Could T(H)1 and T(H)2 diseases coexist? Evaluation of asthma incidence in children with coeliac disease, type 1 diabetes, or rheumatoid arthritis: A register study

Background: Asthma is generally regarded as a disease with strong T(H)2-typ e cytokine expression, whereas in autoimmune disorders, such as coeliac dis ease (CD), insulin-dependent diabetes mellitus (IDDM), and rheumatoid arthr itis (RA), T(H)1-type expression is seen. According to the cross-regulatory properties of T(H)1 and T(H)2 cells, one would assume that these diseases exist in different patient populations. Objective: We sought to test the hypothesis that asthma could exist in chil dren with T(H)1-type diseases, such as CD, IDDM, and RA. Methods: Comparison was made of the cumulative incidence of asthma in child ren with CD, IDDM, or RA by linking Finnish Medical Birth Register data on the whole 1987 birth cohort (n = 60,254 births) with the data of several na tional health registers to obtain information on the incidences of these di seases during the first 7 years of life. Results: The cumulative incidence of asthma in children with CD (24.6%) or RA (10.0%) was significantly higher than in children without CD (3.4%) or R A (3.4%; P < .001 and P = .016, respectively). Asthma tended to be more com mon in children with IDDM than in children without IDDM. Conclusion: These data indicate that the T(H)1 and T(H)2 diseases can coexi st, indicating a common environmental denominator behind the disease proces ses.