Molecular diagnosis in cat allergy

Table 3 Allergens used in singleplex and multiplex immunoglobulin E immunoassays in patients with cat allergy[7,8,10,28,29]

Protein family	Allergen	IgE sensitization biomarker
Secretoglobins	rFel d 1	Major cat allergen, species-specific biomarker of primary sensitization to cat, as efficient as or even superior compared to natural cat extract in diagnosis
Lipocalins	rFel d 4	Major cat allergen, biomarker of cross-sensitization to other animal lipocalins, cross-reactive with lipocalins dog rCan f 6, horse rEqu q 1, and mouse nMus m 1
	rFel d 7	Minor cat allergen, biomarker of cross-sensitization to dog lipocalin, cross-reactive with lipocalin dog rCan f 1
Serum albumins	n/rFel d 2	Minor cat allergen, biomarker of sensitization to non-human serum albumin, cross-reactive with pork rSus d1/nSus s1 (cat-pork syndrome) and other serum albumins bovine nBod d 6, dog nCan f 3, and horse nEqu c 3
Immunoglobulins	nFel d 5	Minor cat allergens IgA Fel d 5 and IgM Fel d 6 carry α-Gal epitopes involved in the α-Gal syndrome and in impairing cat allergy in vitro diagnostics in parasite-infected patients; α-Gal biomarker: nBos d TG

Major cat allergen: Allergen recognized by immunoglobulin E antibodies of > 50% of cat allergic patients; Minor allergen: Allergen recognized by < 50% of the allergic population; IgA: Immunoglobulin A; IgM: Immunoglobulin M; α-Gal: Galactose-α-1,3-galactose; TG: Thyroglobulin, bovine.