The prevalence of familial Mediterranean fever (FMF) is higher among South Asian individuals with systemic lupus erythematosus (SLE) compared with the general population, according to study results published in Reumatología Clínica.

Researchers conducted an observational study that included 3623 patients with SLE (84% women; mean age, 55±12 years) and 14,492 age-matched controls. The control group was divided into four subgroups: those with FMF; those without FMF; those with both SLE and FMF; and those with SLE but without FMF. All data were retrieved from Foundation University’s institutional rheumatology patient database. The researchers examined the proportions of FMF cases between groups and different ethnic cohorts using chi-square tests, Student t-test, and ANOVA (for univariate analysis). Data collection was used to note SLE and/or FMF prevalence by participant region.

Those in the SLE group had a significantly higher rate of FMF compared with controls (1.29% vs 0.79%, respectively; P =.015). The prevalence of SLE was higher among Pashtuns and those with a medium socioeconomic status, and FMF was more prevalent in Sindhis and Punjabis (53% each) and those with a lower socioeconomic status.


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The researchers hypothesized that cellular apoptosis in FMF created intranuclear autoantigens, which activated the adaptive immune cycle by B lymphocytes and autoantibody production, similar to the autoantibody markers in SLE. This confirmed a co-occurrence of autoinflammatory and autoimmune diseases.

Limitations to this study included the fact that no genetic tests were available for comparison, and a potential lack of real-world generalizability.

The study authors concluded, “[A] higher percentage of SLE is associated with FMF patients when compared with the general population…. [S]ymptom overlap between FMF and SLE should keep the physicians to consider the alternate diagnosis in patients with recurrent fevers and arthralgias.”

Reference

Farooq MU, Sohail H, Mohsin M, Iqbal R, Malika J, Ishaq U. Co-occurrence of familial Mediterranean fever with systemic lupus erythematosus in South Asian population. Published online June 7, 2022. Reumatol Clin. doi:10.1016/j.reuma.2022.04.002