One of the first things that we are told to do, when diagnosed with Lupus, is to reduce our intake of protein (such as red meats etc.). If our kidneys are already taxed by this disease, reducing protein in our diet can help to relieve some of the stress on our kidneys. Some say that taking large doses of Vitamin C helps (since vitamin C is filtered and "wasted" through the kidneys). Also, increasing carbohydrates is suggested. It is thought that, by doing this, it will also reduce the catabolism of proteins and prevent ketosis. Also, a regular vegetarian diet, which is high in complex carbohydrates, has also been suggested.
None of these suggestions are provided by doctors, however. So, it is important that you discuss these with your doctor before you decide to use them.
Perhaps someone else will be along with more information for you. I do hope that your protein leak is controlled soon.
Peace and Blessings
Look For The Good and Praise It!