Hi Manal,
If an intermedia stops transfusing, the bone marrow will eventually become active again. This is why when transfusion dependent intermedias are put on fetal Hb inducers such as hydroxyurea, transfusions are stopped several months in advance so that the bone marrow will become active again, making it possible to produce more HbF. This is also why there have been so few tests done on majors using HbF inducers. It is extremely hard to convince a major to stop transfusing for several months in order to try an HbF inducing drug. This is also why the main study done to date using majors was in Algeria where finding under-transfused patients was not difficult. (By the way, that study had very positive results for majors and suggested that hydroxyurea might be a low cost alternative to transfusions in poor areas of the world).
Miltswifey is exactly right about why she was able to stop transfusing for 5 years. Splenectomy is often used as a treatment in intermedias because without the spleen destroying the red cells so fast, the Hb can be maintained at a higher level, without transfusion. However, this is not effective on all intermedias and can also have just a short term effect, so eventually, the patients does have to resume transfusions.
Miltswifey should have had more transfusions as a child to prevent the bony changes in her skull. Is she a major or intermedia? The question alone shows how vague the intermedia classification is. My guess is that some doctors would've put her on much more regular transfusions and kept her Hb over 10. This would've required much more frequent transfusions which may have placed her in the major classification.
One thing this demonstrates is that it is extremely important to have thal care comprehensive and properly managed. The decision to begin regular transfusions should be made at the first sign of abnormal bone development. Ability to maintain a certain Hb level is important but how well the patient maintains physically should be an equal factor in transfusion decisions.