An investigation of immunological subclass function in burned adults

The serum concentrations of the immunoglobulin subclasses and their functional activity against pneumococcal polysaccharide (PPS) and E. coli antigens have been studied for 15 days in 12 adult burned patients, of whom six were randomly allocated to receive biosynthetic human growth hormone (somatropin) and six to form a control group. The concentrations of the major subclasses, IgG1 and IgG2, fell below their normal ranges as a result of injury by burning but had recovered significantly by the eleventh day of the study. There were no significant changes in the concentrations of the IgG3 and IgG4 subclasses, however, the relative proportions of the four subclasses remained unchanged and were comparable to those found in normal man. Significantly reduced functional activities, compared with normal volunteers, were observed in all the subclasses except IgG1. The activities of the major subclasses during the study were correlated with their serum concentrations and when corrected for their concentrations were comparable to those of normal blood donors. There were no significant increases in concentrations or activity of the subclasses as a result of somatropin administration. It is concluded that patients with moderately sized burns have reduced immunoglobulin function which results from the changes in serum concentration rather than from any qualitative change and that somatropin administration results in no improvement in immunoglobulin function.