Natural killer cell activity in infants and children excreting cytomegalovirus.

Abstract

Natural killer cell (NKC) activity against uninfected and cytomegalovirus (CMV)-infected fibroblasts and K562 cells was assessed in 39 infants and children excreting CMV and 89 controls. NKC activity in cord blood specimens, healthy donors up to six months old, and donors older than six months showed significant increases (P less than .02) with age. NKC activities of CMV excreters correlated with acute disease characterized by interstitial pneumonitis (IP) and showed differential responses to the three target cells. CMV excreters younger than six months with IP showed greater mean percentage lysis (MPL; 36.6% +/- 10.5%) of CMV-infected cells than did those without pneumonitis (25.9% +/- 10%) or controls (22.1% +/- 8.0%). Excreters older than six months with IP showed activities comparable to controls; NKC activities of excreters without IP were depressed. Significantly elevated activity against uninfected fibroblasts characterized patients with IP regardless of age (MPL, 30.2% +/- 7.3% vs. 4.2% +/- 2.0% for healthy controls and 6.3% +/- 5.4% for excreters without IP). Increased cytolysis of uninfected fibroblasts was therefore associated with more active disease.