Bacterial, Viral and Fungal Infections in Patients after Allogeneic Stem Cell or Bone Marrow Transplantation - A Comparison between Patients with Related and Patients with HLA-Matched Non-Related Stem Cell Donors.

Bacterial, viral and fungal pathogens frequently cause severe, life-threatening infections in immunocompromised patients after allogeneic stem cell transplantation (SCT). We investigated whether patients with related stem cell donors (group A) developed infections less frequently than patients with HLA-matched, non-related donors (group B). Fifty-nine consecutive patients treated at our transplantation unit between April 2004 and January 2005 were included into the analysis. We documented demographic and clinical characteristics at baseline, treatment, clinical course, microbiological examinations, clinical and radiological signs of infection and mortality. Of the total 59 patients analyzed, 22 received stem cells from related and 37 from HLA-matched non-related donors. Both groups were well balanced regarding age and weight. 50% of the patients in group A and 60% in group B were male. Most frequent diagnoses were acute myeloid leukemia (30 of 59 patients [50.8%]; group A: 68.2%; group B: 40.5%), multiple myeloma (15.2%), acute lymphoblastic leukemia (11.9%) and chronic myeloid leukemia (10.2%). Bone marrow was more often the stem cell source in group A (45.5%/ 10 patients) than in group B (10.8%/ 4 patients), peripheral stem cell transplantation respectively was predominant in the unrelated group (86.5%/ 32 patients) versus the family donor group (54.5%/ 12 patients), cord blood was used as unrelated stem cell source in1 patient (2.7%). Clinically documented infections occurred in 6% in group A and in 14% in group B. Pulmonary infiltrates were observed more frequently in group A (11 patients/ 50%) than in group B (16 patients/ 43.2%). The predominant findings were atypical infiltrates (total 16 patients), followed by signs of fungal (total 7 patients) and bacterial pulmonary infiltration (total 4 patients). Microbiologically documented infections were detected in all patients. The average number of pathogens was equal in both groups. Detected pathogens were HHV-6 (48 patients), coagulase-negative Staphylocci (17 patients), EBV (14 patients) and CMV (11 patients). Three fungal infections were detected by microbiological approaches in group A (2 × Candida albicans, 1 × Pitysporum ovale) compared to nine fungal infections in group B (5 × Candida albicans, 1 × Candida glabrata, 1 × Candida parapsilosis, 2 × Geotrichum capitatum). Two years after transplantation, 55.9% of patients were alive (group A: 68.2%; group B: 48.6%). Patients with AML had a two-year survival of 50% (group A: 53.3%; group B: 46.7%). In our study, we observed no clear relation between frequency of infection and donor type, yet there was a trend towards more invasive fungal infections in the unrelated group (13% group A vs. 24% group B).