In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: METHODS : We analyzed the clinical and laboratory information available for all 119 patients transplanted at the Washington Hospital Center between 1999 - 2003 for whom sirolimus was a component of their immunosuppressant regimen .
### Output Text:
METHODS : We analyzed the clinical and laboratory information available for all 119 patients transplanted at the Washington Hospital Center between 1999 - 2003 for whom <span class="chemical">sirolimus</span> was a component of their immunosuppressant regimen . 