I don't think there isn't much difference between information systems as they are virtually the same thing. However, there is a difference between business and commerce. Business is broad and is about everything relating to business and companies, whereas commerce is a speciality of business relating specifically to the buying and selling of goods and buying and selling of companies. You can end up in the same job studying either, but business is more difficult from what I have heard as it is more broad, whereas commerce is more numbers and specific and I have heard more fun cause there is more to specialise in commerce, like HR, international business, business law, etc. However, information systems can be done in both degrees and won't have to much of a difference, it is just everything else other then information systems will be different, as explained above between the difference between business and commerce. I think for commerce information systems, technoogy is used in the specifically managing buying and selling, where as business information systems is using technology for everything relating to business. Best to ask someone studying both or either, but thats what I got from people I have asked studying commerce and/or business. Good luck!
FROM GOOGLE: Information systems is an essential element in bringing together technology, people (individuals, groups, or organisations), and data/information to effectively manage organisations. Such systems are used to analyse and facilitate strategic and operational activities in organisations.