Could there be a relationship between lupus and beta thalassemia minor?

No. Lupus is not related to Alpha or beta thalassemias. The thalassemias cause "intrinsic" anemia, meaning the anemia is due to a problem inside the red blood cells. Lupus is an autoimmune disease and causes "extrinsic" anemia, meaning lupus is acting on the red blood cells from the outside and causing them to be destroyed.