Cryptococcosis is an important complication of solid-
organ transplantation, but the risk factors for disease are poorly understood. The goal of this study was to investigate whether specific or nonspecific serum
immunoglobulin levels determined in samples obtained before and after solid-
organ transplantation differed in patients who did or did not develop
cryptococcosis after
transplantation. We analyzed pretransplantation sera from 25 subjects, 15 who subsequently developed
cryptococcosis and 10 who did not, and posttransplantation sera from 24 subjects, 13 who developed
cryptococcosis and 11 who did not. All subjects received a
tacrolimus-based immunosuppressive regimen. Total
immunoglobulin levels were measured by immunodiffusion, and Cryptococcus neoformans capsular
polysaccharide glucuronoxylomannan (GXM)-specific serum antibody levels were determined by
enzyme-linked
immunosorbent assays. The results showed that solid-
organ transplantation had a significant effect on total
immunoglobulin and GXM-reactive antibody levels. GXM-reactive antibody levels differed in subjects who did and did not develop
cryptococcosis. In pretransplant serum samples, the levels of GXM-reactive
immunoglobulin M (
IgM) were significantly lower in subjects who developed
cryptococcosis after
transplantation than in those who did not. For posttransplant serum samples, the levels of GXM-reactive
IgM and
IgG were significantly higher among the subjects who developed
cryptococcosis than among those who did not. These findings suggest that perturbations in the preexisting antibody or B-cell repertoire and/or related to treatment of rejection, transplantation, or immunosuppressive therapy could translate into an increased risk for transplant-associated
cryptococcosis.