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 most likely diagnosis for this 13-year-old boy presenting with fatigue, weight loss, night sweats, splenomegaly, anemia, thrombocytosis, leukocytosis (300,000/mm3) is Chronic Myeloid Leukemia (CML). 1. Presence of anemia, thrombocytosis, and leukocytosis is characteristic of CML. 2. CML typically presents with splenomegaly. 3. Age of onset (13 years) is within the typical range for CML. 4. The Philadelphia chromosome (t(9;22)) is present in most cases of CML, aiding in diagnosis. 5. Leukemoid reaction (A) is a reactive increase in white blood cells, not a primary neoplastic disorder. 6. Acute lymphoblastic leukemia (ALL) (B) typically presents with bone pain, lymphadenopathy, and CNS symptoms in children. 7

Correct Answer: D

Rationale: The correct answer is D: Kruskal-Wallis test. This non-parametric test is used to compare the medians of three or more independent groups when the data is not normally distributed, as in this case with LOS. It is an extension of the Wilcoxon-Mann-Whitney test, which compares two groups. The Kruskal-Wallis test assesses whether the medians of the groups are equal or different by ranking all observations, calculating the sum of ranks for each group, and then comparing these sums. It is appropriate here because it allows for comparison of central line types without assuming normality. The other choices (A: Student's t test and B: ANOVA) require the data to be normally distributed, which is not the case in this scenario. Choice C: Wilcoxon-Mann-Whitney test is for comparing two groups, not three or more.

Correct Answer: B

Rationale: The correct answer is B because autologous hematopoietic stem cell transplantation should be used when it can provide a survival benefit over chemotherapy. This approach is particularly beneficial for certain cancers such as neuroblastoma and relapsed lymphoma. - Choice A is incorrect because the indication for autologous transplantation is not solely based on the need for high-dose therapy, but rather on providing a meaningful survival benefit over chemotherapy. The listed cancers are not the most common ones treated with this approach. - Choice C is incorrect because the graft-versus-tumor effect is actually desired in some cases of autologous transplantation, and the listed cancers are not the most common ones treated with this approach. - Choice D is incorrect because the purpose of autologous transplantation is not to avoid extensive chemotherapy but to provide a survival benefit. The listed cancers are not the most common ones treated with this approach.

Correct Answer: B

Rationale: The correct answer is B: Leukocyte adhesion deficiency (LAD) Type II. This patient's symptoms of recurrent bacterial infections, leukocytosis, neutrophilia, short stature, and Bombay blood group (lack of H antigen) are characteristic of LAD Type II. In LAD Type II, there is a defect in fucose metabolism, leading to impaired leukocyte adhesion and migration, causing immune dysfunction. Chediak-Higashi syndrome (A) presents with oculocutaneous albinism, recurrent infections, and giant granules in leukocytes. CD18 deficiency (C) is a type of LAD characterized by mutations in the CD18 gene causing impaired integrin function. Griscelli syndrome (D) presents with silvery hair, immunodeficiency, and neurological deficits, not matching this patient's symptoms.

Correct Answer: C

Rationale: The correct answer is C: T-cell numbers in infants are higher than in adults. This is because infants have a relatively higher proportion of T-cells compared to adults due to their underdeveloped immune system. T-cell numbers decrease with age as the immune system matures and adapts to the environment. Rationale: 1. T-cells play a crucial role in the immune response, especially in infants who rely heavily on cellular immunity. 2. NK-cell numbers do not follow the pattern described in option A, as they are important in early immune responses. 3. B-cell numbers do not decline with age as stated in option B, as they are responsible for antibody production throughout life. 4. Option D is incorrect as infants actually have higher lymphocyte counts compared to adults due to their developing immune system.