Effects of immunoglobulin G and low-dose amphotericin B on Candida albicans infections in burned mice

Abstract

Candidiasis causes serious problems for compromised hosts. Effective treatments for Candida albicans infections are few. To see if immunoglobulin (Ig) therapy could be beneficial, burn-immunocompromised mice were treated intravenously with 2.5 mg of five different IgG preparations 48 h postburn and post-C. albicans challenge. Despite up to fourfold differences in titer (1:1,600 to 1:6,400) to C. albicans, all preparations improved 10-day survival about 30% (P less than 0.0001). Treatment with a low dose of amphotericin B (AmB; 0.09 mg/kg of body weight) intravenously 24 and 48 h after burn and challenge improved survival 9 to 45% (P less than 0.0001). Treatment with a low dose of AmB plus IgG showed the same results as treatment with AmB alone and better results than treatment with IgG alone. Quantitative renal cultures from burned mice treated with AmB plus one IgG preparation, Sandoglobulin, showed that C. albicans counts decreased in sham-treated mice from 7.21 +/- 0.15 log10 CFU/g (mean +/- standard error of the mean) to 5.31 +/- 0.34, which was significantly less than counts with AmB (6.11 +/- 0.35) or Sandoglobulin (6.39 +/- 0.18) treatment alone. We conclude that (i) by using decreases in mortality and in renal fungal load as end points, treatment with IgG preparations alone or with a low dose of AmB alone protected burn-immunocompromised mice from candidiasis; (ii) though AmB plus one IgG preparation significantly decreased renal fungal load, the combination did not significantly decrease mortality beyond that found with AmB alone; and (iii) survival data did not correlate with IgG titers to C. albicans.