DR4prevalence related totheage atdisease onsetin female patients withrheumatoid arthritis

suMMARY TheprevalenceofHLA-DR4inrelation to age at disease onset was calculated in 226 consecutivefemalepatientswithdefinite or classical rheumatoidarthritis (RA). Aslight increase in the prevalence ofDR4with age at RA onset was found. This appeared to be due to the low percentage ofrheumatoidfactor (RF)positivity in the youngest agegroups; theDR4prevalence in the RF positive patients was constant for all decades-that is, approximately 60%. A previously reporteddeclining trend ofDR4prevalence in women with RAin relation to age of RA onset may bedue to the disease heterogeneity ofthe patients included in that study. The relation between HLA-DR4 and rheumatoidarthritis (RA) has been well established.1-3 In previous studies a significantly higher HLA-DR4 prevalence was found in womenwith RAthan inmale patients,4 as well as a stronger association of HLA-DR4withearly onset RA.4 5 In one studythe strong association between HLA-DR4 and early onset RAwas seen only in women.6 The question whether