Interleukin 13 receptors as biochemical markers in atopic patients.

BACKGROUND: Interleukin (IL) 13, a type 2 helper T cell (T(H)2), is an important regulator of inflammatory immune responses. It mediates its action through a receptor complex consisting of IL-13Ralpha1 and IL-4Ralpha. IL-13Ralpha2 binds IL-13 with high affinity and is thought to act primarily as a decoy receptor, sequestering IL-13 and thus inhibiting its action. Our aim was to clarify the role of these receptors in the diagnosis and follow-up of atopic patients. METHODS: We genotyped the 1398A>G polymorphism in the IL-13Ralpha1 gene using restriction fragment length polymorphism for causal genetic diversity and measured serum levels of IL-13Ralpha2 in 105 atopic patients suffering from atopic asthma, atopic dermatitis, and atopic rhinitis (35 each). We compared the results with those of 35 nonatopic control individuals. Total immunoglobulin (Ig) E and serum IL-13Ralpha2 were measured using enzyme-linked immunosorbent assay, and the eosinophil counts were recorded. RESULTS: A significant increase in serum IL-13Ralpha2 levels was recorded in the 3 atopic groups compared with the control group (P < .001), as well as a significant increase in total IgE levels and eosinophil counts. No significant association was found between 1398A>G and atopy other than a suggestive association between this polymorphism and raised total serum IgE levels in all 3 atopic groups (P < .001). CONCLUSIONS: These findings indicate that IL-13Ralpha2 plays an important role in atopy and that increased levels in different groups highlight its regulatory role in the development of atopic symptoms. The 1398A>G polymorphism might be involved in the production of IgE.

Interferon gamma gene polymorphism as a biochemical marker in Egyptian atopic patients.

OBJECTIVES: The aim of this study was to clarify the role of interferon (IFN) gamma in the diagnosis and follow-up of atopic patients. We genotyped the IFN-gamma polymorphism at position +874 to examine the relationship between serum levels of IFN-gamma and disease severity and the role of IFN-gamma as a biochemical and immunologic marker. METHODS: The study population comprised 75 patients suffering from atopic asthma, atopic dermatitis, and allergic rhinitis (25 each), and 25 control participants. Total immunoglobulin (Ig) E and serum IFN-gamma were measured by enzyme-linked immunosorbent assay, the IFN-gamma polymorphism at position +874 was determined by amplification refractory mutation system-polymerase chain reaction, and eosinophil counts were recorded. RESULTS: There was a significant association between genotype and the frequency of the A allele of the +874T/A polymorphism in atopic patients when compared with controls (P < .001). In all 3 groups, there was a significant increase in total IgE levels and eosinophil counts, and a decrease in serum IFN-gamma levels towards the presence of homozygous AA compared with homozygous TT. CONCLUSIONS: The IFN-gamma gene polymorphism at position +874 contributes to susceptibility to atopic diseases by decreasing the amount of IFN-gamma. Identification of variants of IFN-gamma gene signalling and its role in the development of atopic diseases provides a focus for the development of novel diagnostic and therapeutic strategies for these diseases.

Serodiagnosis of cystic echinococcosis in naturally infected camels.

An ELISA was developed for serological detection of Echinococcus granulosus infection in dromedary camels. Antigen B (AgB) partially purified from hydatid cyst fluid of camels or sheep naturally infected with cystic echinococcosis (CE) due to E. granulosus, as well as a recombinant antigen B product (r-AgB) were used in an ELISA to screen panels of serum samples from slaughtered camels naturally infected with CE. Native hydatid cyst fluid antigen preparations were able to detect antibodies in sera from a significant proportion of camels with CE, as confirmed at post-mortem. Seroreactivity however, was variable. ELISA specificity for sera from naturally infected camels versus inspection-negative animals ranged from 90 to 99%. Native antigen B gave the highest sensitivity (97%) in ELISA for camel CE confirmed at slaughter. In contrast, r-AgB gave lower sensitivity for camel (84%) and sheep (28%) CE. The r-AgB-ELISA was, however, highly specific (90 and 95%) respectively for both camel and sheep natural CE infection. These results indicate that an ELISA based on serum antibody detection to AgB could be developed for immunodiagnosis of cystic echinococcosis in camels.

Prevalence of cystic echinococcosis in camels (Camelus dromedarius) in Libya.

In an abattoir study, 514 camels, slaughtered for meat production in different areas of northern Libya were examined for the presence of cystic echinococcosis (CE). In addition, 367 sheep and 184 goats were examined. The overall prevalence of infection with CE was 48% in camels, 15.8% in sheep and 3.8% in goats. The infection rate, number and size of cysts were significantly higher in older camels. In six city abattoirs across northern Libya, i.e. Zawia, Tripoli, El-Khumes, Mesurata, Sirt and Benghazi, the prevalence rate of infection in camels ranged from 38.7% to 55.2%, in comparison with sheep and goat rates which were between 0% and 37.9% and 0% and 8.2%, respectively. In camels, the lungs were the most frequently infected organs (85.4%) with liver cysts occurring at a significantly lower rate (33%). In contrast, the liver was the predominant infected site with prevalence values of 86% and 100% in sheep and goats, respectively. More than 90% of camel hydatid cysts were fertile. The possible role of camels in the transmission of CE in Libya is discussed.

Echinococcus granulosus antigen B and seroreactivity in natural ovine hydatidosis.

Hydatid cyst fluid from sheep and camels infected with Echinococcus granulosus, together with partially purified preparations of hydatid fluid antigen B and a recombinant antigen B product, were tested in an ELISA for their ability to detect IgG antibodies against E granulosus in the serum of naturally infected sheep. The antibody activity in sera from sheep naturally infected with Taenia hydatigena cysticercosis or Fasciola hepatica was also tested. All the antigen preparations from native hydatid cyst fluid were able to detect antibodies in the sera from a significant proportion of sheep with natural hydatid cyst infection, as identified by inspection at slaughter, although the seroreactivity was variable. The native antigen B preparation from camel hydatid cyst fluid gave the highest sensitivity in the ELISA (total 90 per cent), with 99 per cent specificity. In all cases, the recombinant antigen B was the least sensitive antigen (25 per cent) although it was highly specific (99 per cent).