Circulating gamma delta-T-cell-receptor-positive lymphocytes in sarcoidosis

We investigated phenotypic surface markers of peripheral blood lymphocytes including expression of gamma delta T cell receptor (TCR gamma delta) in 185 patients with sarcoidosis and 42 normal subjects. The proportion of TCR gamma delta+ lymphocytes in peripheral blood of patients with sarcoidosis (5.5 +/- 5.4%) was significantly higher than in normal subjects (3.6 +/- 2.2%; p < 0.05). A number of patients with sarcoidosis had prominently increased levels of circulating TCR gamma delta+ lymphocytes. Successive measurements of circulating TCR gamma delta+ lymphocytes demonstrated the persistence of increased levels of circulating TCR gamma delta+ lymphocytes. We divided the patients with sarcoidosis into two groups, one with high, the other with low TCR gamma delta+ expression. Compared with the low-value group, the high-value group had significantly decreased levels of circulating CD4+ lymphocytes, decreased incidence of a positive tuberculin reaction, and higher levels of serum angiotensin-converting enzyme and lysozyme, suggesting that these two groups may differ in their immunological response and disease activity of sarcoidosis. Measurement of TCR gamma delta+ expression in the circulation seems to be useful for estimating the disease activity of sarcoidosis.