Which of the following statements accurately describes the role of dendritic cells in the immune response?

Correct Answer: C

Rationale: Dendritic cells play a critical role in initiating adaptive immune responses by capturing antigens from pathogens, migrating to lymphoid organs, and presenting these antigens to naïve T cells. This activation of naïve T cells by dendritic cells is essential for the adaptive immune system to generate specific immune responses against pathogens. Dendritic cells act as professional antigen-presenting cells, which are specialized to capture, process, and present antigens to T cells, thereby facilitating the activation of T cells and the coordination of adaptive immune responses, such as the production of specific antibodies and the generation of memory T cells.

Correct Answer: B

Rationale: The most effective treatment for addressing the underlying pathophysiology of cystic fibrosis (CF) and preventing disease progression is the use of mucolytic agents, such as dornase alfa. CF is a genetic disorder that leads to the production of thick, sticky mucus in the respiratory tract. This mucus buildup can obstruct airways, lead to recurrent infections, and contribute to pulmonary exacerbations. Mucolytic agents work by reducing the viscosity of the mucus, making it easier to clear from the airways. This helps to improve lung function, reduce the frequency of exacerbations, and slow down disease progression in CF patients. Inhaled corticosteroids may be used for managing airway inflammation, but they do not target the underlying mucus production in CF. Antibiotic therapy is important for treating respiratory infections in CF patients, but it does not address the primary

Correct Answer: A

Rationale: In a patient with suspected pulmonary TB, the most appropriate diagnostic test for confirming the diagnosis is the sputum acid-fast bacilli (AFB) smear and culture. This test involves examining sputum samples under the microscope for the presence of acid-fast bacilli, which are characteristic of Mycobacterium tuberculosis, the bacteria that causes TB. Additionally, culturing the sputum allows for the bacteria to grow in a controlled environment, further confirming the diagnosis. In the given scenario, the patient's symptoms (cough, weight loss, night sweats, hemoptysis), along with chest X-ray findings of upper lobe infiltrates and cavitation, are highly suggestive of pulmonary TB. Therefore, performing a sputum AFB smear and culture is crucial for definitive diagnosis and initiation of appropriate treatment. The other options (Tuberculin skin test, Interferon

Correct Answer: A

Rationale: The patient's presentation with fatigue, pallor, dyspnea on exertion, low hemoglobin level, decreased MCV, and decreased MCHC are all consistent with iron deficiency anemia. Iron deficiency anemia is the most common type of anemia and occurs when there is insufficient iron available for hemoglobin production. The low hemoglobin level results in symptoms such as fatigue and pallor, while the decreased MCV and MCHC indicate microcytic and hypochromic red blood cells, respectively, which are characteristic of iron deficiency anemia. Vitamin B12 deficiency anemia and thalassemia typically present with a different pattern of laboratory findings and clinical manifestations. Sickle cell anemia is characterized by sickle-shaped red blood cells due to a genetic mutation, and the laboratory findings in sickle cell anemia are different from those seen in the patient described in this scenario.

Correct Answer: D

Rationale: The patient is presenting with symptoms and laboratory findings consistent with a paraneoplastic syndrome related to Hodgkin lymphoma. In this case, the fever, chills, generalized malaise, pancytopenia, circulating Reed-Sternberg cells, and bone marrow involvement are all indicative of a paraneoplastic syndrome associated with Hodgkin lymphoma. Paraneoplastic syndromes are a group of disorders that are triggered by an abnormal immune response to a neoplasm, such as Hodgkin lymphoma, leading to various systemic manifestations.