Table 3.

Step  1—Heckman model: parameters estimation of correlation between erythema and proinflammatory cytokines levels.

Variable	Coefficient	Standard Error	P value
Probit model for the inflammatory markers
Intercept	−1.648	0.352	2.87e − 06
Erythema	2.065	0.468	1.01e − 05
σ 2 b	3.792