Suzuki et al et al found that sensitization to Can f 5 was the most frequent component in a random population (3%) and Can f 1 in an asthma sample (14%).11 Tsolakis et al found that levels of IgE to lipocalin (Fel d 4) and serum albumin (Fel d 2), but not to secretoglobin (Fel d 1) or cat extract, were independently associated with type-2 biomarkers and total IgE in young asthmatics.12 Hemmer et al recently found that individual sensitization patterns strongly mirrored current or previous pet ownership except for Fel d 1 which regularly caused sensitization also in non-owners.13 This evidence concerns the gene IGHE and asthma.