A 21 yo man with a long medical history presented himself to a physician with an abnormal blood test results. When he was 5 yo he already elicited history of easy bruising. His brother also died very young from intracranial hemorrhage. Family history revealed that his maternal grandfather died after undergoing surgery due to severe bleeding. His Lab findings were as follows: Platelet count $=290,000 / \mathrm{mm}^{2}$ Bleeding time $=7$ minutes Prothrombin time $\langle P T)=11$ seconds Partial thromboplastin time $\langle P T T\rangle=59$ seconds Fibrin split - products $=22 \mu \mathrm{g} / \mathrm{mL}$ Hematocrit \& WBC = both normal \[ \begin{array}{c} \left(\text { normal }=150,000-350,000 / \mathrm{mm}^{3}\right) \\ (\text { normal }=3.5-10.5 \text { minutes) } \\ \text { (normal }=10-12 \text { seconds) } \\ \text { (normal }=20-30 \text { seconds) } \\ \text { (normal }=8-40 \mu \mathrm{g} / \mathrm{mL} \text { ) } \end{array} \] He was informed that he had a "blood disease" and would require close medical attention. In the past two years, his health has deteriorated. He experiences easy fatigability, sore throat, and swollen lymph nodes in the neck and groin. This was followed a few weeks later by a diarrheal illness and severe parasitic pneumonia that required intensive antibiotic treatment and suffered a $10 \mathrm{~kg}$ weight loss. Three months ago, he noted the appearance of silver-dollar-sized purple blotches on his skin that have still not gone away. In the past week he has progressively weakened, suffering from chills, weakness, and a high fever that has left him bedridden. Laboratory studies reveal a white blood cell count of 2.8 (2,800 WBCs / $\mathrm{mm}$; normal range is 4,500 to $11,000 \mathrm{WBCs}$ ) $\mathrm{mm}^{2}$ ) with a markedly reduced number of $\mathrm{T}$ - helper cells. Questions: 1. Why does the patient bleed so easily? What is significant in his family history? Show a pedigree to explain your answor. (30 points) 2. Why is the PTT elevated? Why isn't the PT elevated? Exactly what is assessed by these tests? $(20$ points) 3. What has been the primary cause of the patient's poor health in the past two years? Is his iliness of the past two years related in any way to the "blood disease"? (20 points)

pls help me answer number 3

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