Measurement of specific enzyme activities associated with diseases in leukocytes of lysosomal storage diseases

Lysosomal Storage Diseases (LSD) are a group of metabolic disorders that contain almost more than 40 inherited disorders and its approximate incidence in births is 1/40.000-1/100.000.000.Lysosomal storage diseases result defects in lysosomal functions because of mutations on genes that code lysosomal enzymes. If one of these enzymes is defective, the large molecules accumulate within the cell. Storeged molecules cause cell disfunction and death.These are usually mukopolisakkarid (MPS), sfingolipid, mucolipid, glycoprotein, oligosaccharide and glycogen. Measuring the enzyme activity in leukocyte or dried blood sample,is the most common and principal method.However, sometimes it can be wrong positive or wrong negative results in dried blood samples. So enzyme activity in leukocyte is offered for certain diagnosis. But in case of manuel leukocyte izolation, results are changeable for especially heterozygote patients. İn this study, patients's and healty people's T lymphocyte, B lymphocyte,monocyte- macrophage are izolated, using CD8, CD14, CD19, CD33 receptors, by flow cytometry and measured enzyme activities. Comparison of levels of each leukocyte cell surface antigen between GD patients and healthy controls were expressed as % percentage. Our results show that in GD patients CD33, CD14 and CD8 leukocyte cell surface antigens were insignificantly higher compared to controls. Only the percentage of CD19+ leukocytes in GD patients were significantly higher compared to the control group (p<0.05). There was statistically significant difference in glucocerebrosidase activities of leucocytes (positive for CD33, CD19, CD14 and CD8) between Gaucher patients and healthy controls(p≤0.001). We also investigated the genetic properties of GD patients. Homozygote GD and Heterozygote GD are compared each other and with control groups. CD33+ percent of Homozygote GD are significanly higher than the heterozygote patients (p≤0.038). Treatment duration and L1-L4 scores of Homozygote GD patients are significantly lower than those of heterozygote GD patients (p≤0.029, p≤0.016). There are no significant differences in terms of other biochemical parametres. When comparisonsa were made regarding to hepatomegaly, Z score of GD patients without hepatomegaly, is significantly higher than the patients having hepatomegaly (p≤0.009). There are no significant differences in terms of other biochemical parametres. This study indicates that the increase in CD 19+ leukocytes may serve as a useful marker to predict the leokocyte infiltration in GD patients. Since experimental anti-CD19 drugs are in development for direct treatment specifically towards B-cell cancers, close monitorization of the CD19+ leukocyte levels may also serve as a marker to show the response to treatment. Key Worlds: Gaucher; CD19; CD33