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Immunological profile after splenectomy in children with beta-thalassaemia major
K Mandalenaki-Lambrou1, E Vrachnou, C Calogeropoulou
1Department of Immunology, Athens University Saint Sophies Children Hospital, Greece.
Insights
Splenectomy in children with beta-thalassaemia major temporarily alters immune cell counts and function. Immune parameters generally recover by 30 days post-surgery, with notable changes in T lymphocyte subsets and mononuclear cells.
Area of Science:
- Immunology
- Hematology
- Pediatrics
Background:
- Beta-thalassaemia major is a severe inherited blood disorder.
- Hypersplenism is common in beta-thalassaemia major, leading to altered immune cell populations.
- Splenectomy is a potential treatment but can impact immune function.
Purpose of the Study:
- To investigate the in vitro immune functions of peripheral blood lymphocytes in children with beta-thalassaemia major and hypersplenism.
- To assess the changes in immune parameters before and after splenectomy.
Main Methods:
- Studied 12 children with beta-thalassaemia major and hypersplenism.
- Collected peripheral blood samples before and on days 2, 6, 15, and 30 after splenectomy.
- Assessed lymphocyte subsets (T3, T4, T8, B cells), T4/T8 ratio, T lymphocyte mitogenic responses (PHA), immunoglobulin levels (IgG, IgA, IgM), and monocyte phenotypes (OKM1).
Main Results:
- Pre-splenectomy: low leucocytes, normal T3/rosette, low T4, normal T8, impaired PHA response, increased B cells, normal IgG/IgA.
- Post-splenectomy (day 2): leucocytosis, decreased T cells/subsets, reduced IgM. Parameters (except IgM) recovered by day 30.
- Appearance and significant increase of large mononuclear cells (T3, T4, T8, B, OKM1 phenotypes) post-splenectomy, with an increased T4/T8 ratio but no improved T cell function.
Conclusions:
- Splenectomy causes transient but significant alterations in lymphocyte subsets and mononuclear cell populations in children with beta-thalassaemia major.
- While immune cell counts and phenotypes show recovery, functional T lymphocyte responses remain impaired post-splenectomy.
Abstract:
The in vitro immune functions of peripheral blood lymphocytes have been studied in 12 children with beta-thalassaemia major and hypersplenism. The study was performed prior to splenectomy and on the 2nd, 6th, 15th and 30th day after splenectomy. It was found that before splenectomy, patients had low numbers of blood leucocytes, normal rosette and T3 lymphocyte counts, low T4 and normal T8 lymphocyte counts with a T4/T8 ratio below 2, impaired T lymphocyte mitogenic responses induced by PHA, increased numbers of polyvalent and monovalent B lymphocytes and normal immunoglobulin levels of IgG and IgA. After splenectomy, especially on the 2nd day, leucocytosis, a significant decrease of T cells and their subsets and a reduction of the IgM levels were found. These parameters, except the IgM levels, increased until the 30th day after splenectomy and reached presplenectomy values. On the 2nd day after splenectomy, large mononuclear cells behaving like immunocytes appeared in the peripheral blood. They had the phenotype of T3, T4, T8, B lymphocytes and OKM1 monocytes. All the large mononuclear cells increased significantly on the 6th day after splenectomy and remained elevated during the whole study (30 days). The T4/T8 ratio was increased, but no increase was found in the functional responses of T lymphocytes.