CD4 and Immunodeficiency: However, it is more likely a reflection of the association between the higher inflammatory activity with a decline in immune deficiency (neopterin vs. CD4 count: r = −0.558; p < 0.0001; Il-6 vs. CD4 count: r = −0.435; p = 0.00012; IFN-γ vs. CD4: r = −0.271; p = 0.02), coupled to the influence of inflammatory activity on IDO activity (Table 4).