GSTM1 and medical procedure: No statistically significant variations were observed by comparing children at T0, T1 and T2 for the following parameters: number tonsillitis episodes between the three follow-up (ANOVA: p = 0.2), Mackenzie scores (ANOVA: p = 0.9), fever episodes (ANOVA: p = 0.2) red cell count (ANOVA: p = 1), white cell count (ANOVA: p = 1), Hb (ANOVA: p = 1), PCR value (ANOVA: p = 0.6), ESR (ANOVA: p = 0.9), ASLOT (ANOVA: p = 1), pro-calcitonin (ANOVA: p = 0.7), RT (ANOVA: p = 1).