Infections generally occur in a predictable fashion that is highly correlated with the sequential changes in host immune defenses (Fig 4).
In the preengraftment period, at the time of profound neutropenia and damaged mucosal membranes, bacterial and fungal infections are the leading cause of morbidity and mortality. Fungal infections are rarely the cause of fever during the first week of neutropenia but, as neutropenia continues, Candida species followed by Aspergillus species are prominent pathogens. Although C albicans remains the most common isolate, other species are increasingly reported in patients receiving fluconazole prophylaxis.20,24
The postengraftment period is the time when localized manifestations of hematogeneously spread candidal infection, eg, hepatosplenic candidiasis, or chronic disseminated candidiasis, usually become apparent. At this point, the neutrophil response has recovered sufficiently to engender an inflammatory response. The second peak of Aspergillus infection occurs among allogeneic HSCT recipients in this period.10 Throughout the late postengraftment period, after day 100, IFI is rare, except in patients with chronic GVHD or in those having a relapse of underlying malignancy.
Two epidemiologic studies documented the time course of Candida and Aspergillus infections (Fig 5). Day 28 was the median time for development of candidemia in 30 patients after allogeneic HSCT.20 In contrast, the time to invasive Aspergillus infections in 144 patients after transplant (91% allogeneic, 9% autologous donors) appeared bimodal,10 with a large second risk period corresponding to GVHD in allograft recipients.
Course Number: V035D
This CME Expires on July 1, 2005; no tests will be accepted after this date.
This course is accredited by
The University of Pittsburgh School of Medicine, Center for Continuing Education
and The International Immunocompromised Host Society