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.