TABLE 2.

Biomarkers significantly associated with different comparison groups.

Comparison groups	Categories of biomarkers						References
	Acute phase protein	Biochemical marker	Cytokine/Chemokine	Neurological marker	Vascular marker	Others
Long COVID vs recovered	Albumin, CRP, Ferritin, Fibrinogen	1-Methylnicotinamide, 2-Phenylphenol, 3,5-Dihydroxybenzoic acid, ALT, AST, β-glucan, Indole-3-lactic acid, LDH, L-Cystein, L-Glutamine, L-Methionine, Ornithine, Pipecolic acid, Quinolinic acid, Quinolinic acid/Tryptophan, Sarcosine, S-Sulfocysteine, Tryptase	CCL2, CXCL10, GM-CSF, IFN-γ, IL-2, IL-4, IL-6, IL-10, IL-17, IP-10, TNF-α	GFAP, NFL, pGFAP/pNFL	ET-1, Hemoglobin, NO, PDGF-BB, VEGF	Ab, Hs TnT, LBP, NT-proBNP/NT-BNP, Zonulin	(19, 20, 40, 41, 43–49, 51, 53, 54, 56–58, 60, 62, 63)
Long COVID vs healthy	Albumin, C5b-9, CRP, Ferritin	ADA, CPA3, Glutamine/Glutamate ratio, LDH, ST1A1, Taurine, Tryptase, uPA	CCL2, CCL3, CCL4, CCL5, CCL7, CCL19, CCL20, CCL23, CXCL1, CXCL9, CXCL10, CXCL11, Flt3L, G-CSF, GM-CSF, IFN-α, IFN-β, IFN-γ, IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-7, IL-10, IL-10Rβ, IL-12β, IL-13, IL-17, IL-18, IL-33, IP-10, M-CSF, SCF, TGF-α, TGF-β, TNF-α, TNF-β	GDNF, NGF-β, NT-3	Ang-2, Col1A2, Col3A1, D-dimer, ESR, ET-1, Factor VIII:C, Hemoglobin, MMP-1, MMP-9, MPO, sICAM-1, sTM, sVCAM-1, sVEGFR, VEGF, VWF:Ag, VWF:pp ARTN, α-SMA, AXIN, CASP-8, CST-5, Cystatin-C, IGFBP-4, miRNA21, MRP8/14, NGAL, OPG, OSM, SIRT2, STAMBP	ARTN, α-SMA, AXIN, CASP-8, CST-5, Cystatin-C, IGFBP-4, miRNA21, MRP8/14, NGAL, OPG, OSM, SIRT2, STAMBP, TNFRSF9	(21, 22, 42, 47, 48, 50, 52, 54, 55, 59, 61, 62)
Long COVID vs active infected	Albumin, CRP, Feritin		G-CSF, IFN-α, IL-1β, IL-6, IL-13, IL-17, IP-10, TNF-α		D-dimer, ESR, Hemoglobin		(55)

A detailed list of abbreviations in Table 2 can be found in Supplementary Table 2.