Biomarkers of psoriasis severity and therapy monitoring

Table 1 Potential inflammatory biomarkers and its relation with psoriasis activity, severity and therapy

Studies reports about its levels
Biomarker	In active psoriasis	Correlation with severity	After therapy	Relation (after therapy) with length of psoriasis remission
TNF-α	Increased levels[13-22]	Correlated positively[3,17-19,23]	Improved[3,19,22]	No report
	Mild psoriasis with higher levels than controls, lower than severe psoriasis[26]	Only for severe psoriasis[24]	Only for infliximab and etanercept[27]
	Not altered[3,24,25]	Correlated negatively[20]	Not improved for PUVA and NB-UVB[27]; and for Goeckerman´s therapy[25]
IFN-γ	Increased[15,17,18,21,24,33]	Correlated positively[15,18,24,33]	Improved[33]	Longer length of remission if decreased[33]
		Not correlated[21]	Not improved[34]
		Not the best predictor[17]
IL-12	Increased levels[15,18,36]	Correlated positively[15,18]	Improved[18,36]	No report
	Decreased levels[24]	Not correlated[24,36]
IL-18	Increased levels[15,18,39-42]	Correlated positively[15,18,39-42]	Improved[39]	No report
		Combined with TGF-β1, TIMP-1 and MMP-1 - superior value as predictor[42]
IL-8	Increased levels[3,14,15,17,24,25]	Correlated positively[3]	Improved[3]	No report
	Not increased[43]	Correlation only with erythema[24]	Increased significantly[25]
		Not correlated[15,17]
IL-6	Increased levels[14,15,20-22,43-45]	Correlated positively[21,22,44]; for severe psoriasis only[26]		No report
		Correlation only with desquamation and infiltration[45]	Improved[45-47]; for PUVA[22]
	Higher levels in severer forms than in mild and in controls; no differences between mild forms and controls[26]	Not correlated[43,46]	Not improved for NB-UVB and topical therapy[22]
IL-22	Increased levels[3,20,46,54-56]	Correlated positively[20,46,54,55]	Improved[3,56]	No report
			Only for etanercept[57]
		Not correlated[3,57]	Not improved for acitretin[57]
			Only in high-responders; not predictor of biologic therapeutic response[55]
IL-17	Increased levels[3,18,56,57]	Correlated positively[18,57]	Improved[3,56]	No report
	Not altered[15,59]	Not correlated[3,59]	Only for etanercept[57]
			Not improved for acitretin[57]
VEGF	Increased levels[3,43,66-71]	Correlated positively[18,55,67-70,72]	Improved[3,67,68]	No report
	Only im medium and severe psoriasis[72]		Only for PUVA[71]
	Not increased[55]	Not correlated[43]	Discordant results with NB-UVB[3,70,71]
			Increased values with retinoids combined with NB-UVB[71]
			Only in high-responders; not predictor of biologic therapeutic response[55]
IL-21	Increased levels[20,61]	Correlated positively[61]	No report	No report
		Not correlated[20]
TGF-β1	Increased levels[73]	Correlated positively[39,42,73-75] Combined with IL-18, TIMP-1 and MMP-1 - superior value as predictor[42]	Improved[77] The decrease was not significantly[76]	No report
	Not increased[74,75]
	At least for patients with a PASI < 15[76]
IL-10	Decreased[18]	Correlated negatively[18]		No report
	Below detection levels[24]	Not correlated[43]	Decreased[36]
	Increased[36,43]
CRP	Increased levels[69,78-95]	Correlated positively[69,79,84,87,90,93-95,98]	Improved[78,79,81-83,88,91,92,97,98]	Longer length of remission if decreased; predictor of length of remission[100]
	Not increased[96,97]	Correlated after treatment[82]
		Not correlated[81,99]
PTX3	Increased levels[26,81,102]	Correlated positively[26,102]	Improved[81,102]	No report
		Not correlated[81]

CRP: C-reactive protein; IL: Interleukin; IFN: Interferon; MMP: Matrix metalloproteinase; NB-UVB: Narrow-band ultraviolet light B; PTX3: Pentraxin 3; PUVA: Psoralen plus ultraviolet light A; TGF: Transforming growth factor; TIMP: Tissue inhibitors of metalloproteinases; TNF: Tumor necrosis factor; VEGF: Vascular endothelial growth factor.