What are the criteria needed to characterise multiple myeloma? (Choose one)

Correct Answer: B

Rationale: The correct answer is B: Monoclonal protein in serum or urine. Multiple myeloma is characterized by the presence of abnormal plasma cells in the bone marrow, which produce monoclonal proteins. These proteins can be detected in the blood or urine through electrophoresis. Fever and infection (Choice A) are common symptoms but not specific to multiple myeloma. Elevated platelet count (Choice C) is not a characteristic feature of multiple myeloma. Normal bone marrow (Choice D) is not consistent with the disease, as multiple myeloma involves abnormal plasma cell proliferation in the bone marrow.

Correct Answer: C

Rationale: The correct answer is C because AIDS is caused by the human immunodeficiency virus (HIV), which specifically targets and kills CD4-positive T lymphocytes. These cells are crucial for coordinating the immune response. A, B, and D are incorrect because HIV primarily affects CD4-positive T cells, not B lymphocytes, lymphocyte stem cells, or CD8-positive T cells. This leads to a weakened immune system, making individuals more susceptible to infections and other complications associated with AIDS.

Correct Answer: D

Rationale: The correct answer is D: decreased resistance to Neisseria bacteremia. This is because C6 is a component of the complement system, which plays a crucial role in the immune response against Neisseria bacteria. A deficiency in C6 would impair the ability to effectively combat Neisseria infections. Choice A is incorrect because the deficiency of C6 does not directly affect resistance to viral infections. Choice B is incorrect as hypersensitivity reactions are not specifically linked to C6 deficiency. Choice C is incorrect because there is no direct correlation between C6 deficiency and an increased frequency of cancer.

Correct Answer: B

Rationale: The correct answer is B because helper T cells play a crucial role in activating B cells to produce antibodies. In this scenario, the protein component of the hapten-protein conjugate must be recognized by helper T cells to initiate the immune response. This recognition leads to the activation and differentiation of B cells into plasma cells that secrete anti-hapten antibodies. Choices A, C, and D are incorrect because the focus should be on the protein component, not the hapten or suppressor T cells, for the production of anti-hapten antibodies.

Correct Answer: D

Rationale: The correct answer, D, is not true because class I MHC antigens are primarily found on all nucleated cells, not just B cells, macrophages, and activated T cells. These antigens present endogenous antigens to CD8+ T cells. Choice A is incorrect because class I MHC antigens are not typically assayed using antibody and complement; instead, they are recognized by CD8+ T cells. Choice B is incorrect because identifying class I MHC antigens in the lab usually requires more than a few hours due to the complexity of the process. Choice C is incorrect because class I MHC antigens are controlled by a single gene locus in the major histocompatibility complex.