Cytokines as biochemical markers for knee osteoarthritis

Table 1 Summary of studies in which cytokines have shown biochemical marker characteristics

Ref.	Year	Cytokines	Joint	Tissue	Condition of samples	Samples	Controls	Assay	Follow-up	Results
Sun et al[65]	2013	IL-15	Knee	Serum	Primary Knee OA	226	106	ELISA	N/A	IL-15 Serum OA ↑ Control
										IL-15 positively correlated with WOMAC (Pain)
										IL-15 not correlated with KL
Shimura et al[45]	2013	IL-6	Knee	Serum	Postmenopausal females with medial knee OA	160	N/A	CLIA	N/A	Serum IL-6 = association with pain severity (VAS) in early stage
										Serum IL-6 = association with pain severity (JKOM) in early stage
Wang et al[66]	2013	IL-18	Knee	Plasma, SF and Articular Cartilage	Primary Knee OA	33	15	ELISA + Immunofluorescence Staining	N/A	IL-18 Plasma +SF OA ↑ Controls
										IL-18 positive cells AC OA ↑ Controls
										↑ KL = ↑ IL-18 Plasma, SF + AC + ↑ IL-18 positive cells
										IL-18 Plasma, SF + AC = Positive correlation
Vincent et al[59]	2013	IL-1β, IL-6, IL-8, IL-12, TNF-α, IL-4, IL-10 + IL-13	Knee	SF	Chronic OA	Adult (50-64 yr): 14 Elderly (≥ 65 yr): 14	N/A	Multiplex	6 mo	↓Pain severity (NRSpain) = ↓IL-1β
										↓ IL-1β, IL-6, IL-8 + IL-12 (Baseline – 6 mo) Adults vs Elderly (not significant)
										↓ TNF-α (Baseline – 6 mo) in Adults vs Elderly
Rubenhagen et al[42]	2012	IL-1Ra, IL-6, IL-8, IL-10, IL-17, VEGF, MCP-1, IL-7, IL-13, IL-18 + HGF	Knee	SF	Total knee replacements or cruciate ligament, cartilage, or meniscal reconstruction surgery	82	N/A	Multiplex + ELISA	N/A	↑ SF IL-7 = ↑KL
										SF VEGF 2 ×↑ KL=3/4 vs KL=0
										IL-7 = positive correlation with age
										IL-7 2 ×↑ > 60 years old vs < 60 years old
										IL-1Ra, IL-6, IL-8, IL-10, IL-17, MCP-1, IL-13, IL-18 + HGF ≠ association with KL
Chadjich- ristos et al[32]	2012	IL-1β + TNF-α	Knee	SF	OA Established (Medial menlsectomy)	25	5	ELISA	N/A	↑ IL-1β + TNF-α = ↑ Degree of Inflammation
										IL-1β + TNF-α↑ in weeks 2 + 4
										IL-1β↓ in week 12
										TNF-α↓ in weeks 8 + 12
Saetan et al[83]	2011	IP-10	Knee	Plasma + SF	Knee OA	40	15	ELISA	N/A	OA SF IP10 2.5 ×↓ than plasma
										OA SF IP10 3 ×↓ than control plasma
										↑KL = ↓Plasma + SF IP-10
										Plasma + SF IP10 inversely correlated with KL (SF less so)
Vangsness et al[84]	2011	IL-1β, IL-6, IL-8, IL-12p70, IFN-γ, IL-2 + IL-5	Knee	SF	Patients underwent an arthroscopy of the knee for a meniscal tear	12	N/A	Immunoassay high-throughput flow cytometry	N/A	↑ IL-2 + IL-5 = ↑ Disease severity (ICRS)
										↑ IL-1β, IL-6, IL-8, IL-12p70 + IFN-γ = ↑ Disease Severity (ICRS) (Borderline significance; P < 0.10)
										IL-1β, IL-6, IL-8, IL-12p70, IFN-γ, IL-2 + IL-5 ≠ association with KL
Orita et al[85]	2011	IL-6, TNF-α + NGF	Knee	SF	Adult patients with knee pain - No previous OA treatment	47	N/A	ELISA	N/A	TNF-α≠ correlation with KL
										TNF-α↓ KL (2-4) vs KL (1)
										TNF-α = Positive correlation with WOMAC + WOMAC (Pain, stiffness + physical function)
										IL-6 = Negative correlation with KL
										IL-6 ↓ KL (3 + 4) vs KL (1 + 2)
										IL-6 = Negative correlation with WOMAC (Stiffness)
										IL-6 ≠ correlation with WOMAC or WOMAC (Pain or physical function)
Kokebie et al[86]	2011	IL-1, IL-6, IL-8, IL-11, LIF, COMP + osteocalcin	Knee	SF	Fulfilled ACR criteria	45	RA: 22 Donor: 20	ELISA	N/A	IL-8 RA ↑ OA + Donors
										IL-11 RA = OA
										IL-11 OA ↑ Donors
										LIF Donors ↑ OA + RA
										LIF OA = RA
										SF WBC positive correlation with IL-6 + IL-1
										IL-11, IL-8 + LIF no correlation with SF WBC
