A cross-sectional study was done on asthmatics whose diagnosis had been clinically confirmed by physical examination and pulmonary function test (PFT)among pregnant women who were referred to Mobini Hospital in Sabzevar between August 2014 and April 2015. The Ethics Committee of Sabzevar University approved the study protocol. The Radio-allergo-sorbent test (RAST) was done, using allergen extracts, to determine the patients' sensitivity to food and inhalation allergens. (20). RASTs were carried out using standardized allergen extracts for the following 36 aeroallergens and 36 food allergen: aspergillus fumigatus, cat, dog, cow, sheep, cage bird mix, sweet vernal grass, horse, Alternaria alternata, Cladosporium herbarum, pollens [tree (Ashe, Tree mixture), (Russian thistle,], mites (Dermatophagoides pteronyssinus, Dermatophagoides farine), feathers mixture, cockroach peanut, seafood mix 3, banana, orchard grass, cultivated rye, alder, penicillium notatum, English plantain, goosefoot, rough pigweed, rice, grain mix 2, apple, cultivated oat, meadow foxtail, firebush, sorrel, tree mix 6, honeybee venom 1, house dust, cross-reactive carbohydrate determinants (CCD) marker, shrimp prawn, white pine, tree mix 4, rye flour, potato, rose, cultivated oat. From those mothers with clinically-confirmed asthma, in the final weeks of pregnancy, 7 cc of blood was drawn for total IgE and RAST. Additional blood samples from their neonates were obtained first day after delivery for the identical lab tests. The clot sample for allergens samples were transported to the laboratory quickly. Total serum was kept at -20° C until testing. Allergen samples for each series of experiments were stored at 4 ° C for up to 2 weeks, collected and tested. This methodology continued until all the required samples were gathered. Tests were performed using the ELISA kit (Euroimmun, Germany). In those patients with allergies to a wide variety of allergens, additional inhalation and food allergens were tested. Blood samples were processed in accordance with kit instructions, i.e. based upon the multiplex immunoblots method. Then the results of total serum IgE, using standard and allergens results, were evaluated with the software. Mothers were considered to be atopic if they had IgE ?160 kIU/L, infants if their serum IgE ?10 kIU/L. Any additional patient history was also recorded. The results were analysed using SPSS version 20.

RESULTS

Cohort description
Out of 1603 pregnant women 34 (2.1%) had asthma. The majority of asthmatic patients were either 25-29 years (29 %) or ?35 years (35.3%) of age. The frequency of atopy in the study population of 34 asthmatic mothers and their infants was calculated as 7 (21%) and 4 (12%), respectively. Some allergens were much more common than others. (Tables 1, 2). Food allergy was defined as sensitization to at least 1 food allergen and was present in 28%. In a multivariate analysis, we found a significant relationship between prematurity and atopy or asthma (P = 0.006).

Allergies of pregnant women are related to asthma
To describe potential factors that might be connected to asthma during pregnancy (AP), we included the following parameters: eczema, allergies, asthma severity, asthma control, atopy, IgE, seafood mix 3 and rough pigweed. As controls, the same parameters were tested in the non -asthmatic mothers. The data were analysed using the chi-square statistic and Fischer's exact test. The highest rates of allergies were in the asthmatic group: 32 (94.1%) (p = 0.001). The majority of subjects in the asthmatic group did not have eczema, 30 (88.2 %). Asthmatic patients were divided into those with intermittent/mild persistent asthma (IMPA), and moderate or severe persistent asthma (MSPA). We found no significant relationship between atopy and asthma severity, with 22% and 14% atopy in IMPA and MSPA respectively. As well, there was no significant relationship between asthma control (i.e well-controlled, vs. partly/poorly-controlled) and atopy with 23% and 19% atopy, respectively. There was no association between atopy, and allergy or eczema (Fischer's exact test p=0.37 and p=1.0, respectively). There was also no significant statistical association between atopy and seafood mix 3 or rough pigweed, (both p=1.0) or any other allergen tested.

Hence, it appeared that only having allergy at pregnancy was closely linked to asthma, and it would be interesting to determine whether asthma might also be linked to additional health issues.

Atopy and location-dependent wheezing or exercise-induced wheezing of pregnant women are related.
To investigate whether further factors might also have contributed to AP, we tested the following factors: asthma severity, common allergens, smoker, passive smoker, atopy and infant gender.
There was a positive statistical association between atopy and location-dependent wheezing or exercise-induced wheezing, p=0.048 and p=0.004, respectively. There were no association between asthma severity and the most common allergen in asthmatic mothers, p=0.71 (Table 3). Table 4 shows the distribution of the variables retrieved from the databases for atopic women included in the study. There was no significant relationship between atopy and smoking or passive smoking p=0.51 and p=0.58, respectively. Taken together, it appeared that both allergy and atopy and location-dependent wheezing and exercise-induced wheezing in pregnant women were associated with a higher prevalence of asthma.

Table 1: Positive RAST results in cord and infant blood


Table 2: Positive RAST results in pregnant women with asthma

Table 3: Frequency of positivity to seafood mix 3 in relation to asthma severity

IMPA: intermittent asthma/mild persistent asthma; MSPA…moderate and severe persistent asthma

Table 4: Characteristics of pregnant women with asthma by atopy status

DISCUSSION

This study is the first in Sabzevar to assess the prevalence of asthma and allergic sensitization and its association with IgE factors in pregnant women with asthma. Sabzevar is a city in north-eastern Iran. The region is semi desert with hot and dry summers and is an agricultural center for grape and raisin farming. In the present study, we looked into the possible connection between asthma and allergens. We found a significant relationship between allergies and asthma as well as atopy and location-related and exercise-induced wheezing in pregnant women. Atopy and asthma severity, atopy and allergic sensitisations to various food and inhalation allergens were not statistically significantly related.

