In particular, NA sequencing analysis of pandemic influenza virus was achieved for 13 treated patients (8/13 with shedding duration > 6 days, of whom 3 were immunocompromised, 2 with HIV and 1 with leukaemia; 12 with oseltamivir alone, 1 sequentially treated with oseltamivir and zanamivir). The gene discussed is XK; the disease is leukemia.