News - Rheumatoid Arthritis And Cat Exposure Linked To DRB1 Gene

[Guest guest]

Rheumatoid Arthritis And Cat Exposure Linked To DRB1 Gene

12/28/2000

By Rose

Prior close exposure to cats in genetically susceptible subjects can lead to the

development of rheumatoid arthritis, according to a recent report from

Australia.

Researchers in the rheumatology departments.of Hospitals in Adelaide and

Melbourne designed a study to determine if the presence of HLA-DRB1 alleles

bearing the rheumatoid arthritis (RA) susceptibility motif influenced risk for

the disease, following prior pet exposure.

This study followed a previous case control study indicating the risk between

pet exposure and RA development. This acknowledged the potential for pets to

become reservoirs for microbial agents, capable of stimulating chronic

inflammation, under immunogenetic influence, in susceptible subjects.

Participants included all available patients with RA and their case controls who

had formed part of the previous epidemiological study. All provided blood

samples.

Sequence analysis of oligonucleotides determined the DR and DQ genotypes, which

were amplified by polymerase chain reactions from the DRB1 and DQB1 genes.

Subjects were then segregated , according to previously determined pet exposure

and genotype, for statistical analysis.

The odds ratio (OR) for pre-pubertal exposure to cats and RA in available

subjects irrespective of DRB1 genotype was 4.2. The OR between prior exposure to

cats and RA in subjects carrying the RA susceptibility genotype DRB1 *0401 and

*0404 was 5.8 and >24, respectively.

There was no remarkable association seen between RA and pet exposure in patients

who were selected according to other genotypes.

There was a slightly stronger association between RA and the recognized HLA-DR

susceptibility motif in subjects with a history of an intimate cat exposure,

compared with subjects with no previous close contact.

Researchers concluded that the findings suggested an interaction between an

environmental agent associated with pet cats and certain RA

susceptibility-conferring DR genotypes. The risk for RA associated with intimate

cat exposure also was significant in subjects with DRB1 *1501. This is a

genotype not otherwise associated with RA but shares with known RA

susceptibility-bearing alleles, the presence of an electropositive pocket

(Pocket 4) in the DR peptide binding groove.

http://www.docguide.com/news/content.nsf/news/5555F262DC9CD4CD852569B300712BD7?O\

penDocument & c= & count=10 & id=48DDE4A73E09A969852568880078C249