TNF and hypersensitivity pneumonitis: As shown in a recent meta-analysis reviewing the usefulness of BAL in monitoring disease activity in SSc, the presence of alveolitis and increased levels of inflammatory markers in BAL, including tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin 7 (IL-7) and interleukin 8 (IL-8), were associated with impaired lung function, increased symptoms and/or worse radiological features6.