HP and systemic lupus erythematosus: Additionally, SLE patients were stratified based on their anti-dsDNA antibody levels, with groups defined by values below and above twice the upper limit of the normal range; however, no statistically significant difference in plasma zonulin level was observed between these groups (n = 16, 5.915 ± 1.744 vs. n = 25, 8.623 ± 1.945, p = 0.307, Mann–Whitney U-test).