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: Discriminating between primary SLE - induced affection of the musculoskeletal system and drug - induced side effects is important for appropriate treatment of SLE patients .
### Output Text:
Discriminating between primary SLE - induced affection of the musculoskeletal system and drug - induced side effects is important for appropriate treatment of SLE patients . 