Recombinant interleukin-2 infusions and decreased IgG2 subclass
concentrations [see comments]
RJ Soiffer, C Murray, J Ritz, N Phillips, D Jacobsohn, S Chartier and DM Ambrosino
Division of Hematologic Malignancies, Dana-Farber Cancer Institute, Harvard
Medical School, Boston, MA 02115.
The administration of low doses of recombinant interleukin-2 (rIL-2) in
vivo to patients with malignant neoplasms has been demonstrated to
selectively increase the number of circulating natural killer (NK) cells in
these patients. Recent evidence from SCID mouse models suggests that IgG
subclass levels can be influenced by the presence and activity of NK cells.
Therefore, we sought to examine the effect of rIL- 2 infusions on human
serum IgG subclass concentrations. We determined serum IgG subclass
concentrations in 27 cancer patients receiving low- dose rIL-2 by daily
continuous intravenous infusion. Eleven of these patients had active,
metastatic, nonhematologic tumors; 16 patients had received IL-2 when they
were in a minimal residual disease state after autologous or allogeneic
bone marrow transplantation. Samples obtained before beginning IL-2 therapy
and 8 to 10 weeks into therapy were tested. Treatment with IL-2 resulted in
an increase in the percentage of CD56+ NK cells from 18% to 54% (P =
.0001). A significant decrease in geometric mean IgG2 concentration from
2,017 micrograms/mL to 1,655 micrograms/mL was noted over this time
interval (P = .03). Furthermore, the geometric mean IgG2 concentration
after treatment was significantly lower than that of healthy controls (P =
.026). In contrast, no significant changes in serum IgG1, IgG3, or IgG4
were noted during r- IL2 infusions. Our data suggest that rIL-2 treatment
selectively decreases serum IgG2 concentrations. We speculate that
increased NK cells mediate downregulation of human serum IgG2.
Volume 85,
Issue 4,
pp. 925-928,
02/15/1995
Copyright © 1995 by The American Society of Hematology
