Eissa M K, Sparks R A, Newton J R
Contraception. 1985 Jul;32(1):87-95. doi: 10.1016/0010-7824(85)90118-0.
Immunoglobulin levels were measured by agar gel single radial immunodiffusion in the serum and cervical mucus of 50 tailed copper IUD users, 20 combined oral contraceptive users and 20 women not using contraception (controls). IgG, IgA and IgM levels were significantly higher in the copper IUD users compared to the other two groups. It is not known whether this was related to the small numbers of bacteria found in the uterine cavity of tailed IUD users or to the foreign body reaction of the device.