A 30-year-old man has a history of heart transplant and is receiving long-term steroids to prevent rejection. The patient is due for routine vaccines. Attenuated vaccines are contraindicated in this patient because the antigen is:

Correct Answer: A

Rationale: The correct answer is A: live and can cause infection. Patients who are immunocompromised, like those receiving long-term steroids after an organ transplant, should not receive live vaccines because the live attenuated organisms in these vaccines can cause infections in individuals with weakened immune systems. Choice B is incorrect because attenuated vaccines are live but weakened, not mutated. Choice C is incorrect because while inactive, attenuated vaccines are not infectious. Choice D is incorrect because attenuated vaccines are not pathogenic; they are attenuated (weakened) forms of the pathogen.

Correct Answer: C

Rationale: The correct answer is C: Complement, clotting, and kinin systems. These are the three main plasma protein inflammatory mediator systems. The complement system helps in inflammation and immune responses, the clotting system is involved in blood coagulation, and the kinin system regulates inflammation and blood pressure. Choice A is incorrect because interferon is not part of the plasma protein inflammatory mediator systems. Choice B is incorrect because the fibrinolytic system is not a primary inflammatory mediator system. Choice D is incorrect because acute phase reactants are not part of the plasma protein inflammatory mediator systems.

Correct Answer: A

Rationale: The correct answer is Vitamin B12. Vitamin B12 deficiency can lead to megaloblastic anemia, a condition characterized by the production of abnormally large and immature red blood cells. Lower extremity paresthesias, such as tingling or numbness, are common neurological symptoms associated with vitamin B12 deficiency. Folate deficiency can also cause megaloblastic anemia but is not typically linked to lower extremity paresthesias. Iron deficiency leads to microcytic anemia, not megaloblastic anemia. Vitamin K deficiency is associated with bleeding tendencies, not megaloblastic anemia or paresthesias.

Correct Answer: D

Rationale: Anemia of chronic inflammation is typically characterized by normochromic (normal hemoglobin content) and normocytic (normal cell size) red blood cells. Choice A, hypochromic and microcytic, is incorrect because hypochromic refers to reduced hemoglobin content and microcytic refers to smaller than normal red blood cells, which are not typically seen in anemia of chronic inflammation. Choice B, hypochromic and macrocytic, is also incorrect as macrocytic refers to larger than normal red blood cells. Choice C, normochromic and microcytic, is incorrect because microcytic red blood cells are smaller than normal. Therefore, the correct classification for anemia of chronic inflammation is normochromic and normocytic.

Correct Answer: B

Rationale: The correct answer is that the person is a sickle cell carrier. In HbAS, 'Hb' stands for hemoglobin, 'A' indicates normal hemoglobin, and 'S' indicates the sickle cell trait. Individuals with HbAS are carriers of the sickle cell trait but do not have sickle cell disease. Choice A is incorrect because having the sickle cell trait means carrying the gene for sickle cell disease. Choice C is incorrect as sickle cell anemia is a different condition where individuals have two copies of the abnormal hemoglobin gene, resulting in the disease. Choice D is incorrect because thalassemia is a separate genetic disorder affecting the production of hemoglobin, not related to the sickle cell trait.