Table 1.

Summary of biomarker studies of LBP due to unspecified diagnoses

Year	Study	Comparator groups	Number of subjects (N)	Study design	Summary of significant findings	Reference
1997	Bruunsgaard et al	Eccentric vs. concentric exercise	9	Randomized control trial	IL-6 increased after eccentric exercise.	34
1998	Ostrowski et al.	Pre- and postintense prolonged exercise	16	Randomized control trail	IL-6 increased post exercise:	35
					Pre: 1.5 ± 0.7 pg/mL
					Post: 94.4 ± 12.6 pg/mL
2005	Stürmer et al.	Acute LBP/cLBP: low vs. high pain	72 (41 chronic, 31 acute)	Longitudinal – prospective	Acute LBP: increasing CRP with increasing pain (CRP: 1.6× higher in high-pain group).	26
2006	Gebhardt et al.	Acute LBP cLBP	72 (41 chronic, 32 acute)	Longitudinal – prospective	Lower CRP with decreasing pain in acute LBP	27
2007	Rannou et al.	Modic 0, I, II changes	85	Cross-sectional – prospective	Serum hsCRP higher in modic I than 0 or II	42
2007	Uçeyler et al.	Painless vs. painful neuropathy	32 painful, 20 painless, 38 healthy control	Cross-sectional – prospective	Painful group had 2× higher blood IL-2 and TNF-α mRNA levels than painless and control groups;	37
					IL-10 mRNA levels 2× higher in painless group than painful.
2008	Wang et al.	Chronic LBP and control	120 per group	Longitudinal – prospective	Higher proportion of chronic LBP patients had TNF-α level higher than 2 pg/mL as compared with controls	45
2010	Wang et al.	Chronic LBP and control	29 per group	Cross-sectional – prospective	TNF-α levels were 25× higher in cLBP than controls.	46
2011	Park & Lee	Pre- vs. posttreatment with ESI	55	Cross-sectional – prospective	No correlation between hsCRP and VAS;	44
					hsCRP reduced posttreatment compared with pretreatment.
2012	Goode et al.	Graded scale of disc space narrowing (DSN), osteophyte formation (OST) in patients with and without LBP symptoms	547	Retrospective	Type 11 collagen (C2C) was associated with DSN;	61
					COMP was associated with DSN among patientss. with symptoms;
					HA and C2C are correlated with DSN severity.
2012	Licciardone et al.	Undefined chronic LBP by pain severity and number of osteopathic lesions	70	Substudy nested within random control trial	IL-6 and IL-1β correlated with number of osteopathic lesions;	39
					IL-6 correlated with LBP severity.
2014	Luchting et al.	Chronic LBP vs. controls	10	Cross-sectional – prospective	Increased frequency of Treg cells in CLBP patients compared with controls;	48
					decreased frequency of TH17 in cLBP compared with controls.
2014	Rathod et al.	Lumbar disc disease undergoing surgery and controls	50 lumbar, 50 control	Longitudinal – prospective	hsCRP almost 30× higher in lumbar disc disease patients compared with controls	43
2014	Sowa et al.	Before vs. after exercise	43	Cross sectional – prospective	RANTES correlated with pain and pain-related function after activity	47
2016	de Queiroz et al.	Acute LBP by pain and disability	155	retrospective	Positive correlations:	32
					TNF-α and pain severity;
					IL-6 and pain severity
2016	Deng et al.	DH vs. control	10	Cross-sectional – prospective	IL-6 higher in DH than controls;	78
					Col II and aggrecan lower in DH than controls.
2016	Grad et al.	Degenerated vs nondegenerated	80	Case control – prospective	CCL5 was 1.6× higher in degenerated group compared with nondegenerated controls;	77
					CXCL6 was 1.3× higher in degenerated group compared with controls
2016	Wang et al.	Severe vs. mild sciatica	58 severe, 50 mild, 30 healthy control	Cross sectional – prospective	IL-6: 1.5× higher in severe than mild or control;	38
					IL-8: higher in severe than control;
					TNF-a: 2× higher in severe than mild or control;
					IL-4: 2× higher in mild than severe or control;
					IL-6: TNF-αa, IL-10 correlated with ODI