CD4 and colorectal carcinoma: We explored the correlation of BMI-associated differential flora with immune cells and immune-related genes and found that in overweight groups of CRC patients Clostridium IV had significant positive correlations with Macrophages M2 and T cells regulatory (Tregs) and significant negative correlations with Dendritic cells activated and T cells CD4 memory activated (shown in Fig. 4C) and a significant negative correlation with the immune activation gene ULBP1 (see Additional file 4: Figure S4).