EXHIBIT 16 TO FORM 8-K/A February 24, 2003 Securities and Exchange Commission 450 Fifth Street, N.W. Washington, DC 20549 Gentlemen: We have read Item 4 of Form 8-K/A dated February 11, 2003, of Amerimmune Pharmaceuticals, Inc. and are in agreement with the statements contained in the second and fifth and sixth paragraphs on page 2 therein. We have no basis to agree or disagree with other statements of the registrant contained therein. /s/ Ernst & Young LLP