Pork – Cat Syndrome
Below is a summary of a presentation on Pork – Cat Syndrome by Jonathon Posthumus, MD, an allergy fellow at the University of Virginia, presented at the 51st Annual Swineford Meeting held at the University of Virginia April 2012.
Pork – cat syndrome was first reported in France, by Drouet et al, in pt with FDEIA after eating pork. RAST inhibition confirmed shared allergen identified as albumin (67kD) with further characterization revealing that the cross reactivity between cat dander and pork meat are due to shared epitopes on albumin. In European literature, Pork – Cat syndrome symptoms are typically immediate in onset ( OAS, FDEIA and fatal anaphylaxis) with specific IgE to cat epithelium, cat serum albumin and pork meat. Symptoms may be inconsistent and related to co factors such as exercise, alcohol ingestion and dose.
Patients are exposed to animal serum albumins in potentially three way: inhalation, ingestion and dermal exposure. For inhalation, house dust contains high levels of cat albumin, even more than Fel d 1. For ingestion, pork, beef and lamb contain large amounts of albumin. As dermal exposure, children with AD have higher incidence of beef allergy.
IgE cross reactivity against albumins in pt allergic to animals. 200 subjects allergic to animal dander. 30% had specific IgE for various species albumin. Most had high level of cross reactivity between cat, dog and horse. A few albumin sensitized patients demonstrated IgE highly specific for one species.
UVa study to determine specificity of IgE to serum albumin studies. IgE adsorption studies done with porcine, canine, feline and human serum albumin. Sera of 3 patient with cat – pork syndrome used. Studies revealed that IgE to pork meat and porcine serum albumin was completely bound by cat serum albumin. In addition, IgE to cat serum albumin was not completely adsorbed by porcine nor dog serum albumin. All suggesting that sensitization to cat serum albumin is primary event.
Further UVa studies looked at epidemiology of sensitization to cat cat serum albumin in birth cohort of 200 US children and 963 subject from Sweden. Of the 200 US subjects: 31% sensitized to mite, 8% to egg and 3% to cat serum albumin. Of the 963 in Swedish cohort: 242 had IgE to cat epithelium and of those 215 screened for cat serum albumin with 25 being positive for a prevalence of 3%.
Conclusions:
Pt with immediate reactivity to mammalian meats may have IgE to cat and dog albumins.
The structure of albumin is highly conserved through mammalian species which likely accounts for cross reactivity between pork and other meats.
UVa adsorption data suggests that primary sensitization in these cases is feline and/or canine serum albumin rather than pork serum albumin.
Some other clinical pearls:
Cat serum albumin: Fel d 2
Dog serum albumin: Can f 3
In the presentation of three patients clinical history, one patient they used a milk challenge as a surrogate for albumin as milk is very high in albumin. Pt had OAs and urticaria from the milk challenge.
References:
Drouet et al Allerg Immunolog 1994;Oct 26(6) 305-6
Drouet et al Allerg Immunolog 1994; 166-68
Spitzeuer et al JACI 1995;96:951-9
Drouet et al Allerg Immunolog 2001; Apr 33(4):163-5
