Final answer:
Second degree non-immune mediated ThCy involves a T-cell response and can be caused by factors like activated macrophages, cytokine release, or autoimmunity due to molecular mimicry. These reactions can result in chronic allergic conditions or autoimmune diseases.
Step-by-step explanation:
The causes of a second degree, non-immune mediated Type IV hypersensitivity reaction (ThCy) are diverse, but it typically involves T cells and is not directly caused by antibodies. These reactions can be broken down into several subcategories, including CD4 TH1-mediated and CD8 cytotoxic T lymphocyte (CTL)-mediated responses. In CD4 TH1-mediated reactions, such as in the Mantoux skin test or in contact dermatitis, activated macrophages play a major role in tissue damage upon subsequent exposure to an antigen. Chronic conditions like asthma or allergic rhinitis are associated with CD4 TH2-mediated reactions that involve cytokine release and inflammatory mediators. Additionally, molecular mimicry can cause the immune system to mistakenly attack self-antigens, leading to autoimmunity. This can be seen in diseases like rheumatic fever or Type 1 diabetes, where a destructive inflammatory TH1 response against insulin-producing cells of the pancreas occurs. Secondary causes of immunodeficiencies such as malnutrition, viral infections, or chemical exposures can also contribute to these hypersensitivity reactions.