The Quizzes about Immunology – Part 3 (end)

Since a false-positive result is possible in the screening test in the previous vignette, the physician orders a confirmatory test. Which of the following best describes the standard confirmatory test, and what this test checks for, respectively?

An 8-month-old male infant with a history of chronic diarrhea, otitis media, and several episodes of pneumonia presents to your clinic with gingivostomatitis (due to herpes simplex virus) and oral candidiasis (thrush). You immediately order an x-ray and a blood workup. X-ray and laboratory blood analysis reveal the absence of a thymic shadow and absence of B lymphocytes, respectively. History taken from the infant’s mother reveals a rash evident at birth. Which of the following diseases is most likely present in this infant?

A 5-year-old child arrives at the emergency department minutes after being bitten by a black widow spider. You immediately inject gamma globulin in the form of an antivenom. This type of immunization is referred to as which of the following?

A patient with an increased susceptibility to viral, fungal, and protozoa infection would be expected to have a deficiency in which of the following cell types?

While walking through a field, a 28-year-old woman is stung by a bee. Within 10 minutes, she has asthmatic-like symptoms. This type of hypersensitivity reaction can be correctly characterized by which of the following sequence of steps?

Findings of IgG antibodies to core antigen, antibodies to e antigen, and antibodies to surface antigen in a hepatitis B patient reflects which of the following?

A 15-year-old male is rushed to the emergency room with a temperature of 103°F, severe headache, and stiff neck. Upon physical examination, a petechial rash is observed all over his body. Suspecting meningitis, the physician orders a lumbar puncture, revealing gram-negative diplococci (Neisseria meningitidis) on Gram stain. The physician wishes to use a more sensitive test to confirm this as the causative agent. Which of the following tests combines features of gel diffusion and immunoelectrophoresis and is applicable only to negatively charged antigens?

A 21-year-old female presents to the emergency room with a high fever, hypotension, and a diffuse, macular, sunburn-like rash that is desquamating. She is also vomiting, has profuse diarrhea, leukocytosis, thrombocytopenia, and elevated BUN and creatinine levels. History from her roommate reveals that these symptoms started soon after the patient began packing her nose to stop chronic nose bleeds. Suspecting S. aureus, a nasal swab specimen is obtained and sent to the laboratory. Which of the following rapid tests will be ordered and depends on the presence of protein A on certain strains of S. aureus?

A 50-year-old building contractor arrives in your office complaining of abdominal pain that has increased in severity over the past 3 months. He has noticed melenic stool. Ordering a sigmoidoscopy, a 10-cm mass is visualized in the transverse colon. Surgery is immediately done and the tumor excised. As part of the patient’s postsurgical follow through of this resected carcinoma of the colon, blood is obtained and sent to the laboratory to monitor levels of the tumor marker known as CEA. Which of the following tests involves the measurement of very small quantities of CEA through competition of radiolabeled and unlabeled antigen for the same limited amount of antibody?

A 13-year-old male arrives at his doctor’s office with a severe sore throat and very high fever. On physical examination, the physician observes his pharynx to be inflamed with a significant exudate along with tender cervical lymph nodes. Laboratory tests reveal a leukocytosis. Suspecting Group A β-hemolytic Streptococcus pyogenes, a throat swab and culture are obtained. Using a rapid diagnostic kit recently obtained, the physician decides to test the specimens himself. This test involves inert particles that are sensitized with either antigen or antibody. Which of the followin tests is used extensively to detect microbial antigens rapidly (5 minutes or less)?

A 7-month-old baby who is failing to thrive is brought into a neighborhood clinic. History reveals that the baby’s mother died of AIDS 2 months ago. Blood is obtained and sent to the laboratory to check for HIV infection. The physician orders a test whose detection system is based on enzymatic activity. Which of the following tests is a heterogeneous immunoassay?

An 18-year-old male patient with acute lymphocytic leukemia fails all standard chemotherapies. Cells from an HLA-nonidentical donor are used to perform a bone marrow transplant. Prior to transplantation, the patient is given broad-spectrum antibiotics and an immunosuppressive regimen. Within 2 to 4 weeks, lymphocyte and granulocyte numbers begin to rise, confirming bone marrow cell engraftment. However, 1 month later, the patient develops diarrhea, jaundice, and a severe maculopapular rash. Physical examination reveals hepatosplenomegaly. Which of the following is most likely occurring?

A 27-year-old male patient (blood group O) arrives at the emergency room with a massive intestinal bleed (hematochezia). Within hours he has lost half of his blood volume, and you decide to transfuse. Due to human error, you transfuse blood group AB into him and within minutes he develops a fever, chills, dyspnea, and a dramatic drop in blood pressure. This reaction is most likely due to which of the following?

During a clinic office visit, a 35-year-old male stockbroker shows signs of excessive nervousness and irritability and complains that the office is too hot. History and physical examination reveals the presence of a goiter and exophthalmia. Laboratory analysis of his blood reveals high antibody titers against the thyroid-stimulating hormone (TSH) receptor. Which of the following is the most likely diagnosis?

A 9-year-old female with a recent history of weight loss and vision problems arrives at the hospital. Soon after, it is determined that she has low blood glucose, and autoantibodies against β cells are detected in her serum. Which of the following is the most likely diagnosis?

A 35-year-old woman with fever, weight loss, fatigue, and painful joints and muscles presents to her physician’s office. The physician notes that she has marked photosensitivity and a rash on the cheeks and over the bridge of her nose. Laboratory tests reveal anemic conditions and the presence of anti-DNA antibodies. Which of the following is the most likely diagnosis?

A preschool boy is diagnosed with an immunodeficiency characterized by impaired T-cell activation. The defect is caused by a genetic alteration of a membrane protein whose cytoplasmic tail is involved in signaling associated with TCR recognition of peptide antigen in the context of MHC. Which of the following proteins does NOT fit this description?

A 1-month-old infant with a bright red rash and purulent conjunctivitis is admitted to the hospital. Examination revealed eosinophilia, low lymphocyte count, and no thymic shadow. Lymphnodes were enlarged and opportunistic infections noted. The diagnosis was a form of SCID termed Omenn syndrome, an autosomal recessive form of SCID. Mutations in which of the following would explain this disease?

Class-I MHC-restricted CD8+ T cell (CTL) responses to tumors can be demonstrated in patients with various types of tumors, yet most of these tumors do not express costimulatory molecules. Which mechanism most likely explains how naïve CD8+ T cells specific for antigens expressed by these tumors are activated and differentiate into CTLs?