And at study conclusion, the investigators will again judge their disease severity and check their vitamin D levels in addition to tests of cathelicidin levels. The investigators believe that at study conclusion, the investigators will have achieved several important objectives. First, as a public health benefit, the investigators will show that large doses of supplemental vitamin D are safe in children and provide more benefit with less risk. Our patients will achieve those levels of vitamin D agreed by expert opinion that are required to cause effects on the immune system, and the investigators will see an increase in the amount of cathelicidin produced by their immune cells. As an added piece of information, the investigators would like to determine if there are any improvements in disease activity in patients supplemented with vitamin D.