A 4-year-old female child presents with history of recurrent pyogenic bacterial infections and not responding well to antibiotics. An in vitro analysis of the girl’s neutrophil function in specially constructed tubes lined with human endothelium shows a defect in rolling. Which of the following serves as a ligand to bind the molecules on the endothelium that is involved in rolling?

A 16-year-old female has a history of recurrent pyogenic bacterial infections of the skin and soft tissues not responding well to antibiotics. The physician suspects an immunological disorder and orders tests for neutrophil function. Results show production of O2- , H2O2, OH- by neutrophils to be normal and production of HOCl is decreased following stimulation by opsonized bacteria. Which of the following is most likely defective?

Your patient is a four-month-old boy with recurrent hospitalizations because of pneumonia, several episodes of acute otitis media with non-purulent drainage from the ear, and positive bacterial growth in laboratory cultures. His medical history included neonatal sepsis. Laboratory studies: CBC showed marked leukocytosis with a WBC count >40X103/microliter (normal:4-12X103/microliter), predominance of morphologically normal neutrophils and normal numbers of CD19+ and CD3+ cells in the peripheral blood that persisted during this hospitalization despite the antibiotic treatment. DHR and the NBT test is normal. Which of the following is the most likely underlying cause for his recurrent infections?

A 2-month-old boy is admitted to the hospital for workup of a possible immunologic disorder. His history is remarkable for the occurrence of multiple pyogenic bacterial skin infections. PE shows generalized tender lymphadenopathy. Blood tests reveal an elevated ESR and morphologically normal WBC and neutrophilia. NBT test and DHR flow cytometry assay (dihydrorhodamine) is negative. Which of the following is the most likely defect in the child?

A 35-year-old male presents with complaints of a hypopigmented skin lesion on the right forearm, associated with loss of sensation. Physical examination reveals a thickened median nerve, and loss of cutaneous sensation in the area innervated by median nerve. Biopsy of the skin lesion shows numerous granulomas surrounding the skin lesions and nerve endings. Special stains reveal acid fast bacilli (Mycobacterium leprae). Production of which of the following mediators is responsible for the activation of macrophages in the granulomatous response?