TGFB1 and asthma: Some weaknesses in the studies involved in the controversial issue concerning the cellular source of TGFβ1 in asthma are also worthy of mention: Firstly, the Ab used in Magnan and coworkers [63], Vignola and coworkers [61], and Chu and coworkers [66] did not discriminate between the 3 isoforms of TGFβ and thus, the staining distribution and intensity is additionally confounded by TGFβ2 and TGFβ3 expression.