The role of soluble immune response suppressor lymphokine in the prediction of steroid responsiveness in idiopathic nephrotic syndrome.

The role of serum soluble immune response suppressor (SIRS) lymphokine in the prediction of steroid responsiveness in idiopathic nephrotic syndrome was investigated. Serum SIRS was detected by its capacity to suppress the induction of plaque forming cells in pokeweed mitogen-stimulated in vitro lymphocyte culture in a dose dependent manner, and specificity was determined by the ability of monoclonal anti-SIRS coated beads to specifically absorb the suppressor activity. Serum SIRS was present in 7 of 18 patients with steroid responsive nephrotic syndrome and in 1 of 6 patients with nephrotic syndrome who were resistant to steroid treatment. It was also found in 2 of 4 patients with nephrotic syndrome which would be expected to be resistant to steroid treatment, in 2 of 10 patients with steroid responsive nephrotic syndrome in remission and in 2 of 8 normal healthy controls but was absent in 8 patients with non-nephrotic proteinuria secondary to a variety of renal disease. It was concluded that, although serum SIRS was present more often in patients with steroid responsive nephrotic syndrome, it is not a sensitive enough assay for predicting the response to treatment.