According to the univariate analysis (Table 2), the factors associated with more frequent infections were poor performance status (ECOG> 2, P = 0.038), advanced stage (Durie-Salmon stage III, P = 0.011; ISS stage III, P = 0.005), more severe anaemia (Hb < 90 g/L, P = 0.014) and elevated CRP (> 10 mg/L, P = 0.007). The gene discussed is GSTM1; the disease is anemia.