Autoimmune cross-targeting hypothesis: a virus marks the inside of a cell while a larger infection marks the outside and the combination triggers autoimmune disease. The immune system is instructed to destroy both the inside and the outside of the target.
http://en.wikipedia.org/wiki/Drug-induced_lupus_erythematosus
http://en.wikipedia.org/wiki/Anti-smooth_muscle_antibody
Hydralazine is a smooth muscle relaxant and goes inside of muscles (so instead of a virus marking the inside of the muscle it is hydralazine)
http://en.wikipedia.org/wiki/Hydralazine
Monocycline which is an antibiotic for acne appear to also get inside of muscles hence the muscle cramps of the patients taking the drug again replacing the virus for marking the inside
Drug induced Hemolytic anemia has the reverse scenario where the drug is marking the outside of the red blood cells
http://en.wikipedia.org/wiki/Autoimmune_hemolytic_anemia
Red blood cells become coated with penicillin
http://asheducationbook.hematologylibrary.org/content/2009/1/73.full
The virus in this case is hepatitis C (or any other virus that can infect red blood cells...they can try but red blood cells have no nucleus or mitochondria to replicate in)
http://www.ncbi.nlm.nih.gov/pubmed/11799634
Another option would be a bone marrow virus like RSV
http://www.atsjournals.org/doi/full/10.1165/rcmb.2010-0121OC#.VT8EySFViko
a virus changing what is on the inside before it becomes a Red blood cell
RSV and anemia associations
http://www.sciencedirect.com/science/article/pii/S1201971213000544