Immunology Question Set 2

A 4-year-old boy presents with a history of recurrent bacterial infections, including several episodes of pneumococcal sepsis. His two maternal uncles died having the similar complaints. Lab investigations reveal an undetectable level of all serum immunoglobulins. Which of the following is the most likely diagnosis of this patient?

A 52-year-old man comes to the office with the complaint of blood in the urine. He had a mild respiratory illness three weeks ago. Urinalysis reveals numerous red blood cells with RBC casts. A diagnosis of post-streptococcal glomerulonephritis is made. The doctor explains that the treatment is supportive and that the patient needs follow-up visits. Six weeks later, the patient comes to the clinic saying he does not feel well. He complains of malaise and fatigue. On examination, his pulse rate is 98/min, blood pressure is 135/85 mm Hg, the temperature is 98°F, and respiration rate is 16/min. He has a mildly distended abdomen. Blood tests reveal that his creatinine level increased to 3.0 mg/dL from 1.2 mg/dL last month. He was referred to a nephrologist, who diagnosed him with rapidly progressive glomerulonephritis. After starting hemodialysis, his potassium level rises to 7 mEq/dL. The patient needs to undergo a renal transplant. His HLA genotype is A7/A5, B2 /B9, C8/C3. For each locus, the first is the maternal allele, and the second is the paternal allele. Which of the following donors would be the closest match?

A group of scientists is studying the effects of cytokines on the effector cells including leukocytes. They observe that IL – 12 is secreted by antigen-presenting cells in response to bacterial lipopolysaccharide. When CD4+ T-cell is exposed to this interleukin, it will produce the following response:

A 6-month-old male presents to his pediatrician for the evaluation of recurrent bacterial infections. He has a history of a variety of bacterial infections since birth. Physical examination reveals light colored skin with silver hair. You suspect an immunodeficiency disorder and decide to do some investigations. Study of his neutrophils reveals that they contain large cytoplasmic vacuoles. Genetic studies show a mutation in the LYST gene. Which of the following is the most likely diagnosis?

A 1-year-old pale looking boy presents with high-grade fever and ecchymosis for the last 2 weeks. Patient has achieved all developmental milestones on time and has no history of medical illness in the past. Lab investigations reveal: Hemoglobin: 5.5 g/dL (Ref: 11-16 g/dL) WBC: 112,000/mm3 (Ref: 4000-10,000/mm3) Platelets: 15,000 /mm3 (Ref: 150,000-400,000/mm3) ESR: 105/1st hour (Ref: Less than 15/1st hour) The boy is referred to a Hematologist who suspects that the boy might be suffering from neoplastic proliferation immature B cells and decides to do a flow cytometry analysis. Detection of which of the following markers would help confirm his suspicion?

12 year-old-girl presents with episodic shortness of breath and cough. These episodes occur more frequently in spring season when pollens are in abundance. Her mother has similar complaints. Physical exam reveals bilateral wheezes on the chest auscultation. The initial body response to this pollen consists of production of IgM immunoglobulin. However, over time, antigen-specific lgE became predominant. This change from an lgM to an lgE response is caused by which of the following process?

A 52-year-old male is diagnosed with chronic renal failure. He is on hemodialysis. Doctors have advised him for the renal transplant. His HLA genotype is: A7/A5, B2 /B9, C8/C3. For each locus, we have listed the maternal allele first and the paternal allele second. There are several potential donors available for the renal graft. Which of the following donors would be the closest match?

A group of scientists were studying the effects of cytokines on the effector cells including leukocytes. They observed that IL – 12 is secreted by antigen presenting cells in response to bacterial lipopolysaccharide. When CD4+ T-cell is exposed to this interleukin, it will produce the following response:

An 11-month-old boy is brought to the office by his mother because the boy has a rash. On examination his temperature is 100F, pulse is 98/min and respirations are 16/min. There are thin walled fluid-filled blisters that seem to easily rupture. Sample from the lesion site reveals S. aureus. A diagnosis of Scalded Skin Syndrome is made. Which of the following best describes the primary defense mechanism by which the immune system responds to the toxins produced by this organism during the pathogenesis of this disease?

A group of scientists is studying various ways of bacterial reproduction. They come to know that via these processes bacteria also exchange various materials. They are about to study one such method known as bacterial conjugation. Which of the following is an example of a bacterial action that occurs via the process they are studying?

A 12-year-old boy admitted in the ICU suddenly develops hypotension. He was admitted last night due to severe pneumonia and was started on empiric antibiotics. The reports of blood culture are pending. According to the nurse, the patient was doing alright when his blood pressure started to drop suddenly. His blood pressure is 88/58 mmHg, temperature is 103F, pulse is 120/min and respirations of 24/min. You decided to start him on intravenous vasopressors as the blood pressure did not respond intravenous fluids. The intensivist on call arrives and suspects septic shock. What is the mechanism of action of toxin in the pathogenesis of this patient's shock?

A 72-year-old man suffering from a chronic lower UTI started taking clindamycin a week ago and now comes with a fever and severe diarrhea. Which of the following best represents his clinical condition?

You are treating a young man only 25-years of age. The patient is an HIV positive with a nodule on the top of his right foot. The nodule is tanned brown but painless. The patient has no abnormal structure and fever. Patient’s CD4+ T-cell calculation is 20/µL without taking any antiretroviral therapy. His biopsy results indicate blood vessels’ lobular proliferation with overgrown endothelial cells. There are signs of both acute and chronic inflammation on the nodule. This patient lives with one of his friends who have kittens as pets. Tissue stains on the affected area also indicate gram-negative bacilli. Please select the most effective therapy option for lesions from the following.:

A 2-month-old child is brought by her mother to the clinic for her first immunization. Upon physical examination, it is found that the baby is shivering and the body temperature is 39°C. Her mother says that she is constantly crying, irritable and refusing to eat. What is the most appropriate medical intervention in this case?