What causes bartholin's cyst? can decreased immune system cause?

Obstruction...: The bartholin's glands are located on each side of the vaginal opening. Sometimes the openings of these glands become obstructed, causing fluid to back up into the gland. The result is relatively painless swelling called a bartholin's cyst. At times, the fluid within the cyst may become infected, resulting in an abscess. Immune issues could increase risk of cyst getting infected.

Bartholin's cyst: Bartholin's cyst is an abscess formation when the small opening (duct) of one of the bartholin's glands (on each side of the vaginal opening) gets blocked with fluid accumulation and subsequently becomes inflamed and infected. Decreased immune response may precipitate recurrence of this problem.