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: We conclude that the CYA cardiotoxicity correlates with CYA dosage as calculated by body surface area , and that patients with aplastic anemia and immunodeficiencies can be effectively prepared for bone marrow grafting at a CYA dose of 1 . 55 g / m2 / d for four days with a lower incidence of cardiotoxicity than patients whose CYA dosage is calculated based on weight .
### Output Text:
We conclude that the <span class="chemical">CYA</span> cardiotoxicity correlates with <span class="chemical">CYA</span> dosage as calculated by body surface area , and that patients with aplastic anemia and immunodeficiencies can be effectively prepared for bone marrow grafting at a <span class="chemical">CYA</span> dose of 1 . 55 g / m2 / d for four days with a lower incidence of cardiotoxicity than patients whose <span class="chemical">CYA</span> dosage is calculated based on weight . 