To evaluate the viral production of these two cultured cell lines, Western blotting-based immunoreactivity of gp120 and gp41 in ACH-2 cells stimulated by PMA was observed, but no immunoreactivity was detected in A3.01 cells was evident, demonstrating the status of latent infection in ACH-2 cells (Additional file 1: Figure S1). The gene discussed is ITIH4; the disease is disease arising from reactivation of latent virus.