56.下列何者不是急性肺炎發生時迅速誘發防禦細胞趨化作用與執行清除的機制？
(A)肺臟具雙重血液循環系統與密布的微血管
(B)炎症細胞可藉由滲出作用，迅速由postcapillary venules穿過血管而進入組織間隙與肺泡腔內
(C)活化多種肺臟巨噬細胞的功能
(D)因肺臟微血管大量嗜中性球，可迅速對外來感染因子進行反應

節錄一段原文書給大家參考

Pathologic Basis of Veterinary Disease ,6th, page 513.

Before reviewing how inflammatory cells are recruited in the lungs, three significant features in pulmonary injury must be remembered:

(1) Leukocytes can exit the vascular system through the alveolar capillaries, unlike in other tissues, where postcapillary venules are the sites of leukocytic diapedesis (extravasation);

(2) the intact lung contains within alveolar capillaries a large pool of resident leukocytes (marginated pool); and

(3) additional neutrophils are sequestered within alveolar capillaries within minutes of a local or systemic inflammatory response.

These three pulmonary idiosyncrasies, along with the enormous length of the capillary network in the lung, explain why recruitment and migration of leukocytes into alveolar spaces develops so rapidly.  

回到題目我會有的一些comment包括

(B) 可能是想強調 diapedesis (血球滲出) 亦可發生於肺泡微血管，書上是也沒有提到肺臟微血管後小靜脈與 migration 的關係

(C) PAM 的吞噬清除、抗原呈現、媒介細胞激素與趨化因子的功能應該沒什麼問題

(D) 我也是寫到這題才知道肺泡微血管是個大型邊緣池，雖然常理推測原文的 leukocytes 應即為嗜中性球，但我找不到更直接的教科書支持

B. 應該怎麼改？

求解～