BAX and bacterial infectious disease: We next monitored intestinal stem cell proliferation in the midgut of flies expressing upd3 RNAi in haemocytes, or of flies lacking nearly all haemocytes due to the expression of pro-apoptotic genes Bax (see above) or hid. Neither the absence of plasmatocytes, nor the silencing of upd3 in haemocytes affected the gut mitotic index in response to oral bacterial infection (Figs 7D, 7E and S6B).