First, based on our own measurements in college dormitories and on other reports of measurable cat allergen in public places, we know that this is not a study of complete cat allergen avoidance. of the skin test positive patients living in a house with a Triciribine cat are desensitized as if they were on active immunotherapy. Paradoxically despite the high levels of allergen exposure in the home, living with a cat is not consistently associated with an increased prevalence of sensitization to cat. 10 Indeed in some studies, children raised in a house with a Mouse monoclonal to THAP11 cat, or a dog, have been found to have a significantly lower prevalence of IgE to cat, or dog, allergens respectively.11-17 In addition to this, many of the non-sensitized children living in a house with a cat have been shown to have IgG and IgG4 Ab specific for Fel d 1.12,18 In contrast in a recent study of (n=24)(n=32)(n=41)assume that symptoms among skin test positive individuals living in a house with a cat are due to cat exposure. Now, it seems possible that some of those subjects with IgE Ab who have a major decrease in IgG Ab could develop increased symptoms on re-exposure after giving up their pets. Similar observations have been made in regards to food allergy.36 Specifically, investigators who studied cow’s milk allergy among children with eczema, reported that many who had previously tolerated milk without acute reactions experienced immediate symptoms with accidental exposure after prolonged avoidance (median 2.3 years).36 There are several limitations to our study. First, based on our own measurements in college dormitories and on other reports of measurable cat allergen in public places, we know that this is not a study of complete cat allergen avoidance. We believe the results of the study are important because they represent the reality facing our patients. Even those who choose to remove a cat from their home cannot expect to avoid exposure in the community.37-39 In all previous studies of allergen avoidance the patients have been free to visit other homes or public places where allergen exposure can also occur. Primarily the present study was designed to follow antibody responses to cat during a period of decreased exposure. We designed this study to follow immune responses in order to obtain information about which immunological group would have changes that could result in new or increased symptoms with avoidance. There were no consistent reports of change in symptoms on returning home. However, it was clear that these responses were confounded by several factors Triciribine i) the students were going to many different houses and vacation sites, most of which were too far from Charlottesville to be studied; ii) it is well established that there can be wide variation in cat allergen measurements in homes with or without a cat; and iii) many of the college students were sensitized to more than one allergen (96% of the cat sensitized group) so that it was hard to interpret whether their symptoms were related to cat exposure. For these reasons, we believe it would be hard to properly evaluate any switch in symptoms upon return to home environments. Based on our present results, we estimate that answering questions about changes in symptoms would require following at least 100 pores and skin test positive individuals for one yr in college. In conclusion, a major query in our unique strategy was whether some of the college students with IgG and IgG4 Ab, but without any evidence of sensitization, would develop IgE Ab or positive pores and skin prick Triciribine tests specific for cat during their 1st yr in college. We did not observe any instances where pores and skin checks became positive. By contrast, there were consistent decreases in IgG Ab; and among the skin test positive individuals, there were major changes Triciribine in the percentage of IgG to IgE. Therefore, raises in symptoms upon returning home could be due to the changes in antibody levels observed in pores and skin test positive subjects. While a lack of symptoms is frequently observed in individuals with positive pores and skin checks to additional allergens, the interesting factor about the individuals with IgE Ab to cat is definitely that they tolerate living with high levels of airborne exposure. The results suggest that decisions about avoidance suggestions in relation to pet cats, and probably additional home animals, should not make.