CXCL8 and obesity due to melanocortin 4 receptor deficiency: Further, adult study participants with overweight/obesity consuming five weekly dinners with cod fillet actually had lower serum concentrations of neopterin (stimulated by interferon-γ during immune activation)(50), with no changes in serum concentrations of TNF-α, IL-8 and monocyte chemoattractant protein 1(51).