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: Of the cyclosporine patients , 15 % had symptoms related to CMV infection .
### Output Text:
Of the <span class="chemical">cyclosporine</span> patients , 15 % had symptoms related to CMV infection . 