<qa>  What is the goal of the study?This study has several goals. One aim is to look at types of autism that are known, such as the regressive subtype, where skills are lost. We will explore whether there is a unique change in immune functioning related to this subtype. Another aim is to serve as one of the sites that will pilot a larger natural history study, entitled Autism Phenome Project. The goal is to further understand autism by identifying other subtypes. 