Abstract:Objective To investigate the changes of plasma albumin (ALB) level and cellular immune function, and their relationship in elderly bed-ridden patients before and after nosocomial infection. Methods Seventy-eight elderly bed-ridden patients getting nosocomial infection during hospitalization in our department from January 2009 to December 2012 were enrolled in this study. The clinical data of the patients before getting nosocomial infection (group B, n=78), suffering from infection for ≥5d (group C, n=52) and for ≥10d (group D, n=33), and having severe sepsis/septic shock (group E, n=25) were collected and retrospectively analyzed. Another 40 elderly patients hospitalized in the same period without bed-ridden or infection served as control (group A). Plasma ALB level and cellular immune function, including peripheral blood mononuclear cell surface human leukocyte antigen-DR (HLA-DR) and T cell subsets, were compared among the patients at different periods. The group B were further assigned into group B1 (normal ALB level, n=16) and group B2 (lower ALB level, n=62) according to their ALB level. Results Plasma ALB level was significantly lower in group B than in group A (P=0.000), and significantly lower in group C, D, and E than in group A and B (P=0.000). Cellular immune function was similar in group B1 and group A. Patients of group B2 had significantly lower expression of HLA-DR, decreased absolute number of CD3+ T cells and CD4/CD8 ratio (P=0.000), significantly increased percentage of CD8+ T cells among CD3+ T cells (CD8/CD3; P=0.000), and unchanged percentage of CD4+ T cells among CD3+ T cells(CD4/CD3; P>0.05). Compared with those of group A and B, HLA-DR expression, absolute number of CD3+ T cells, CD4/CD8 ratio, and CD4/CD3 ratio were significantly lower in group C, D and E (P=0.000), and CD8/CD3 was significantly higher (P=0.000). The changes of HLA-DR, absolute number of CD3+ T cells, and CD4/CD3, CD8/CD3 and CD4/CD8 ratios were all correlated with plasma ALB level (r1=0.791, r2=0.638, r3=0.534, r4=-0.575, r5=0.580; P=0.000). Conclusion Plasma ALB level has been significantly reduced in elderly bed-ridden patients before nosocomial infection, and the level declines steadily thereafter the infection. The decreased cellular immune function before and after nosocomial infection is closely associated with the declined plasma ALB levels.