bone marrow is considered part of the immune system because it
Making the world better, one answer at a time. bone marrow is considered to part of the immune system because it was the key component of the lymphatic system, producing the lymphocytes that support the body's immune system.aking the world better, one answer at a time. bone marrow is considered to part of the immune system because it was the key component of the lymphatic system, producing the lymphocytes that support the body's immune system.