Brief report

Lack of association between sCTLA-4 levels in human plasma and common CTLA-4 polymorphisms

Andrew Berry, Matt Tector and Martin K Oaks^*

• * Corresponding author: Martin K Oaks martin.oaks@aurora.org

Author Affiliations

Transplant Research Laboratory, Aurora St. Luke's Medical Center, 2900 W. Oklahoma Ave., Milwaukee, WI, 53215, USA

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Journal of Negative Results in BioMedicine 2008, 7:8 doi:10.1186/1477-5751-7-8

Published: 12 November 2008

Abstract

Background

Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an important downregulatory molecule expressed on both T and B lymphocytes. Numerous population genetics studies have documented significant associations between autoimmune diseases and single nucleotide polymorphisms (SNPs) within and around the CTLA-4 region of chromosome 2 in man. Furthermore, circulating levels of a soluble form of CTLA-4 (sCTLA-4) have been reported in a variety of autoimmune mediated diseases. Despite these findings, the relationship between levels of sCTLA-4 protein, mRNA transcript levels, and SNPs within the CTLA-4 region have not been clearly defined. In order to further clarify this relationship, we have tested four different SNPs within the CTLA-4 region among subjects whom are negative (n = 53) versus positive (n = 28) for sCTLA-4.

Results

Our data do not support a clear association between sCTLA-4 levels and any of the four SNPs tested.

Conclusion

The variation in the SNPs tested does not appear to effect sCTLA-4 protein levels, despite reports that they affect sCTLA-4 mRNA.