infectious diseases
Factors Facilitating Microbial Invasion
Defects in Host Defense Mechanisms
Two types of immune deficiency states affect the host’s ability to fight infection: Primary Immunodeficiencies None Secondary Immunodeficiencies None Primary immune deficienciesare genetic in origin;>100 primary immune deficiency states have been described. Most primary immune deficiencies are recognized during infancy; however, up to 40% are first recognized during adolescence or adulthood. Acquired immune deficienciesare caused by another disease (eg, cancer, HIV infection, chronic disease) or by exposure to a chemical or drug that is detrimental to the immune system. Defects in immune responses may involve Cellular immunity Humoral immunity Phagocytic system Complement System None Cellular immunity deficiencies None Humoral immunity deficiencies None Phagocytic cell defects None Complement deficiencies None 