although 这个让步状语从句，让步的上面并列主句中的哪个？

HPV seems to be an entirely local mechanism, and, as might be expected, has been shown to persist in the human transplanted lung, although some studies have demonstrated abnormalities, particularly in patients with pulmonary hypertension.

HPV似乎是一种完全局部的机制，正如预期，已证明在人类移植肺中HPV持续存在，51尽管某些研究发现HPV异常，特别是肺动脉高压患者。

HPV缺氧性肺血管收缩

although 这个让步状语从句，让步的上面并列主句中的哪个？

1.如果是“HPV seems to be an entirely local mechanism，although some studies have demonstrated abnormalities, particularly in patients with pulmonary hypertension”。那就是移植前肺动脉高压患者的HPV异常，但移植后HPV正常

2.如果是“HPV has been shown to persist in the human transplanted lung, although some studies have demonstrated abnormalities, particularly in patients with pulmonary hypertension.”也就是移植前肺动脉高压患者移植后HPV异常

谢谢