Prevalence and reversibility of pulmonary dysfunction in refractory systemic lupus: Improvement correlates with disease remission following hematopoietic stem cell transplantation

Aim: To report the prevalence and reversibility of pulmonary function test (PFT) abnormalities among systemic lupus erythematosus (SLE) patients, refractory to therapy, undergoing hematopoietic stem cell transplantation (HSCT). Methods: Thirty-four SLE patients received 200 mg/kg cyclophosphamide and 90 mg/kg equine antithymocyte globulin followed by HSCT. PFTs were performed prior to, at 6 months, and yearly following HSCT. Results: The prevalence of significant PFT abnormalities was high (97%). Low FEV₁ and FVC occurred in 26 of 34 patients (76%). A significant abnormality in diffusion capacity of the lung for carbon monoxide (DLCO) occurred in 26 of 32 individuals able to complete DLCO testing (81%). DLCO ≤ 50% of predicted occurred in 18 of 32 patients (56%). Of these 18 patients, 4 had no thoracic diagnosis and 7 had no pulmonary diagnosis. For 3 of 11 patients with a DLCO ≤ 50% of predicted and a prior pulmonary diagnosis, the only diagnosis had been pleurisy. Ten of the 34 patients (29%) identified the lung as a target organ of the lupus and carried a pulmonary diagnosis, as indicated in Table 1. Three patients had acute alveolar hemorrhage, four patients had acute lupus pneumonitis, two patients had shrinking lung syndrome (SLS), and one patient had SLE-related pulmonary hypertension. Of these 10 patients, 4 had received prior mechanical ventilation, and 7 had required home supplemental inspired oxygen. Patients have been monitored ≤ 77 months, and 28 patients have been monitored > 18 months after HSCT. Five of 28 patients had a normal entry FVC; for each, the FVC remains normal. Of the 23 patients with an abnormal baseline FVC, 18 have improved, 15 completely and 3 partially. Eight of these 18 patients also have improved DLCO. The two patients with a diagnosis of SLS and one patient with SLE-related pulmonary hypertension improved in both parameters. Only 5 of 23 patients with an abnormal FVC did not improve. Each of these five patients retained active lupus in spite of HSCT. Conclusion: The prevalence of lung impairment among SLE patients requiring long-term immune suppression is high. Following HSCT, pulmonary impairments can improve, which is sustained if disease control is sustained.