MMP9 and Recurrent lower respiratory tract infections: Previous studies have indicated that the use of oral steroids is associated with increased morbidity and mortality from lower respiratory tract infections [12,47], and we have found in a separate, previously described population of well-characterised RA patients [48] that those taking oral steroids have significantly higher levels of MMP-8 and MMP-9 than those not taking these drugs (unpublished observations).