Plasma proteins and lymphocyte phenotypes in long-term plasma donors

The possible effects of long-term plasma donation remain unknown, but it is important to investigate them so that donor safety is ensured. The purpose of this study was to determine if long-term plasma donation alters plasma proteins or lymphocyte phenotypes.

Two groups of long-term plasma donors, source plasma donors (n = 20) and Rh immune globulin plasma donors (n = 26), were compared with whole blood donors (n = 29) and nondonor controls (n = 30). Blood samples were obtained prior to donation. Serum protein, albumin, globulin, and immunoglobulin levels were determined. In an assay using whole blood, lymphocyte phenotypes were characterized with a panel of single- and dual-labeled monoclonal antibodies and subsequent analysis by flow cytometry.

As compared to the nondonor controls and/or whole blood donors, the mean values for serum protein, globulin, and IgG levels were lower in both plasma donor groups, with a significant negative correlation between donation frequency and serum protein values for the source plasma donors. Albumin levels were within normal ranges for both groups of plasma donors. No significant differences existed among the donor groups in total white cell counts, the percentage or absolute number of lymphocytes, T (CD3) cells, or helper T (CD4) cells. However, there were increased percentages of B (CD19) cells and decreased percentages of suppressor T (CD8+/CD11b+) cells and natural killer cells in both groups of plasma donors as compared to nondonor controls.

Many plasma donors have low levels of serum protein, globulin, and IgG. In addition, they have increased percentages of B cells and decreased percentages of suppressor T and natural killer cells. The clinical significance of these findings warrants further investigation.