We observed that food allergens were more common than aeroallergens in both mothers and infants. The frequency of atopy in asthmatic mothers and their infants were 21% and 12%, respectively. Our results are similar to those of Nabavi (2013). (14) It is possible that there are relations between the in utero environment in asthmatic pregnancies and the development of asthma during childhood, independent of genetic factors. This is suggested by atopy in children, which was more frequently related to maternal asthma or IgE levels, rather than paternal asthma or IgE.(15) The study prospectively followed 181 AP, 62% of whom were classified as atopic.(16) Comert reported a prevalence of 32.2% atopic cases in his study (17). This difference as compared with the findings in the present study is probably due to climatic factors (12).

This study is the first report of sensitization to food allergens in our region. A high rate of sensitisation to pollens was established in earlier studies in our country. A study in Mashhad (18), Iran reported that weeds had the highest rate of sensitization, among which Russian thistle (salsolakali) was the most common in childhood. This result is similar to our results in infants but, probably due to the dry climate or different method of testing, it was not the most common. Whereas we used the RAST, they applied the skin prick test. Also, in Shiraz, the prevalence pattern of sensitisations to different types of pollens (e.g weed, grass, trees), as well as in Tehranand Karaj (12) (herbacee I/II/III, sycamore, chenopodium, tree mix, grass, ash and cedar) was similar to our study. In the Comert (2014) study, the most prevalent allergen was Phleumpratense (19.3%), whereas in our study, it was seafood mix 3 (29.4%). (17) In our study, food allergens were the most common in mothers and grass and peanut allergens in infants. Herbal topography, climate and temperature could be responsible for the difference. (18) Our results were similar to most European countries in that three to four allergens were recognized in 95% of all sensitized subjects. (17) It is well-known that allergic patients are commonly co-sensitized against different allergen sources. Advancement in the field of allergen description by molecular biological techniques has now shown that sensitization against different allergen sources can be clarified as cross-reactivity of IgE antibodies with fundamentally and immunologically linked components existent on these allergen sources. (12) A survey in Kerman indicated that allergies to food and airborne allergens differ depending on the nutritional and environmental settings. (19) The sensitization rates to grass pollen varies between 19.5% and 69.9% among European countries, and it is the most common allergen in Austria, Denmark, England, Greece, Poland, Switzerland and the Netherlands (17). In contrast in Comert's study, the prevalence of Dermatophagoides pteronyssinus and Dermatophagoides farinae was also high 16.2% and 10.5%, respectively. The sensitization rates to Dermatophagoides pteronyssinus varied between 16.8% and 68.8% within European countries. Indeed, it is the most common allergen in Belgium, France, Italy and Portugal. In our results, the frequency was 2.9%. Two studies in Turkey reported the prevalence of sensitization to allergens from cats and dogs. There is a growing tendency towards pet ownership in our country (20, 21), so this may become a problem in the future. In Comert's study, the sensitization rates to Alternaria, Aspergillus and Cladosporium were 1.1%, 0.9% and 0.7%, respectively. In Europe (22), however, the rate of Cladosporium allergies was reported to be between 0% and 12.8%. The cockroach allergen would have been an important allergen to assess if we had been able to test all of the subjects against this allergen. Mert's study reported 74.22% cockroach sensitisations (17)
Whereas a study in Ahvaz found the most prevalent sensitizing mould was C. acremonium followed by Penicillium spp, we did not find that the infants were sensitized to these; although we tested them for Penicillium spp and Aspergillus allergen. (24) Penicillium, aspergillus, and basidiospores are some of the fungal species that are associated with asthma and atopy in children (25). We found only one such subject. Bunyavanich (2014) reported that exposure to wheat during early pregnancy was associated with reduced odds of mid-childhood allergy and asthma. Alterations in immune function have been proposed as a mechanism contributing to later development respiratory disease (26). Since we have only investigated neonates, the further development of this group is a matter of further study.

The group of 34 asthmatic patients tested with the 36 food and 36 aeroallergen panel were comparatively young which could overestimate the prevalence of allergen sensitivity.(17) Our findings suggest a negative relationship between location and exercise-related wheezing and atopy and a slightly positive association between atopy and maternal and passing smoking. We found no statistically significant associations between atopy and method of delivery, parity, number of gravidities, and abortions. However, Pistiner's (2008) findings suggest that cesarean delivery is associated with allergic rhinitis and atopy among children with a parental history of asthma or allergies. This likely differs from our study due to the alternative characteristics of the populations we each studied, as well as the duration of follow-up and definition of the outcomes. (23) The Mean (SD) age of our asthmatic patient group 30.97 ±6.36 versus 27.33 ±5.91 seems to be lower than in the Spanish study, i.e, 36.2 ±12.72 versus 30±15 years, respectively, which could account for the lower prevalence of atopic sensitization found in our study. Another possibility may be that the Spanish study consisted mainly of patients with allergic rhinitis; with 37% of them having asthma. (17)

Our main limitation was the lack of lab tests in the control group. A smaller sample size in contrast to earlier studies was another weakness of our study.

CONCLUSION

According to the results and environmental condition in the area of our study, the most common regional allergens were food allergens such as seafood mix 3 and peanut that should be given more attention. It may be important in future studies to try to detect local allergens that have a potential of materno-fetal transfer.

Acknowledgments
This work was approved by the ethics committee of the Medical University of Sabzevar, Iran (Medsab Rec.93.36). We thank the vice-chancellor of the Sabzevar university -Iran for financial support of this research .We thank the personnel of Mobini and Vaseei Hospitals for their cooperation. We also thank all the mothers who participated in the study.

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