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The balance between Th1 and Th2 cell activity is considered crucial in many autoimmune disorders.1,2 It has been suggested that rheumatoid arthritis (RA) is T1 cell predominated,3 whereas atopic diseases are T2 cell directed.4 Some recent observations5,6 of a decreased prevalence of atopy in patients with RA have received a lot of attention.7 It has been suggested that a T2 cell related disorder such as atopy might have a protective role against the onset of a T1 cell mediated disease such as RA,8 and the biological importance of the Th1/Th2 paradigm has been emphasised.
We evaluated the prevalence of atopic respiratory diseases in 126 consecutively observed outpatients with RA (diagnosed according to the American College of Rheumatology (ACR) criteria). The presence of allergic respiratory diseases was investigated in all patients by an exhaustive interview and the administration of skin prick tests by a trained allergologist. Skin prick tests were made according to the EAACI guidelines,9 with a panel including the most common airborne allergens of our area. A diagnosis of allergic rhinitis was made in 21 patients (16.6%). The diagnosis was based on a suggestive clinical picture associated with the positivity of skin prick tests. Seven of 21 patients also had symptoms of asthma and 3/21 had undergone specific immunotherapy before the onset of RA symptoms. In 20/21 patients allergic respiratory symptoms had started before the onset of RA symptoms. In 5/21 patients atopic symptoms had totally disappeared by the time of this study.
Patients with RA with associated atopic disease did not differ from other patients with RA in the following characteristics: (a) sex (76.2% female v 75.2%); (b) positivity of rheumatoid factor (71.4% v 63.8%); (c) presence of subcutaneous noduli and/or other extra-articular manifestations (14.3% v 21.9%); (d) functional class according to the ACR revised criteria (class I-II: 64% v 60%); (e) current treatment with two or more disease modifying antirheumatic drugs in combination (57.1% v 60.9%); (f) current steroid treatment (57.1% v 54.3%). Notably, most patients from both groups (90.9% v 76.8%) were taking steroids at a low dose—namely, not more than 5 mg daily of prednisone, when they were evaluated for this study.
Patients with atopic diseases were younger (mean age 53.8 v 57.5) and had a shorter average duration of RA (4.5 v 9.7 years) than those without.
We found a rather high prevalence of allergic respiratory diseases in our patients with RA (16.6%), comparable with that expected in the general population.10 Moreover, the presence of atopic disease did not seem to influence the severity of RA.
The difference between our data and other reports5,6 may be due to the methods used to determine the presence of atopic diseases. Those other studies started from the administration of standardised questionnaires to patients with RA and this method might have caused an underestimation of atopic symptoms. Conceivably, prolonged steroid treatment, as well as the systemic symptoms and disability associated with RA, may often cause occult symptoms of rhinitis and asthma that only emerge at deeper analysis.
In conclusion, our data question the hypothesis of a mutual antagonism of RA and atopy, suggesting caution in interpreting previous data and confirming that things are often not as simple as they can seem at first glance.