In most case scenarios training while you are sick can exacerbate an already compromised immune system. It might be a bit hard to find a good study on the topic, but Web Md would suggest that if you have a temperature of 101 it might be best to wait it out.
In the case that you are getting sick one suggestion comes to mind don’t do sets to failure. However doing 10-12 sets of sub maximal singles will have limited impact on the endocrine system. I think the best bet is not raising cortisol levels any further than they currently are elevated and getting good sleep. As far as lifts go I wouldn’t do any much extra outside of a minimal warm up and minimal amounts of ancillary work. I might also suggest to increasing frequency of training if you are only training 3 times a week. It may take 2 weeks, but you will be able to hit the ground running and work to rebuild cumulative volume. Some studies do indicate that time off is beneficial so that is always an option, however age and experience seems to demonstrate too little volume and inadequate nutrition can be a deadly combination when we’re trying to at best maintain gainz.
Another way to look at it is to review previous weeks volume in relationship to tonnage. Lowering the volume to about 30-40% of what it was along with decreasing your workout time to about 30-45 minutes will likely not be too taxing and allow you to recover. Think of training sick as a deload to avoid frustration and stay the course.
http://www.mc.uky.edu/athletic_training/docs/nzsmsc-2010/Eccentric_Training_Spring2011.pdf
http://elitetrack.com/article_files/neuromuscular.pdf
http://jap.physiology.org/content/87/3/982
http://jap.physiology.org/content/85/6/2352
http://jap.physiology.org/content/85/6/2352