Fig 2: (A) When comparing ME/CFS patients to healthy control participants, no statistically significant differences in serum LBP level were found. (B) Only after immunological patient stratification was serum LBP level significantly elevated in patients without immunodeficiencies (ME/CFS − ID) compared to healthy control participants. (C) A similar effect was detected when comparing the LBP/sCD14 ratio of all ME/CFS patients to healthy control participants. (D) Again, only after immunological stratification did ME/CFS patients without immunodeficiencies show a significantly higher LBP/sCD14 ratio compared to the other test groups. LOD (LBP): 0.82 ng/mL; * p < 0.05.

Fig 3: (A). Heatmap of the dietary characteristics and their association with serum zonulin. The heatmap illustrates the distribution of various dietary characteristics that correlate with serum zonulin levels. Each row represents a different component. The color gradient indicates the strength and direction of the correlation, with darker blue shades representing a positive correlation and lighter shades of red representing a negative correlation. Only p values less than 0.05 are shown. The non-significant correlations are shown in Supplementary Table S1. Abbreviations: BMI, body mass index; mg, milligrams (actual grams consumed per day);/1000 kcal refers to nutrient intake adjusted per 1000 kcal. (B). Heatmap of dietary characteristics and their association with serum lipopolysaccharide-binding protein (LBP). The heatmap illustrates the distribution of various dietary characteristics that significantly correlate with serum LBP levels. Each row represents a different component. The color gradient indicates the strength and direction of the correlation, with darker blue shades representing a positive correlation and lighter shades of red representing a negative correlation. Only p values of less than 0.05 are shown. The non-significant correlations are shown in Supplementary Table S1. Refined grains are grains that do not contain all the components of the entire grain kernel (oz. eq.) as defined by the ASA24 software (https://epi.grants.cancer.gov/asa24/, accessed on 31 July 2021) [23]. Abbreviations: PMS, partial Mayo score; FCP, fecal calprotectin; Anti-TNF, anti-tumor necrosis factor; HEI, Healthy Eating Index; g, grams; mg, milligrams.

Fig 4: Circulating LPS-binding protein and anti-LPS IgA antibody concentrations correlates with body fat mass and BMI indexes. A Plasma LPS (pg/mL) was not significantly modulated by VAT area. B Plasma LPS-binding protein (LBP) was elevated in the high VAT group compared with the low VAT group (13.6 µg/mL vs 9.3 µg/mL). C Plasma anti-LPS IgG was not shifted by VAT area. D Plasma anti-LPS IgA was elevated in high VAT group when compared with low VAT group (0.69 AU vs. 0.39 AU). n = 23–24, *p < 0.05 Welch’s t-test. E Plasma LBP concentrations significantly correlated with participant BMI (r = 0.396; p = 0.006). F Plasma LBP concentrations significantly correlated with participant % body fat (r = 0.359; p = 0.013). E Plasma anti-LPS IgA concentrations significantly correlated with participant BMI (r = 0.441; p = 0.0014). F Plasma anti-LPS IgA concentrations significantly correlated with participant % body fat (r = 0.440; p = 0.0014). n = 23–24. Pearson’s correlation coefficient (r)