Date of Award:


Document Type:


Degree Name:

Master of Science (MS)



Committee Chair(s)

Reed P. Warren


Reed P. Warren


Bill Barnett


Greg Podgorski


The pathogenesis of autism has proven difficult to characterize. However, in many recent studies, it is suggested that the onset of this disorder is the result of multiple etiological factors, which include genetic, immunologic, and viral elements.

Possible immunological influences found in subpopulations of patients with autism include decreased lymphocyte responsiveness, reduced natural killer cell activity, abnormal response to rubella vaccine, abnormal immune response to brain tissue, and decreased plasma levels of the fourth component of complement(C4). These aberrations and others imply a possible autoimmune mechanism in some cases for the development of autism.

C4 deficiencies have been found in subjects with established autoimmune disorders, such as systemic lupus erythematosus and chronic active hepatitis, in recent investigations. There is also evidence that the major histocompatibility genes play an intimate role in autoimmune processes. Therefore, in knowing that the C4 genes are closely linked to the major histocompatibility genes, this study determined and analyzed the human leukocyte antigen profile of autistic patients, their siblings, and parents.

In this study, it was found that the C4B complement null allele occurred in autistic patients at nearly twice the frequency compared to normals. However, the C4A complement null allele frequency was not found to be significantly altered. Several extended haplotypes were represented within the patients studied. However, the extended haplotype B44- SC30-DR4 was the only one found at a significantly increased frequency. Further investigations are needed to better understand the significance of these findings.



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