Table 4

Pearson correlations of log-transformed data on kynurenine pathway metabolites and enzymes with cytokines

Cytokine*KynurenineKynurenine/TRPKYNAQUINIDO1IDO2TDO2KAT IIKMO
IL6 (n = 70)
r0.3250.4280.3040.2300.3470.3660.2790.0540.224
p0.006< 0.0010.0110.060.0040.0030.0210.670.06
 adj p0.0150.0010.0240.090.0090.0070.0390.700.10
IL13 (n = 69)
r0.2410.2780.1210.1620.4840.5070.5010.1500.360
p0.0460.0210.320.19< 0.001< 0.001< 0.0010.220.002
 adj p0.080.0390.380.230.0010.0010.0010.270.007
IL33 (n = 56)
r−0.0670.4130.1190.1660.4150.4670.5400.3810.341
p0.630.0020.380.220.002< 0.001< 0.0010.0040.010
 adj p0.680.0050.440.270.0050.002< 0.0010.0100.023
IFN-γ (n = 69)
r0.0870.2620.0350.1900.6890.7550.5330.1670.381
p0.480.0300.780.12< 0.001< 0.001< 0.0010.180.001
 adj p0.530.050.790.17< 0.001< 0.001< 0.0010.230.005
TNF-α (n = 69)
r0.1620.3020.1690.2360.4950.4370.4500.0240.360
p0.180.0120.170.05< 0.001< 0.001< 0.0010.850.002
 adj p0.230.0240.220.09< 0.0010.001< 0.0010.850.007
CCL2 (n = 69)
r0.1700.4490.3620.2970.2100.230−1.020.0470.170
p0.16< 0.0010.0020.0130.080.070.410.700.16
 adj p0.220.0010.0070.0270.130.100.460.730.22
  • adj = adjusted; CCL2 = chemokine ligand 2; IDO = indoleamine 2,3-dioxygenase; IFN = interferon; IL = interleukin; KAT II = kynurenine aminotransferase II; KMO = kynurenine 3-monooxygenase; KYNA = kynurenic acid; QUIN = quinolinic acid; TDO = tryptophan-2,3-dioxygenase; TNF = tumour necrosis factor; TRP = tryptophan.

  • * The n value includes both controls and depressed individuals.

  • Significance level for unadjusted values for multiple comparisons.

  • Adjusted for multiple comparisons using the Benjamini–Hochberg modification of the Bonferroni method.