RESUMO
There is a strong evidence of endothelial cell activation in beta thalassemia and vascular complications in these patients are more frequent. The objective of this work is to study the levels of circulating soluble vascular cell adhesion molecule [sVCAM-1] and Von Will brand factor [vWF] as parameters of endothelial cell activation in a group of children with P-thalassemia major, and their relation to duration of the disease. The study was conducted on 35 patients with P-thalassemia major, recruited from the hematology outpatient clinic of Alexandria University Children's Hospital, who were divided into two groups. Group I included 15 young children with a disease duration 55 years and group I1 included 20 older children and adolescents with disease duration > 5 years. Ten apparently healthy children of matching age and sex served as control group. Children were subjected to full clinical examination with special emphasis on signs of vascular affection. Serum levels of: sVCAM-1 were measured by enzyme- linked immunosorbent assay [ELISA], and vWF by radial immunodiffusion. The results showed that 4 of the studied patients had pulmonary hypertension and one patient suffered from left lower limb deep vein thrombosis. Soluble vascular cell adhesion molecule-1 results demonstrated significantly higher levels in both thalassemic groups in comparison with controls and non-significant difference between the two groups themselves. A positive correlation was found between sVCAM-1 levels and serum ferritin in both groups, and with vWF in-group II only [P=0.007, 0.042 and 0.031 respectively]. There was a non-significant difference between the levels of vWF in both thalassemic groups and controls [k0.093]. There was no statistically significant difference as regards sVCAM-1 and vWF levels in non-splenectomized and splenectomized children in both groups [P=0.545, P=0.219]
Conclusion: measurement of sVCAM-1 might be a useful marker for the follow up of vascular disease in transfusion dependent thalassemic patients
RESUMO
The increased number and long term survival of immunocompromised children with acute lymphoblastic leukemia [ALL] might lead to their affection with fatal varicella, The objective of this study was to investigate the safety and immunogenicity of varicella vaccine in a group of children with ALL and non-immune siblings of leukemic children. Forty-five children with ALL and 26 healthy siblings of children with ALL all with negative history of chicken pox were immunized with live attenuated varicella vaccine [Oka strain]. At the time of the study, thirty-five were still receiving maintenance chemotherapy [group I] and 10 have completed their maintenance therapy [group II]. Group III included the 26 healthy siblings of children with ALL. The control group comprised 15 children with ALL who acquired natural varicella virus infection [group IV]. Serum IgG antibodies against varicella zoster virus [VZV] were measured by ELISA at baseline and at 3 and 6 months after vaccination for leukemic children and at baseline and 6 weeks after vaccination in healthy siblings, and once for the control group. The results showed that patients in groups II and III tolerated well the vaccine with no side effects. However, varicella form rash occurred in 5 [14%] children out of 35 cases of group I, Three of them were treated with oral acyclovir. Zoster occurred in 3 cases [8.5%] of group I. Seroconversion in 71.1% of children of group I and 70% of group II after one dose and in 91.4% of group I and 80% of group II after a second dose of the vaccine. The mean serum level of [VZV] IgG was significantly higher in groups III and IV than groups II and I after one dose of the vaccine [F=24.765, P<0.001]. The mean serum level of [VZV] IgG was significantly lower in ALL in children of group I after 6 months of vaccination compared to the healthy siblings [P<0.001]. However, during 3 years follow up; breakthrough varicella occurred in only one case of group II after household exposure. It was mild with no fever and with only 7 skin lesions
Conclusion: varicella vaccine administered carefully with close follow-up is safe and beneficial to leukemic children. The vaccine-induced immunity appeared effective in preventing or modifying chicken pox after exposure to natural disease in ALL children