To investigate the clinical, serologic, radiologic and immunogenetic characteristics of rheumatoid arthritis (RA) occurring in patients with beta-thalassemic trait as compared with RA in control patients from the same geographical area.
Twenty-eight patients with beta-thalassemic trait fulfilling the American College of Rheumatology (ACR) criteria for RA were compared with a control group of twenty-eight RA patients matched for age, sex, disease duration and place of birth. Clinical and routine laboratory assessment, including anti-keratin antibodies and anti-citrullinated peptide antibodies, was carried out in the two groups. The patients were also evaluated for HLADRB1 alleles and radiologic damage.
No differences were found with regard to clinical indexes of disease activity, laboratory parameters, and joint erosions. The immunogenetic analysis did not show any significant difference, the percentage of patients with alleles encoding for the shared epitope being similar in the two groups (61% vs. 57%). As for the extra-articular features, we found a trend for a lower prevalence of sicca syndrome in the beta-thalassemic group (14% vs. 39%; P = 0.06). Rheumatoid nodules were not found in beta-thalassemic patients while they were present in two RA patients in the control group.
The chronic polyarthritis occurring in beta-thalassemic trait carriers can be regarded as a true RA similar to that found in Mediterranean countries, possibly characterized by a low prevalence of extra-articular features.