Background and Aim: Adenoids and tonsils are active lymphoid organs and playing an important role against invading antigens of upper aero digestive tract in children. The purpose of this study is observing the changes in cellular and humoral immunity of children six months after adenotonsillectomy.

Materials and Methods: The study population consisted of 30 children (aged 4-10 years) with chronic adenotonsillar hypertrophy and 30 age- matched healthy children. In all children serum level of IgM and IgG, percentage of T lymphocytes (CD3) , T helper (CD4) , T (CD8) and B lymphocytes (CD20) were measured. These parameters were re-measured in patients 6 months after adenotonsillectomy.

Results: Before the operation, a reduction in percentage of T lymphocytes (CD3) , TCD4, TCD8 and B CD20 was seen compared with control group. This reduction was only significant in T lymphocytes (CD3) (P.Value=0.03). The serum IgM level was not different in two groups and IgG level was elevated in two groups but not significantly different. Six months after operation the percentage of lymphocytes T CD3+, TCD8+, TCD4+ and BCD20+ was increased and reached the control group. The IgG level was also significently decreased in patients after operation (P.Value=0.00).               

Conclusion: Our results indicate that cellular and humoral immunity decreases in children with chronic adenotonsillar hypertrophy preoperatively and increases to healthy children level, six months postoperatively. It means that chronic adenotosillar hypertrophy affects some parameters of cellular and humoral immunity and adenotonsillectomy by removing chronic stimulations reverses these changes without any negative effect on immune function of patients.