										No biomarkers correlated with KL or disease activity (WOMAC)
Santos et al[87]	2011	IL-6	Knee	Plasma	Knee OA (ACR)	80	N/A	ELISA	N/A	IL-6 = inverse correlation with muscle resistance + muscle balance (hamstring)
										IL-6 ≠ correlation with functionality
Stannus et al[48]	2010	IL-1 β, IL-6, TNF-α + hs-CRP	Knee	Serum	Selected randomly from the roll of electors	172	N/A	CLIA	3 yr	IL-6 + TNF-α Serum = association with JSN (medial tibiofemoral)
										IL-6 + TNF-α Serum ≠ association with cartilage volume (tibial)
										IL-6 Serum predicted ↓ cartilage volume (medial + tibial)
										IL-6 + TNF-α associated with ↓ cartilage volume (medial + lateral)
										TNF-α associated with JSN
										IL-6 serum associated with knee JSN + Knee cartilage loss (older patients)
Stannus et al[44]	2010	IL-6	Hip	Serum	Selected randomly from the roll of electors	193	N/A	ELISA	N/A	IL-6 Male = Female
										↑ IL-6 = ↑ JSN (Female)
										IL-6 ≠ association with JSN (Male)
										Trunk-fat + Total Fat ratios associated with IL-6
										IL-6 ≠ association with presence or severity of osteophytes
Scanzello et al[88]	2009	IL-15, IL-1β, IL-6, TNF-α, IL-2 + IL-21	Knee	SF	Early: degenerative meniscal tears Adv: Knee replacement surgery	Early: 19 Adv: 15	N/A	ELISA + Quantitative PCR	N/A	SF IL-15 ↑ early vs advanced
										Expression of IL-15 early = advanced
										Synovial membrane IL-1β, IL-6 + TNF-α early = advanced
										SF IL-1β, IL-6 + TNF-α early = advanced
										Synovial membrane IL-21 + IL-2 ↓ early vs advanced
										SF IL-21 + IL-2 early = advanced
Ling et al[64]	2009	169 proteins including: cytokines, chemokines + GFs	Hand and Knee	Serum	Radiographic OA in one or both knees and one or both hands	Initial: 21 Classifying: 19	Initial: 61 Classifying: 66	RCA enhanced antibody-based protein microarray	OA: 10.03 ± 0.31 Controls: 9.88 ± 0.22 (Years)	IL-15 predicted OA at Initial X-ray IL-1α, IL-2, IL-15 + 6Ckine OA ≠ Control IL-15 OA ↑ Control (at Initial + Classifying X-rays)
Livshits et al[47]	2009	CRP, TNF-α + IL-6	Knee	Serum	White females	Year 5: 430 (IL-6: 429) Year 8: 473 Year 15: 322	N/A	TNF-α: High-sensitivity ELISA IL-6: Ultra-Sensitivity ELISA	Year 5, 8 + 15	TNF-α≠ association with RKOA
										IL-6 = association with RKOA
										IL-6 = association with the development of RKOA
Botha- Scheepers et al[57]	2007	TNF-α, IL-1β, IL-1Ra + IL-10	Knee	Whole Blood	Symptomatic knee OA in at least one knee at baseline	86	N/A	ELISA	2 yr	↑ TNF-α (Highest quartile) 6 ×↑ Risk of JSN progression
										↑ IL-10 (Highest quartile) 4 ×↑ Risk of JSN progression
										IL-1β + IL-1Ra ≠ Association with risk of JSN progression
										↑ IL-10 (ex vivo production with LPS stimulation) = ↑ Knee OA progression
Doss et al[49]	2007	IL-6	Knee + Hip	Serum + SF	End-stage OA (Hip or Knee)	49 (Knee: 32, Hip: 17)	N/A	ELISA		16% OA ↑ IL-6 vs 84% OA (Possible sub-groups)
										IL-6 SF = in Knee vs Hip OA, age, sex, stage of disease or course
Riyazi et al[56]	2005	TNF-α, IL-1β, IL-1Ra, + IL-10	Hand, Spine, Hip or Knee	Whole Blood	OA at multiple sites	305	137	ELISA	N/A	↑ IL-1β + IL-1Ra + ↓ IL-10 (ex vivo production with LPS stimulation) = ↑ Multiple site OA familial risk
										↑ TNF-α (ex vivo production with LPS stimulation) ≠↑ OA risk
Phenninx et al[61]	2004	IL-6, CRP, TNF-α, IL-6sR, IL-2sR, TNF-sR1, + TNF-sR	Knee	Serum	Over-weight, older (≥60 yr) + knee OA	274	N/A	ELISA	N/A	↑TNF-sR1 and TNF-sR2 = ↑ WOMAC (Physical Function)
										↑IL-6 = ↓Walking speed
										↑ TNF-sR = ↑ Pain, Stiffness + KL
										IL-1 ≠ association with KL or WOMAC (Physical Function)

