Total glutathione level in patients with sickle cell disease compared with healthy controls and its association with pulmonary hypertension. Total glutathione (GSH + GSSG) levels in (A) plasma and (B) within the erythrocyte were significantly lower in patients with sickle cell disease (SCD, n = 40) compared with healthy volunteers (controls, n = 9). (C) Severity of erythrocyte glutathione deficiency was similar in patients with pulmonary hypertension (PH) when compared with those without PH (No PH)