20 healthy controls (12 male and 8 female; 18–60 yrs of age) and 41 subjects were studied: 21 sarcoidosis and 20 SSc. Sarcoidosis chest radiographs (CXRs) were staged (stage 0: normal; stage I: bilateral hilar lymphadenopathy (BHL); stage II: BHL with pulmonary infiltrates; stage III: infiltrates without BHL; stage IV: pulmonary fibrosis). Scleroderma patients were divided clinically into those with limited cutaneous systemic sclerosis (lcSSC) or diffuse cutaneous systemic sclerosis (dcSSC), those with scleroderma/polymyositis overlap and those with or without fibrosing alveolitis (FA/no FA). Antibody status is given for the scleroderma patients (ANA: antinuclear antibody; ENA: extractable nuclear antigen; ACA: anticentromere antibody; Scl 70: anti-topoisomerase antibody; Scl/PM: scleroderma polymyositis overlap antibody; Jo-1: anti-histadyl tRNA synthetase antibody). The use of immunosuppressive treatment at the time of venesection is recorded as 0 (no immunosuppressive treatment) or 1 (immunosuppressive treatment including corticosteroids up to a maximum dose of 10 mg of prednisolone or equivalent per day, but excluding powerful second line immunosuppressant agents such as azathioprine, methotrexate or cyclophosphamide). ^#: includes one patient on penicillamine.