Article Abstract:
Individuals have various types of histocompatibility (HLA) antigens, which are proteins that allow the immune system to distinguish between foreign and non-foreign molecules and to respond accordingly. Individuals who have certain types of HLA molecules have a greater chance of developing certain diseases. Individuals with HLA-DR4 have a predisposition to adult-onset rheumatoid arthritis (RA). There are clinical subgroups of RA that do or do not have rheumatoid factor (RF), antibodies against a group of proteins known as globulins. The subgroups can be further divided based on the presence or absence of antiperinuclear factor (APF). Individuals with APF have antibodies to granules around the nucleus of cells; people who are APF-positive generally have more severe RA. The HLA type of 132 individuals with RA was examined. The HLA type HLA-DR4 was present in 31 out of 55 (56 percent) individuals who were positive for both RF and APF, 29 out of 39 (74 percent) individuals who were positive for RF but negative for APF, 10 out of 14 (71 percent) individuals who were RF-negative but positive for APF, and 9 out of 24 (37 percent) individuals who were negative for both RF and APF. The prevalence of HLA-DR4 was similar in groups positive for both factors and positive for at least one of the two factors, and lower in individuals who were negative for both factors. The overall prevalence of HLA-DR4 in patients with RA was greater than in the general population; prevalence among healthy controls was 55 out of 277, or 20 percent. The study concluded that HLA-DR4 is more prevalent in patients who are seronegative for RF and contain APF, compared with RF-seronegative patients who do not have the APF. This immunogenetic finding may be important in understanding differences among the various subgroups of RA. (Consumer Summary produced by Reliance Medical Information, Inc.)
so is the testing for this HLA antigen very expensive?
It would give a definite blood marker for sero-negative RA'ers, yes?
[QUOTE=babs10]so is the testing for this HLA antigen very expensive?
It would give a definite blood marker for sero-negative RA'ers, yes?
[/QUOTE]