ACR: American College of Rheumatology; Adv: Advanced; CLIA: Chemiluminescent enzyme immunoassay; COMP: Cartilage oligomeric matrix protein; CRP: C Reactive protein; ELISA: Enzyme link immunosorbent assay; GF: Growth factor; HGF: Hepatocyte growth factor; hsCRP: High-sensitivity C reactive protein; ICRS: International cartilage repair society; IFN: Interferon; IL: Interleukin; IL-1Ra: IL-1 Receptor antagonist; IP-10: Interferon-γ inducible protein-10; JKOM: Japanese knee osteoarthritis measure; JSN: Joint space narrowing; KL: Kellgren-lawrence grading; LIF: Leukemia inhibitory factor; LPS: Lipopolysaccharides; MCP: Monocyte chemoattractant protein; MIP: Macrophage inflammation protein; NGF: Nerve growth factor; NRSpain: Numerical pain rating scale; OA: Osteoarthritis; PCR: Polymerase chain reaction; RA: Rheumatoid arthritis; RCA: Rolling circle amplification; RKOA: Radiographic knee osteoarthritis; SF: Synovial fluid; sR: Soluble receptor; TNF: Tumor necrosis factor; VAS: Visual analog scale; VEGF: Vascular endothelia growth factor; WBC: White blood cell; WOMAC: Western ontario mcMaster university osteoarthritis index.

Table 2 Classification of cytokines as biochemical markers in osteoarthritis

Cytokine	BIPEDS classification
IL-6	D, P
IL-1β	B, E
TNF-α	B, E
IL-15	B, D
IL-18	D
IL-10	P
IL-2	D
VEGF	B
IL-7	D

B: Burden of Disease; D: Diagnostic; E: Efficacy of Intervention; I: Investigative; P: Prognostic; S: Safety; TNF: Tumor necrosis factor; VEGF: Vascular endothelial growth factor.