Table 3.

Comparison between ILD in SLE and SSc.

	SLE	SSc
Frequency	2–4%	75%
Risk factors	Older age Longstanding disease	dcSSc male sex African American race Nailfold capillary abnormalities Digital ulcers Longer disease duration Pulmonary hypertension
Genetics	-	HLA-DRB1*11 HLA-DRB1*301
Antibodies	Anti-dsDNA Anti-La Anti-Scl-70 Anti-U1RNP Anti-Sm lupus anticoagulant	Anti-topoisomerase I Anti-neutrophil cytoplasmic antibody Anticardiolipin Anti-Ro52 Anti-NOR90 Anti-U11/U12 Anti-Th/To Anti-polymyositis-scleroderma
Type	NSIP organizing pneumonia follicular bronchitis	NSIP UIP PPFE
Onset	Within an average of 7.7 years of SLE onset	Within 5 years of the first non-Raynaud phenomenon symptom.
Pathology	An aberrant inflammatory response due to cytokine release; The impaired apoptosis and abnormal fibroblast proliferation leading to alveolar injury was described.	An injury to the alveolar epithelium, the vasculature, or both have been proposed as the initial event, followed by an aberrant immune response with fibroblast recruitment and activation. Extracellular matrix overproduction and an important scarring process replace the standard pulmonary architecture. The fibrotic variant of NSIP is more frequent than the cellular variant. Survival is not different between the two types of NSIP variants.
Clinical	May be asymptomatic Dyspnoea Tachypnea Cough Possible evidence of scleroderma	Dyspnoea Non-productive cough fatigue Velcro-like crackles on auscultation
Treatment	Hydroxycholoquine Glucocorticoids CYC MMF Belimumab/Rituximab IVIg Antifibrotic treatments Lung transplantation	CYC MMF Rituximab Nintedanib Bone marrow or lung transplantantion
Diagnosis	HRCT Pulmonary function tests	HRCT Pulmonary function tests

dcSSc—diffuse systemic sclerosis; lcSSc—limited systemic sclerosis; NSIP—non-specific interstitial pneumonia; CYC—cyclophosphamide; MMF—mycophenolate mofetil; IVIg—intravenous immunoglobulin; HR-CT—high resolution computed tomography; UIP—usual interstitial pneumonia; PPFE—pleuroparenchymal fibrosis.