Mitochondrial DNA polymorphisms are associated with susceptibility and phenotype of systemic lupus erythematosus.

The objective of this study was to investigate the possible association between mitochondrial DNA polymorphisms and systemic lupus erythematosus (SLE). A cohort from the Department of Rheumatology, Lund University Hospital, Sweden, consisting of 166 unrelated SLE patients was investigated as well as 190 unrelated healthy blood donors. Mean age at SLE diagnosis was 39 years (range 10-83) and mean follow-up time was 16 years (range 1-44). There were 87% women among the lupus patients, and the control group consisted of 98 women and 92 men from the same geographical area and with a similar age and ethnicity. The mtDNA SNP nt16189C was associated with SLE (OR = 1.98, 95% CI 1.04-3.78, P = 0.05). In addition, SNP nt13708A was associated with SLE in males (OR = 3.46, 95% CI 1.08-11.1, P = 0.04), although the number of male patients was low. Furthermore, SNP nt10398A was associated with secondary anti-phospholipid syndrome (P = 0.017, OR 8.2, 95% CI 1.1-63). In conclusion, in this study, we have for the first time investigated the possible association between SLE disease and mitochondrial DNA polymorphisms. Altogether, these novel results suggest that mtDNA polymorphisms may be associated with development of SLE and may potentially be of importance in SLE pathogenesis.