Functional stabilization was observed in 3/5 patients with BOS that was accompanied by a slight increase or stabilization of the number of peripheral blood CD4(+)CD25(high) cells with in vitro features of Treg cells while the other 2 non-responsive patients with BOS showed a decline in the peripheral Treg subset [72]. Here, CD4 is linked to Buschke-Ollendorff syndrome.