Lymphocyte phenotype and function in chronically transfused children with sickle cell disease

Abstract

Immunologic studies were performed on mononuclear cells from ten chronically transfused children with sickle cell disease, and the results were compared with those from five other groups: 21 sickle cell patients who were not receiving regular transfusions, 6 chronically transfused children with other forms of refractory anemia, 10 previously splenectomized children, 5 boys with hemophilia A, and 27 normal adult controls. The helper:suppressor T cell ratios (T4:T8) in all groups except hemophiliacs were normal, were unrelated to the number of units transfused, and were not suggestive of findings reported for patients with the acquired immune deficiency syndrome (AIDS) or groups at risk for the syndrome. Percentages of T3, T4, and T8 cells were low in sickle cell and splenectomized patients, but not in chronically transfused patients with other anemias. Serum IgG was frequently elevated, and IgG synthesis in vitro was increased relative to IgM synthesis in sickle cell patients. Coculture experiments indicated that such findings may stem from a selective increase in IgG synthesis by B cells. Thus, transfused sickle cell patients have a particular pattern of immunologic abnormalities that is distinct from that seen in AIDS.

Are the Changes of Lymphocyte Subsets in Sickle Cell Anemia due to the Loss of Splenic Function?

“…These results are in agree ment with previous reports which demonstrated simi lar results in S C A [15,16,29] and after splenectomy [26,27,31]. Since the spleen contains approximately 50% o f B lymphocytes [31], its absence may determine a marked redistribution o f these cells among other compartments.…”

“…Conflicting data were reported for each one of these parameters in S C A [13][14][15][16][17] which could be related with the number o f previous transfusions [12]. On the other hand, there are few data for splenectomized in dividuals [16,31] and our results in general agree with these studies.…”

“…These results show that the number of lymphocytes was increased in S C A and in splenectomized subjects as have been previously reported [15,16,[24][25][26][27][28][29][30]], This increment is more pronounced in S C A and the inter pretation for this finding is unclear. Differences be tween the effect of autosplenectomy and surgical splenectomy and the influence of previous transfu sions should be considered.…”

Infections in Thalassemia and Hemoglobinopathies

“…Finally, we mention that some immune alterations similar to those mentioned for thalassemia were also found in SCD: CD4 lymphocyte reduction and CD4/CD8 ratio reduction55, 62–64; natural killer lymphocyte reduced activity64; high serum immunoglobulin65, and elevated B lymphocytes55. On the other hand, the published data are less uniform and there are also some studies reporting the normality of these immunological features66,67.…”

Leukocytes in Transfusion Medicine — An Overview of Functions and Clinical Implications

“…Furthermore following multiple transfusion an increase in B-cellimmunoglobulin production in vitro may be seen which goes along with an elevation of serum immunoglobulin levels [78,79]. In thalassemia patients a transfusion-related increase in CIg-positive cells was demonstrated [80].…”