The idea that histopathologic patterns might provide treatment options and pathogenetic insights in rheumatic disease is drawn from studies of idiopathic disease, in which histologic patterns have had a major role in prognostic evaluation. There is now a pathogenetic dichotomy in idiopathic disease. The “epithelial/fibrotic” pathogenetic model associated with usual interstitial pneumonia (UIP, the pattern of idiopathic pulmonary fibrosis, can be contrasted with the “inflammatory/fibrotic” model of other fibrotic lung diseases, including organizing pneumonia (OP) and non-specific interstitial pneumonia (NSIP). In these latter diseases, it is likely that inflammation precedes and leads to fibrosis.
Do these distinctions apply equally to the rheumatic diseases? To explore whether parallel pathogenetic insights have developed:
1) The prevalence of histologic patterns in individual rheumatic diseases will be examined in relation to the patterns of disease progression in those diseases, including a) the usual patterns of disease progression and b) fatal acute exacerbations
2) Differences in the efficacy of therapy in different histologic sub-types (whether in achieving a response or preventing disease progression) will be compared between idiopat6hic disease and rheumatic disease.
For both questions, some similarities exist between idiopathic and rheumatic diseases - but the resulting pathogenetic insights in rheumatic diseases are tentative, rather than definitive.
Regarding treatment options
1) As the selection of treatment options is profoundly influenced by prognostic evaluation, the prognostic value of the histologic pattern, and also the CT estimation of the likely histologic pattern, will be reviewed in the rheumatic diseases. It is in rheumatoid arthritis, above all other individual rheumatic diseases, that the most evidence exists of parallelism with idiopathic disease.
2) The degree to which treatment outcomes in relation to underlying pattern influence the management strategy will be compared between rheumatic and idiopathic disease and from the similarities that exist, it will be argued that new therapies are definitely required for typical rheumatoid lung whereas existing therapies, although far from ideal, are more often effective in other rheumatic diseases.
Disclosure of Interest None Declared
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.