Table 1.

Candidate molecular biomarkers for idiopathic pulmonary fibrosis and the strength of evidence supporting their clinical role

Biomarker	Predisposition	Diagnosis	Prognosis	Therapeutic
Genomic
SPC	±
SPA2	±
MUC5B	±		+
TERT/TERC	±
Telomere length	±		±
ELMOD2	±
TOLLIP	±		±
TLR3	−		±
Blood proteins
SPA		±	±	−
SPD		±	±	−
KL6/MUC1		±	±	−
α-Defensins			±
cCK18		±
CCL18			±
YKL40			±
Anti-HSP70 IgG			±
CXCL13			±
MMP7		±	+
MMP1		±	±
OPN			±
Periostin			±
Blood cells
CD28% CD4+ T cells			±
Tregs			±
Semaphorin 7a+ Tregs			±
Fibrocytes			±

Key: No molecular or cellular biomarkers have a proven clinical role in IPF, but the strength of evidence supporting a potential role is denoted as follows: +, Consistent or strong evidence supporting potential role; ±, conflicting or inadequate evidence to support potential role; −, consistent or strong evidence against a potential role; blank, no evidence. SPC, surfactant protein C gene mutations; SPA2, surfactant protein A2 gene mutations; MUC5B, mucin 5B promoter polymorphism; TERT/TERC, telomerase gene mutations; ELMOD2, ELMO containing domain 2 gene mutations; TOLLIP, Toll-interacting protein gene mutations; TLR3, toll-like receptor 3 gene mutation; SPA, surfactant protein A; SPD, surfactant protein D; KL6/MUC1, Krebs von den Lungen 6/mucin 1; cCK18, cleaved cytokeratin 18; HSP, heat shock protein; CXCL, C-X-C motif chemokine; MMP, matrix metalloproteinase; OPN, osteopontin; Treg, regulatory T cell.