GSTM1 and autoimmune hemolytic anemia: The frequency of TGF-β (T/T-G/G and T/C-G/G, 80% vs. 59%, p = 0.03) and IL-10 (GCC-GCC, 16% vs. 5%, p = 0.02) high gene expression level genotypes was higher in patients with more severe anemia (Hb ≤7.5 g/dL, i.e., median of all AIHA) versus the remaining AIHA population.