In keeping with the results from experimental animal studies [12]–[16], we further hypothesized that hookworm co-infections with A. lumbricoides and/or S. mansoni would significantly alter the immune responses to crude hookworm antigen extracts, resulting in reduced Th2-type responses (IL-4, IL-5, IL-13), a reduced inflammatory response (e.g., lower TNF-α secretion), and an increase in the production of regulatory cytokines (e.g., IL-10). This evidence concerns the gene TNF and coinfection.