Immunorestorative properties of thymostimulin (TS) in patients with Hodgkin's disease in clinical remission

Summary Fifteen Hodgkin's disease patients (8 male, 7 female) aged 19–72 years, who had been in complete unmaintained remission for 1 year or more when the study was initiated, were given 50 mg thymostimulin (TS) IM daily for 60 consecutive days. When compared with 26–30 age- and sex-matched controls, as a group the patients' circulating E_NR⁺, OKT ₃ ⁺ , and OKT ₄ ⁺ cells were depressed (0.001P .06), whereas their OKT ₈ ⁺ cell population was not. Low (>1 SD or >2 SD below mean in controls) or borderline (mean value of two subsequent tests >1 SD below mean in controls) values of E_NR⁺, OKT ₃ ⁺ , and OKT ₄ ⁺ cells were seen in nine (group I) of the 15 patients tested, while the remaining six patients (group II) had normal T-cell proportions. Following TS treatment, the proportions of E_NR⁺, OKT ₃ ⁺ , and OKT ₄ ⁺ cells increased to normal in all group I patients. The T-cell levels, however, decreased to pretreatment values 60–70 days after completion of TS therapy. TS had no effect on the group II patients whose T-cell percentages had initially been normal. Spontaneous cell-mediated cytotoxicity (SCMC) was assessed in 11 patients, and irrespective of the baseline values, there was a significant enhancement (P<0.005) by day 15 of TS administration, which was maintained during treatment. SCMC, however, returned to pretreatment levels 60–70 days after TS was discontinued. The delayed skin test reactivity to DNCB was significantly depressed in all cases. Although TS restored the T-cell proportions, it failed to reverse DNCB reactivity from negative to positive in any of the patients tested. TS can thus restore defective T-cell frequencies and can enhance cytolytic functions that are potentially important in host immunosurveillance, but it apparently failed to improve the skin reactivity to neoantigen.