A 25-year-old male with known selective IgA deficiency presents to the emergency department with dyspnea, hypotension, and generalized urticaria shortly after receiving a blood transfusion. Which of the following is the most likely cause of his reaction?
A 2-year-old boy with transient hypogammaglobulinemia of infancy (THI) is being evaluated in follow-up. His parents report a significant reduction in infections, and recent lab results show normal IgG levels for his age. Which of the following correctly explains why this condition resolves with time?
A 12-month-old girl is being evaluated for recurrent mild respiratory infections since she was 6 months old. Laboratory workup shows low serum IgG with normal IgA and IgM levels. Her B-cell and T-cell counts are normal, and her growth and development are on track. Her immunization records indicate normal vaccine responses. Which of the following would be the most appropriate next step in management?
Patient: 10-month-old male Presenting Complaint: Recurrent ear and respiratory infections over the past 4 months History of Present Illness: The child’s mother reports recurrent ear infections, sinus infections, and two episodes of bronchitis since the age of 6 months. The infections typically resolve with antibiotics, but they seem to recur every 3 to 4 weeks. He has not had any severe infections, hospitalizations, or weight loss. His appetite is good, and he is meeting developmental milestones. The mother denies any history of diarrhea, skin abscesses, or opportunistic infections. The child has no known allergies and is up to date on vaccinations. He recently had a mild cold with runny nose and cough, which resolved without complications. Past Medical History: • Full-term birth, no complications • No significant illnesses before 6 months of age Family History: • No family history of primary immunodeficiencies or recurrent infections Physical Examination: • Vital signs: Normal • Growth and development: Normal for age (weight and height in the 50th percentile) • ENT: Mild erythema of the right tympanic membrane (acute otitis media) • Chest: Clear to auscultation • Skin: No rashes or lesions Laboratory Investigations: • Serum IgG: Low for age (below the 10th percentile) • Serum IgA and IgM: Normal • B-cell and T-cell counts: Normal • Vaccine response: Adequate response to tetanus and pneumococcal vaccines • Complete blood count: Normal with no signs of neutropenia What is the most likely diagnosis?
24 year-old African-American woman comes to clinic with dyspnea on exertion and nonproductive cough. CXR shows diffuse interstitial infiltration with bilateral ill-defined hazy airspace opacities. CT scan of the lungs show bilateral patchy and ground-glass opacities and tree-in-bud nodular opacities. Laboratory results show normal levels of circulating B cells, very low serum levels of IgG and IgA and elevated levels of serum IgM levels. You diagnosed her pneumonia is due to pneumocystic jirovecii and started her on antibiotics. Her laboratory report should make you think of
A 30-year-old woman presents with a history of recurrent, non-invasive infections affecting her skin, nails, and oral mucosa. Laboratory tests reveal a defect in T-cell function, while her B-cell function remains intact. Which of the following conditions is the most likely diagnosis?
A 6-year-old boy with a confirmed diagnosis of X-linked agammaglobulinemia has recurrent respiratory infections despite prophylactic antibiotics. What is the most appropriate long-term treatment to manage his condition?
A child with XLA has been managed with immunoglobulin replacement therapy but still experiences occasional infections. His parents are curious about other aspects of his immune function. Which of the following immune functions remains relatively intact in patients with X-linked Agammaglobulinemia?
A young boy diagnosed with XLA is now on regular immunoglobulin replacement therapy. His parents ask about the implications of this diagnosis for his siblings. What is the inheritance pattern of X-linked Agammaglobulinemia, and what is the risk for the siblings of an affected boy?
A 1-year-old boy presents with a history of recurrent pneumonia and sinus infections. Laboratory findings show very low serum levels of IgG, IgA, and IgM. Flow cytometry shows an absence of CD19+ B cells. Which of the following tests would confirm the diagnosis of X-linked agammaglobulinemia?
