T cells subtypes in a patient with interferon-alpha induced sarcoidosis.

A 47-year-old woman with a history of blood transfusion-acquired hepatitis C was treated with interferon-alpha when she developed fever, arthralgia, erythema nodosum, dyspnea, and diffuse alveolitis. The diagnosis of IFN-alpha-induced sarcoidosis was retained. The patient's clinical status rapidly improved after IFN-alpha discontinuation, with complete resolution of signs and symptoms. Admission and follow-up assessment of peripheral blood CD4 T cells showed a transient activation process that peaked at 1 to 3 months after onset of symptoms and discontinuation of IFN-alpha. It was marked by a mild increase in activated cells (expressing R-IL2 and HLADR), and a markedly reduced percentage of CD4 T cells expressing the costimulation molecule CD28, ie, an expansion of the CD4CD28 negative subset that is associated with proinflammatory and tissue damaging properties. This activation process also improved over time, but more slowly than clinical symptoms.