Does this happen to both sides and does it happen only with immunoglobulin or also with other infusions including saline? Leakage of fluid from the glands of the breast is called galactorrhea. There are two reasons that it might happen with immunoglobulin infusions and be more likely on both sides. First is that some other medicine is being given with the immunoglobulin (?steroids, calming medicine, medicine to help settle the stomach)–there are a few that can cause galactorrhea and it might happen only after she gets that medicine and not other times. Second is that there is a huge protein load with immunoglobulin and this might displace some medicine/hormones that are protein bound. I cannot immediately think of any, but the point is to look at other things as well as the “primary” medicine being infused.
Leakage from the breast glands, if this is what this is, is increased if one has a high level of prolactin–the hormone used to let milk “come down”. There are reports of autoimmune problems altering the prolactin pathway including antiprolactin antibodies in lupus. If there is leakage at other times or from both nipples, the person probably should have the prolactin level tested. FYI, this can happen in men or women, but is more likely in women because women’s bodies are already relatively prepped for the potential to make breast fluid. We are just more advanced! Ha.
The breasts are pretty self contained on the surface of people and the port catheter should be intact and separate. People can get holes in the catheter and there is a tiny, tiny chance that a hole could cause leakage into a breast duct. This would have to be only in the breast on the side where the catheter is located. This could be detected with a line study using fluoroscopy or with infusing something that one could see (such as a colored fluid) or detect. Before removing and replacing a port, it is probably worth doing a “line study” where a tiny amount of dye that can be seen by an x-ray test is put into the catheter and the radiologist uses a low level of x-rays (fluorscopy) to see if there is leakage as the fluid/dye is given through the port.