Objective: The interleukin (IL)-10 single nucleotide promoter polymorphism (SNP) -2849A is associated with decreased IL-10 production as measured by lipopolysaccharide (LPS) stimulated whole blood cultures. A low innate production of IL-10 using the same assay is associated with an increased risk of familial osteoarthritis (OA). We investigated the association of 7 novel SNP located downstream of the IL-10 transcription start site: -2849,-2763, -1330, -1082, -819, and -592, constituting the 4 ancient haplotypes, with distal interphalangeal (DIP) OA.
Methods: The study population comprised consecutive patients with and without radiological DIP OA (Kellgren-Lawrence score of > or = 2 in one joint) aged 40-70 years from a cohort of subjects with different types of arthritis in an early stage referred to an Early Arthritis Clinic (EAC). DNA typing for IL-10 SNP as well as radiographs of the hands were performed at clinic enrolment. Patients with rheumatoid arthritis, systemic lupus erythematosus, spondyloarthropathies, and psoriatic arthritis were excluded.
Results: The distribution of DIP OA and IL-10 SNP were comparable to representative samples of the Dutch population. In the cohort of 172 subjects, 57 had DIP OA (33%) and 115 (67%) had no DIP OA. No significant association was found between DIP OA and IL-10 SNP and the 4 common haplotypes IL10.1, IL10.2, IL10.3, and IL10.4.
Conclusion: Our data suggest that IL-10 SNP, including -2849, which is associated with differential production, do not play a major role in the susceptibility of DIP OA.