Background: Thalassemia is one of the most common genetic disorders throughout the world. Blood transfusion plays an important role in the treatment of thalassemia but it leads to numerous complications such as iron overload and alloimmunization. This study evaluated the frequency and risk factors associated with alloimmunization in thalassemia major patients living in Markazi province, Iran.
Materials and Methods: In this descriptive study, 48 thalassemia major patients who underwent blood transfusion at Amirkabir hospital were included. Patients' demographic data were recorded using a questionnaire. In order to perform alloimmunization screening and autoantibody assessment, patients were referred to Tehran Blood Transfusion Organization Laboratory.
Results: The current study was performed on 48 patients with thalassemia major,. The mean age of patients was 12.5 ± 8.3 years. Among patients 26 (54.16%) were male and 22 (45.83%) were female, 13 patients (27.08%) had alloantibodies. Among 48 patients, 19 (39.58%) had undergone splenectomy. The patients' age of the first blood transfusion ranged from 1 month to 14 months      and the mean age of the first blood transfusion was 9.5 ± 7.08 months. The blood transfusion intervals in patients were from 21 days to 40 days and the blood volume received at each transfusion session was 10-15 cc/kg of the body weight. In the current study, the data analysis indicated no significant correlation between alloantibodies and RH phenotype (P=0.43), patients' gender (P=0.9), or blood groups (P=0.4); whereas, a significant correlation was found between alloantibodies and splenectomy (P=0.02) as an increase in the prevalence of alloantibodies was reported in splenectomised patients.
Conclusion: No significant difference was found between the patients with and without alloantibodies in terms of the prevalence of Rh phenotype, gender, and blood groups. However, there was a significant difference between the patients with and without alloantibodies in terms of splenectomy.
 

Backgrounds: Epigenetic regulation such as DNA methylation plays a major role in chromatin organization Background: Chemotherapy suppresses immunoglobulin production as a result of cell toxicity. Decreased immunoglobulin levels can result in the onset of opportunistic infections. The aim of the current study is to compare the immunoglobulin G (IgG) levels of the selected vaccine-preventable disease (VPD) before and six months after chemotherapy in a group of Iranian children with malignancies.
Materials and Methods: In this interventional study, serum levels of Rubella, Diphtheria toxin, Hepatitis B virus (HBV), Tetanus Toxoid, Mumps, and Measles IgG were measured in 30 children with malignancy and previously vaccinated for these diseases. Six months after chemotherapy, serum IgG levels were reassessed and compared with their corresponding pre-chemotherapy levels.
Results: In this study, 17 (56.7%) male and 13 (43.3%) female were included. The mean age was 7.69±3.09 years. After chemotherapy, Rubella IgG levels dropped from 73.88±85.11 to 56.59±72.84 IU/mL (P<0.05; r= 0.956; 33.4% become serum negative (SN)). Diphtheria toxin IgG was diminished from 0.683±0.454 to 0.174±0.248 IU/mL (P<0.05; r=0.601; 26.7% SN). Anti-HBV IgG showed a reduction from 46.26±101.56 to 25.56±80.49 IU/mL (p<0.05; r= 0.524; 60% SN) and Anti-Tetanus Toxoid IgG fell down from 1.031±0.582 to 0.321±0.408 IU/mL (p<0.05; r= 0.365; 33.4% SN). Anti-Measles and Anti-Mumps IgGs showed no significant change (p>0.05).
Conclusion: Pediatric chemotherapy was associated with dropped serum IgG levels of most VPDs. A good correlation was also observed between serum levels of IgG before and six months after chemotherapy. Revaccination of children with malignancies may be necessary upon declined serum IgG titers.