You are seeing a 13-year-old boy with fatigue, weight loss, night sweats, and splenomegaly. Peripheral blood shows anemia, thrombocytosis, and leukocytosis (300,000/mm3). What is this patient's most likely diagnosis?

Correct Answer: C

Rationale: The correct answer is C: Chronic myeloid leukemia (CML). This is a likely diagnosis due to the presence of fatigue, weight loss, night sweats, splenomegaly, anemia, thrombocytosis, and leukocytosis with an elevated white blood cell count. CML is characterized by the Philadelphia chromosome, resulting in the BCR-ABL fusion gene. This gene leads to uncontrolled proliferation of myeloid cells, causing the symptoms seen in this patient. Leukemoid reaction (A) is a reactive increase in white blood cells, usually in response to an infection. Acute lymphoblastic leukemia (B) typically presents with symptoms in children but is more commonly associated with lymphoblasts in the peripheral blood. JMML (D) is a rare myelodysplastic disorder in children characterized by monocytosis and a specific genetic mutation.

Correct Answer: D

Rationale: The correct answer is D: Kruskal-Wallis test. Since the LOS data is not normally distributed, parametric tests like Student's t test and ANOVA are not appropriate. The Kruskal-Wallis test is a non-parametric test used to compare three or more independent groups when the data is not normally distributed. It ranks the LOS values across the three central line types and tests whether there are differences in medians. The Wilcoxon-Mann-Whitney test (choice C) is used for comparing two independent groups, not three. Therefore, it is not the appropriate test in this scenario.

Correct Answer: B

Rationale: Correct Answer: B Rationale: 1. Autologous hematopoietic stem cell transplantation should be used when it can provide a meaningful survival benefit over chemotherapy. 2. The most common cancers it is used for include neuroblastoma, responsive brain tumors in young children to avoid/minimize early radiation therapy, and relapsed lymphoma. 3. This choice aligns with the current guidelines and evidence-based practice in utilizing autologous stem cell transplantation for specific cancer types to improve outcomes. Summary of Other Choices: A: Incorrect. It is not necessary to use autologous stem cell transplantation solely for high-dose therapy. The listed cancers are not the most common indications for this procedure. C: Incorrect. The statement about the graft-versus-tumor effect is misleading, and the listed cancers are not the most common ones treated with autologous stem cell transplantation. D: Incorrect. Autologous stem cell transplantation is not used to shorten treatment or avoid extensive chemotherapy. The listed cancers

Correct Answer: B

Rationale: The correct answer is B: Leukocyte adhesion deficiency (LAD) Type II. This diagnosis is supported by the patient's history of recurrent bacterial infections, leukocytosis, neutrophilia, and the Bombay blood group. LAD Type II is characterized by a defect in the CD18 integrin molecules, leading to impaired leukocyte adhesion and migration to sites of infection. The Bombay blood group is due to the absence of H antigen, which is also seen in LAD Type II. A: Chediak-Higashi syndrome is characterized by recurrent infections, albinism, and peripheral neuropathy, not leukocyte adhesion deficiency. C: CD18 deficiency is actually another term for LAD Type I, not LAD Type II. D: Griscelli syndrome presents with silvery hair and immunodeficiency, but does not involve leukocyte adhesion deficiency.

Correct Answer: C

Rationale: The correct answer is C because T-cell numbers in infants are indeed higher than in adults. This is due to the active development of the immune system in infants, leading to a higher proportion of T-cells. A is incorrect because NK-cell numbers in infants are actually higher at birth and decrease with age. B is incorrect because B-cell numbers are lower at birth and increase with age. D is incorrect because infants do not have low lymphocyte counts; their immune system is actively developing, leading to higher lymphocyte counts compared to adults.