In AD patients the percentage of helper/inducer CD3+CD4+ subpopulation of peripheral blood lymphocytes (31.7 ± 5.2) was lower as compared to that of controls (43.7 ± 5.1, p < 0.001), whereas the percentage of CD3+CD8+ cytotoxic/suppressor lymphocytes (30.6 ± 10.3) did not differ as compared to controls (26.5 ± 4.9, p > 0.05) (Table 1). The gene discussed is CD4; the disease is Alzheimer disease.