Table 1.

Overview of biomarkers and representative references

Effect	Class	Variable
Risk of WTC-LI	Inflammation	GM-CSF; MDC [41]
	Matrix metalloproteinases	MMP-1 [42, 44]
	Immunoglobulins	IgE [43]
	Metabolic/clinical characteristics	Dyslipidemia, obesity, insulin resistance, elevated heart rate, elevated leptin [48–51]
	Lipid/RAGE axis	LPA; sRAGE [52, 53]
	Apolipoproteins	ApoAI, ApoAII [40, 52]
	Leukocytes	aNeutrophils; aEosinophils [94]
	Serpins	aLow alpha-1 antitrypsin; decreased PEDF [38, 56]
	Interleukins	aIL- 4, -5, and -13 [95]
	Cardiovascular markers	CRP, MIP-4 [40, 44]
Protective of WTC-LI	Matrix metalloproteinases	MMP-3 and -12 [44]
	Protein	GRO and MCP-1 [42, 56]
	Neuroendocrine peptide	Amylin [48]
Post-WTC FEV1 recovery	Macrophage activity marker	Chitotriosidase [43]
	Matrix metalloproteinases	MMP-2 [42]
	Matrix metalloproteinase inhibitor	TIMP-1 [42]
WTC-AHR	Metabolic syndrome characteristics	Obesity, insulin resistance, dyslipidemia, HTN [49, 50]

AHR airway hyperreactivity, APO apolipoprotein, CRP C-reactive protein, GM-CSF granulocyte–macrophage colony-stimulating factor, GRO growth-regulated oncogene protein, HDL high-density lipoprotein, HTN hypertension, Ig immunoglobulin, IL interleukin, LPA lysophosphatidic acid, MCP monocyte chemoattractant protein, MDC macrophage-derived chemokine, MIP macrophage inhibitory protein, MMP matrix metalloproteinase, PEDF pigment epithelium-derived factor, sRAGE soluble receptor for advanced glycation end-products, TIMP tissue inhibitors of metalloproteinases, WTC-LI world trade center lung injury

^aAlso associated with accelerated FEV₁ decline