Table 1 Coefficients of the 23 inflammatory biomarkers for the first 6 components of the rotated Principal Component Analysis, WHICAP (n = 1,743).

Inflammatory functions	Biomarker	PC-1	PC-2	PC-3	PC-4	PC-5	PC-6
Pro-inflammatory	MIP-1β	0.80	− 0.03	− 0.04	0.13	0.10	0.04
	IL-1β	0.79	0.37	0.19	0.08	0.05	− 0.18
	TNF-α	0.77	0.02	0.08	0.03	0.07	0.28
	MCP-1	0.67	− 0.001	− 0.07	− 0.31	0.18	− 0.12
	IL-6	0.65	0.04	0.63	0.09	0.02	− 0.10
	IP-10	0.34	0.06	0.01	− 0.17	− 0.42	0.38
	VEGF	0.32	0.19	0.25	− 0.003	0.29	0.40
	RANTES	0.25	− 0.04	− 0.06	− 0.01	0.53	− 0.02
	Eotaxin	0.20	− 0.01	− 0.02	− 0.71	0.25	0.19
	GRO	0.10	− 0.02	− 0.10	0.72	0.24	0.09
	IL-12p70	0.10	0.87	0.16	− 0.01	− 0.04	0.01
	CRP	0.09	− 0.01	− 0.04	0.43	− 0.02	0.35
	PDGF-AA	0.08	− 0.09	0.01	− 0.03	0.78	0.09
	IL-17A	0.02	0.86	0.18	− 0.03	− 0.06	0.02
	IL-7	− 0.10	0.78	0.14	− 0.01	0.07	0.06
Pro- and anti-inflammatory	TGF-α	0.35	0.18	0.49	− 0.08	0.12	0.39
	GM-CSF	0.29	0.71	0.16	0.07	− 0.09	− 0.16
	Fractalkine	0.11	0.82	0.11	− 0.05	− 0.08	0.03
Anti-inflammatory	IL-1RA	0.78	0.13	0.19	− 0.05	0.07	0.13
	IL-10	0.14	0.34	0.82	− 0.03	− 0.04	0.003
	IL-13	0.03	0.30	0.87	− 0.05	− 0.05	− 0.02
	IL-4	− 0.01	0.10	0.93	− 0.06	− 0.04	− 0.03
	MDC	− 0.06	− 0.08	− 0.07	0.07	0.003	0.68

Principal Component (PC) scores were computed as the linear combination of the 23 inflammatory biomarkers weighted by rotated PCA coefficients. PC-1 was used for the main analysis. It explained 17.1% of the variance of all biomarkers and identified a pro-inflammatory profile with positive loadings for 20 out of 23 markers and specifically high loadings for pro-inflammatory biomarkers (e.g., MIP-1β, IL-1β, TNF-α, MCP-1, and IL-6). Markers with moderate to high contribution to PCs (coefficients >|0.20|) are indicated in bold. PC-2 explained 16.3% of the variance of all biomarkers; PC-3, 14.0%; PC-4, 6.1%; PC-5, 6.0%; and PC-6, 5.5%. Inflammatory biomarkers are classified based on their main functions reported in the literature: pro-inflammatory, anti-inflammatory, or both pro- and anti-inflammatory for biomarkers exhibiting both properties depending on the context of their expression and the cellular environment.

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