1. ¹Department of Clinical Immunology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
2. ²Center for Allogeneic Stem Cell Transplantation, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
3. ³Department of Hematology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden

Correspondence: Dr A-C Norlin, Clinical Immunology, F 79, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm SE-141 86, Sweden. E-mail: anna-carin.norlin@karolinska.se

Received 26 January 2007; Revised 31 August 2007; Accepted 7 September 2007; Published online 12 November 2007.

Abstract

The aim of this study was to evaluate the effects and kinetics of IgG levels after allogeneic stem cell transplantation (SCT). This study retrospectively examines 179 consecutive patients undergoing SCT between 1995 and 2002. Diagnoses included acute and chronic leukemia (n=136), solid tumors (n=11), other malignancies (n=16) and non-malignant diseases (n=16). Standard myeloablative conditioning was given to 146 patients, and 33 patients received reduced intensity conditioning. Serum samples for measurement of IgG levels were collected 3, 6 and 12 months after SCT, and then yearly. IgG levels increased after SCT throughout the study period. Factors that were associated with low IgG levels after SCT were acute graft-versus-host disease (GVHD), patient age 30 years, female donor-to-male recipient, not receiving anti-thymocyte globulin and type of GVHD prophylaxis. Compared to patients with moderately low or normal levels as measured twice during the first year after transplantation, patients with low IgG levels (<4 g/l) showed a decreased survival rate (54 vs 71%, P=0.04) and an increased incidence of transplant-related mortality (27 vs 9%, P<0.01). IgG levels generally increase after SCT. Persistent low levels of IgG are a risk factor for death after SCT.