Phenotypes of peripheral blood lymphocytes during acute hepatitis A.

ABSTRACT. We investigated peripheral blood lymphocyte phenotypes of 74 patients at weekly intervals during the course of acute hepatitis A. In the second week after onset of jaundice, a significant elevation of total lymphocytes was observed (4096 × 106± 1003 × 106/l vs. controls 3038 × 106± 1208 × 106/l, p < 0.005). However, no change in the relative percentages of B-cells (CD20+), T-cells (CD3+ or CD2+), or T-cell subpopulations (CD4+ helper cells and CD8+ suppressor cells) could be demonstrated during the course of the disease. Activated T-cells (CD3+DR+) were elevated during the first week (204 × 106± 134 × 106/l vs. normal 91 × 106± 54 × 106/l, p<0.005) and during the second week (202 × 106± 82 × 106/l, p < 0.0005) after onset of disease and returned to normal values until the third week. Cells expressing phenotypes of lymphocytes capable of exerting non-MHC-restricted cellular cytotoxicity, i.e. Natural Killer cell activity (CD57+, CD16+, and CD56+) were significantly elevated in percentage in the first week of disease, as compared to controls (CD57: 14.5 ± 7.0% vs. 9.3 ± 5.8%, p <0.05; CD16: 13.4 ± 7.3 vs. 9.5 ± 5.1%, p < 0.05; CD56: 10.5 ± 3.5% vs. 8.0 ± 1.5%, p < 0.005). Also the absolute numbers of these lymphocyte subpopulations were found to be elevated during the first and second week. The increase in NK cells in the initial phase of acute hepatitis A suggests an important role of these cells in the first line of defence in this disease.