Background: It has been suggested that clonal T cells may play a critical role in the pathogenesis of systemic sclerosis.
Observations: A monoclonal population of T cells was found in blood samples from 13 (34%) of 38 consecutive patients with a definite diagnosis of systemic sclerosis who were prospectively examined by T-cell receptor gamma gene rearrangement using polymerase chain reaction analysis and denaturating gradient gel electrophoresis. In the healthy control group, the same type of examination revealed a monoclonal population of T cells in the blood samples from only 3 healthy subjects (4%)(odds ratio, 12.28; 95% confidence interval, 2.76-54.64; P = .001). Patients who had a circulating clonal population of T cells were older than those who did not (67 years vs 48 years; P = .04). There was a marked relationship between systemic sclerosis subtypes and the presence of a circulating clonal population of T cells. Twelve (43%) of 28 patients with limited cutaneous sclerosis exhibited a circulating clonal population of T cells, whereas only 1 (10%) of the 10 patients with diffuse cutanous sclerosis had evidence of T-cell clonality (P<.01).
Conclusions: Clonally expanded T cells were more commonly detected in patients with limited cutaneous sclerosis than in those with diffuse cutaneous sclerosis, which is also in accordance with a possible role of clonal T cells in patients with limited cutaneous sclerosis.