The nurse is caring for clients on the medical-surgical unit. What action by the nurse will help prevent a client from having a type II hypersensitivity reaction?

Correct Answer: B

Rationale: The correct answer is B because correctly identifying the client prior to a blood transfusion helps prevent a type II hypersensitivity reaction, which occurs when the body attacks its own cells due to mismatched blood types. This action ensures that the client receives compatible blood, reducing the risk of a transfusion reaction. Administering steroids for a positive TB test (A) is unrelated to preventing a type II hypersensitivity reaction. Keeping the client free of the offending agent (C) is more relevant to preventing a type IV hypersensitivity reaction. Providing a latex-free environment for the client (D) is important for preventing a type I hypersensitivity reaction in latex-sensitive individuals, not type II reactions related to blood transfusions.

Correct Answer: B

Rationale: The correct answer is B: Signal propagation in T cells. CD3 is a protein complex found on the surface of T cells that is crucial for T cell receptor signaling and activation. It helps propagate signals within T cells, leading to T cell activation and immune responses. Choice A (Antigen binding) is incorrect as CD3 is not directly involved in antigen binding. Choice C (Signal propagation in B cells) is incorrect as CD3 is specific to T cells, not B cells. Choice D (T cell homing to lymph nodes) is incorrect as CD3 is not responsible for the physical migration of T cells to lymph nodes.

Correct Answer: E

Rationale: Rationale for Correct Answer (E): E: Surgery is the correct answer. Surgery is not typically used as a primary therapy for autoimmune diseases. Autoimmune diseases are usually treated with medications such as immuno-suppressive drugs (A), anti-inflammatory drugs (B), and targeted therapies like anti-TNF (C) and anti-CD20 (D) to manage symptoms and control the immune response. Surgery is only considered in specific cases when other treatments have failed or for complications related to the autoimmune disease. Therefore, surgery is not a standard therapy for autoimmune diseases. Summary of Incorrect Choices: A: Immuno-suppressive drugs like cortisone are commonly used in autoimmune disease treatment. B: Aspirin is an anti-inflammatory drug that can help manage symptoms in some autoimmune diseases. C: Anti-TNF therapy targets specific molecules involved in the immune response in autoimmune diseases. D: Anti-CD20 therapy targets B cells to modulate the immune response in autoimmune diseases.

Correct Answer: E

Rationale: I'm sorry, but the correct answer is not provided in the choices given. Acquired passive immunity refers to the transfer of antibodies from one individual to another. Breast milk, placental transfer, short-term protection, and disease prevention are all characteristics of acquired passive immunity. Therefore, the correct answer is not presented in the options provided.

Correct Answer: D

Rationale: The correct answer is D because all the choices contribute to the vascular instability observed in severe sepsis. A: Systemic release of cytokines like TNF-α and IL-1β leads to vasodilation and increased capillary permeability. B: Complement activation causes inflammation and vasodilation. C: Release of high levels of lipid mediators like prostaglandins and leukotrienes further exacerbates vasodilation and vascular permeability. Therefore, all these mechanisms combined lead to the vascular instability seen in severe sepsis.