Table 2.

Studies evaluating the association of plasma cytokines with radiation-induced lung toxicity

Author year	Patients No.	Endpoint	Cytokines (p value)	Sample handling process
Stenmark 2012[98]	58	≥G2 RP or symptomatic pulmonary fibrosis	IL-8 preRT and at weeks 2 and 4 during RT (p<0.01); TGF-β1 ratios at 2 and 4 weeks during RT/baseline (p=0.41, 0.26).	platelet-poor plasma*
Zhao 2009[99]	165	≥G2 RILT	TGF-β1 ratio at 4-5 weeks during RT/ baseline (p < 0.001).	platelet-poor plasma¶
Kim 2009[89]	34	≥G2 RP	Change of TGF-β1 level during RT (p=0.0001)	platelet-poor plasma§
Zhao 2008[88]	26	≥G2 RILT	TGF-β1 ratio at 4 weeks during RT/baseline (p=0.015)	platelet-poor plasma*
Evans 2006[90]	121	≥G1 RP	TGF-β1 ratio at end-RT/baseline (p < 0.001).	platelet-poor plasma*
Hart 2005[97]	55	SRILT	IL-8 preRT (p < 0.005).	platelet-poor plasma*
Jaeger 2004[95]	68	≥G2 RP	TGF-β1 ratio at 4-6 weeks during RT/ baseline (p=0.01 inverse relation)	plasma‖
Novakova-Jiresova 2004[96]	46	Symptomatic RP	TGF-β1 level (p>0.05)	plasma†
Fu 2001[87]	103	Symptomatic RILT	TGF-β1 level end-RT (p=0.007)	platelet-poor plasma*
Anscher 1998[83]	73	Symptomatic RP	TGF-β1 level end-RT (p<0.05)	platelet-poor plasma*

^*¶§These studies used procedures of plasma preparation to minimize the platelet contamination or degradation, by using enough gravities, controlling time and temperature of blood setting before centrifuge, avoiding platelet contamination by using top layer of plasma.

^{‖ and †}: Plasma samples may have been contaminated by platelets, as they used 1200 or 1000g which was not enough to remove the platelets in plasma supernatant.