Does bioluminescence occur in humans too?
From the article you linked:


  virtually all living organisms emit extremely weak light, spontaneously without external photoexcitation. This biophoton emission is categorized in different phenomena of light emission from bioluminescence, and is believed to be a by-product of biochemical reactions in which excited molecules are produced from bioenergetic processes that involves active oxygen species


They reference these two works. The first is a 1988 review from Popp et al. (1988):

Biophoton emission - Experientia 44:543–600. (sorry, I cannot find the link to a full text...)

Fritz-Albert Popp is the biophysicist who first developed the biophoton theory.

The second work they reference is by the same first author:

In vivo imaging of spontaneous ultraweak photon emission from a rat's brain correlated with cerebral energy metabolism and oxidative stress. - Kobayashi M, et al.

Finally, a search in Pubmed reveals various other articles by different authors studying different species.