports in the recent past suggest that the prevalence of asthma is increasing globally. OBJECTIVE: To investigate the changing prevalence of asthma in the Kingdom of Saudi Arabia. SUBJECTS AND METHODS: Two populations of schoolchildren between the ages of 8 and 16 years were studied using an internationally designed protocol in 1986 and 1995. The questionnaire used in these studies was very similar to the one used in the International Study of Allergy and Asthma in Childhood. A total of 2,123 school-children in 1986 (Jeddah and Riyadh) and 1,008 schoolchildren in 1995 (Hail and Gizan) were enrolled in the surveys. These cross-sectional studies of randomly selected schoolchildren were statistically analyzed using ANOVA and a Z test. RESULTS: The comparison of data between Riyadh versus Hail (inland desert dry environment) and Jeddah versus Gizan (coastal humid environment) revealed that the prevalence of asthma in the similar populations increased significantly from 8% in 1986 to 23% in 1995 (P < .0001). Likewise, the prevalence of allergic rhinitis also increased from 20% to 25% (P < .003) since 1986. However, no significant change in the prevalence of eczema (from 12% to 13%) was noted between 1986 and 1995. CONCLUSIONS: The study indicates that there was a significant increase in the prevalence of bronchial asthma and, to a lesser extent, in the prevalence of allergic rhinitis in the Kingdom of Saudi Arabia during this 9-year period. The study also revealed increased exposure to environmental factors such as tobacco smoke and indoor animals in Saudi houses. It seems that the continuing changes in contemporary life may well have contributed to the increased prevalence of asthma in the country.