11/12/03 Is atopy less common in those with rheumatoid arthritis?SummaryThere is an increasing belief, with some evidence to support it, that the presence of human atopic disorders reflects a skewing of T lymphocyte-mediated immune responses to the Th2-type and away from the Th1-type. Furthermore, it has been postulated that stimulation of Th1 immunity causes release of cytokines such as interferon gamma which actually suppresses development of Th2-mediated atopic responses. One would then expect that it would be unlikely that Th1-mediated autoimmunity and atopy would occur commonly in the same individuals. To investigate this possibility, Hartung et al of the Univ. of Gliessen in Germany compared the case histories of 134 individuals with documented rheumatoid arthritis (RA) and a control group of 305 age/gender matched healthy blood donors. Using patient-reported information in questionnaires, they found a significantly lower occurrence of a history of pollen sensitivity (2.3%) and dust mite sensitivity (3.1%) when compared to that in controls (24.2% and 12.2%, respectively) as. Moreover, the serum total IgE levels were significantly lower in RA than in control subjects (p<0.0001). Reference Clin Exp Rheumatology 2003; 21:481-84 Editor's Comments One would have liked to see in this study: 1) a larger number of RA patients and 2) documentation of atopic reactivity by objective assessments (allergy skin testing and/or in vitro IgE antibody studies) as well as by questionnaire findings. Nevertheless, the results of this study do suggest an inverse relationship between the presence of RA and atopy. Some recent evidence suggests that the injection of BCG in infancy (a strong stimulus of Th1 responses) is followed by a reduced frequency of atopy. However, others have found no significant inverse relationship between the presence of strong delayed hypersensitivity (thought to be Th1-mediated) and atopy. Likely, more definitive conclusions may be feasible after further investigation.
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