CD48 expression on leukocytes in infectious diseases: Flow cytometric analysis of surface antigen

Background: The function of CD48, one of the pan leukocyte cell surface ant igens, is not yet well understood. CD48 was recently shown to enhance the C D30-mediated activating signal to B lymphocytes. As CD48 is one of the acti vation antigens of monocytes, neutrophils and lymphocytes, a change of its expression on the cells could be expected in infectious diseases. Methods and results: Leukocytes from 27 healthy controls and 97 patients wi th various infectious diseases were stained with anti-CD38 antibody and ana lyzed by flow cytometry. On monocytes and neutrophils, the CD38 expression was increased in all of the patients with varicella, measles, rubella, infe ctious mononucleosis, streptococcus tonsillitis, sepsis and appendicitis. O n lymphocytes, a significant increase of CD38 was also detected in the pati ents with the same diseases, except those with sepsis or appendicitis. The normalization of increased CD48 expression was confirmed on monocytes at th e convalescent phase. Conclusion: These data suggest that CD48 expression on leukocytes reflects the disease activity of infectious diseases, especially of viral infections .