| 
      (a)Student’s t-test; p< 0.001***; p<0.01**; p<0.05*
        | pSS    patients (n= 15) | Controls    (n= 15) |  
        | Metabolite | Concentration    (µM) | Concentration    (µM) | Significance P value (a)
 |  
        | Mean     ±  S.D | Range | P    value (a) | Range |  
        | Acetate | 1482.7 ± 952.6 | 202.7-3676.6 | 1503.0 ± 715.2 | 670.6-3035.2 | 0.948 |  
        | Alanine | 23.7 ± 13.2 | 7.0-55.6 | 11.4 ± 7.3 | 2.5-27.6 | 0.004** |  
        | Butanol | 14.1 ± 12.1 | 1.5-45.1 | 8.6 ± 5.8 | 0.8-20.7 | 0.126 |  
        | Butyrate | 34.7 ± 29.0 | 7.2-107.8 | 16.4 ± 10.9 | 2.5-34.9 | 0.034* |  
        | Choline | 11.4 ± 5.3 | 4.5-24.7 | 4.1 ± 2.0 | 1.0-7.1 | <0.001*** |  
        | Citrate | 18.3 ± 7.9 | 7.2-34.4 | 18.3 ± 13.8 | 3.4-46.5 | 0.996 |  
        | Ethanol | 25.4 ± 12.8 | 7.2-57.7 | 26.3 ± 59.6 | 7.9-241.3 | 0.956 |  
        | Formate | 152.0 ± 195 | 6.3-660.8 | 80.1 ± 63.3 | 3.3-220.5 | 0.192 |  
        | Fucose | 46.5 ± 35.9 | 3.7-113.6 | 66.3 ± 40.3 | 20.2-150.5 | 0.167 |  
        | Glycine | 150.9 ± 120.5 | 16.0-387.7 | 51.5 ± 35.4 | 8.7-152.3 | 0.007** |  
        | Histidine | 30.3 ± 13.9 | 8.7-53.8 | - | - | - |  
        | Isopropanol | 1.84 ± 0.8 | 0.2-3.7 | - | - | - |  
        | Lactate | 265.6 ± 140.4 | 25.4-509.7 | 198.3 ± 174.5 | 14.1-649.0 | 0.255 |  
        | Methanol | 28.5 ± 17.5 | 9.7-65.6 | 27.7 ± 9.2 | 8.3-43.9 | 0.878 |  
        | Methylamine | 2.1 ± 1.7 | 0.5-5.7 | 2.0 ± 0.9 | 1.1-3.8 | 0.818 |  
        | Phenylalanine | 14.3 ± 8.4 | 2.6-28.6 | 8.5 ± 3.6 | 2.6-16.8 | 0.026* |  
        | Proline | 133.5 ± 114.5 | 9.1-362.9 | 59.1 ± 44.1 | 17.8-160.5 | 0.032* |  
        | Propionate | 284.3 ± 205.7 | 49.8-722.1 | 235.7 ± 156.2 | 69.0-621.9 | 0.472 |  
        | Pyruvic    acid | 17.6 ± 11.2 | 0.9-37.5 | 10.4 ± 7.8 | 0.0-24.3 | 0.050 |  
        | Succinate | 33.8 ± 32.1 | 6.7-131.8 | 28.2 ± 15.7 | 5.3-49.5 | 0.549 |  
        | Taurine | 110.5 ± 49.6 | 18.6-213.0 | 48.3 ± 29.0 | 12.5-111.5 | <0.001*** |  
        | Trimethylamine | 1.4 ± 1.4 | 0.1-4.9 | - | - | - |  
        | Tyrosine | 26.7 ± 18.5 | 5.1-75.4 | 19.6 ± 11.4 | 6.4-50.5 | 0.215 |  
        | 1,2-propanediol | 40.1 ± 71.4 | 9.2-290.0 | 27.3 ± 14.2 | 9.8-59.0 | 0.500 |  |