Antiphospholipid antibodies as a cause of pulmonary capillaritis and diffuse alveolar hemorrhage: a case series and literature review.
OBJECTIVE
To discuss the clinical manifestations and possible pathogenic mechanisms of the unusual syndrome of diffuse alveolar hemorrhage (DAH) and pulmonary capillaritis without thrombosis in the setting of the primary antiphospholipid antibody syndrome (PAPS).


METHODS
Four men with DAH and capillaritis in the setting of PAPS are identified. Their clinical presentations, laboratory, radiographic, and pathologic findings are reviewed as is their clinical course and response to therapy. In addition, the literature regarding DAH and pulmonary capillaritis in the setting of PAPS is reviewed.


RESULTS
The patients presented with dyspnea, hemoptysis, fever, hypoxia, and diffuse alveolar infiltrates; none had evidence of acute thromboembolic disease. All secondary causes of DAH were ruled out. All patients had positive testing for the lupus anticoagulant and high-titer anticardiolipin antibodies, including antibodies against the beta-2-glycoprotein I antigen. Three cases had lung biopsies that revealed pulmonary capillaritis and DAH with no evidence of thrombosis. All patients improved with high-dose corticosteroids. Recurrent disease in the setting of aggressive immunosuppression responded to intravenous immunoglobulin. Antiphospholipid antibody-mediated endothelial cell activation in the absence of thrombosis may induce capillaritis as seen in these cases.


CONCLUSIONS
The syndrome of DAH and pulmonary capillaritis is further defined. Evidence supports a causative relationship between PAPS, pulmonary capillaritis, and DAH in the absence of thromboembolic disease. Further elucidation of a possible nonthrombotic mechanism of antiphospholipid antibody-mediated pathology is needed to guide future therapies for this unusual manifestation of PAPS.
Deane
Kevin D
KD
Rheumatology Division, University of Colorado School of Medicine, Denver, Colorado 80262, USA. kevin.deane@uchsc.edu
West
Sterling G
SG
D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000276:immunology*; D001706:Biopsy; D001999:Bronchoscopy; D002196:Capillaries / Q000473:pathology; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use; D006470:Hemorrhage / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008171:Lung Diseases / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011650:Pulmonary Alveoli / Q000473:pathology; D013902:Radiography, Thoracic; D014057:Tomography, X-Ray Computed; D014657:Vasculitis / Q000150:complications* / Q000175:diagnosis / Q000276:immunology
D017152:Antibodies, Antiphospholipid; D005938:Glucocorticoids; D007166:Immunosuppressive Agents