Depression of cellular immunity after multiple trauma in the absence of sepsis

We have previously reported that severe burn injury was regularly accompanied by impaired lymphocyte responses to T cell mitogens, circulating suppressor lymphocytes, and serum factors suppressive of lymphocyte activation. However, in burned patients it was difficult to determine whether these manifestations of suppressed immunity were predictive of, or the result of, sepsis which was ubiquitous in this population. In an attempt to clarify this issue, we have studied 31 patients with multiple trauma (without burns) mean age, 31 years; average injury severity score, 22; range, 9-56; in whom sepsis was less common. Patients were tested for lymphocyte response to the T cell mitogens PHA and Con A, the percentage of circulating putative suppressor (OKT8) and helper (OKT4) T cells using monoclonal antibodies, circulating suppressor cell activity as revealed by functional assays, and serum suppression of lymphocyte activation. Patients were compared with ten normal volunteers (mean age, 32) studied simultaneously. Significant suppression (greater than 50% compared with controls) in lymphocyte responses to mitogens 1 to 5 days after injury was seen in 12 patients, was accompanied by a shift in the ratio of helper (OKT4) to suppressor (OKT8) T cells (patients, 0.96:1; normals, 1.82:1; p less than 0.01), and was followed by the appearance of significant (greater than 50%) serum suppressive activity in six of the 12 patients. Circulating suppressor cell activity as revealed by functional assays was also seen early after injury in three of 12 patients.(ABSTRACT TRUNCATED AT 250 WORDS)