Increased Frequencies of the CD29 and CD57 Markers and Decreased Frequency of CD45RA Within CD4+ and CD8+ Subsets after Allogeneic Bone Marrow Transplantation in Man

Two monoclonal antibodies, anti-CD45RA and anti-CD29, reciprocally divide the CD4⁺ and CD8⁺ lymphocytes into CD4⁺ CD45RA⁺, CD4⁺ CD29⁺, CD8⁺ CD45RA⁺ and CD8⁺ CD29⁺ subsets. The CD4⁺ CD45RA⁺, CD4⁺ CD29⁺ and CD8⁺ CD45RA⁺ possess suppressor-inducer, helper-inducer and suppressor-effector functions respectively. Since the role of these subsets has not been established after allogeneic bone marrow transplantation we studied lymphocyte subpopulations in 12 patients 45- 227 days after the procedure. The fraction of CD4⁺ lymphocytes was significantly (P= 0.0005) decreased to 20±9% versus 43±3% in controls. Within the CD4⁺ compartment, we found an increase in the fraction of CD4⁺ cells that co-expressed CD29 (CD29⁺/CD4⁺) to 92±10% versus 48±15% (P=0.008) in controls and a concommittant decrease m CD45RA⁺/CD4⁺ to 16±12% versus 56±25% (P=0.008) Patients were also noted to have an increase in the percentage of CD8⁺ lymphocytes to 41±5% compared to 23±4% in controls (P=0.0004), Examination of the CD8⁺ subsets revealed a significant increase in the CD29⁺/CD8⁺ fraction to 97±3% versus 64±2% in controls (P= 0.008) and a decrease in the CD45RA⁺/CD8⁺ fraction to 36±11% versus 70±21% (P= 0.008). The number of cells co-expressing CD57 were also determined within the CD4⁺ and CD8⁺ subsets. In patients CD57⁺/CD4⁺ were increased to 29±7% versus 1±1% in controls (P=0.04), and CD57⁺/CD8⁺ to 49±12% versus 23±9% (P=0.02). Since CD29⁺ and CD57⁺ cells have a poor capability for IL-2 production and proliferation this shift in subset distribution may account for some of the defects in cellular immunity seen within the first year after allogeneic bone marrow transplantation.