On the other hand, qPCR results of genes coding for IL-1α, IL-6, IL-8 and VCAM-1 confirmed no activation by S. suis alone, an intermediate upregulation by swH1N1 infection but a significant increase when cells were co-infected with both pathogens (Figure 4 and Additional file1: Table S3). The gene discussed is CXCL8; the disease is infection.