Correction

Vol. 203, No. 6, June 12, 2006. 1386.

Please note that an error appeared in the online early release html version of this story. The final html, pdf, and print versions have been corrected. For reference, the correction appears below.

An error appears in the last sentence of the 6th paragraph. The sentence should read “A decrease in ICOS expression has also been reported on T cells from patients with XLP.”