  
Lupus Nephritis
Systemic Lupus Erythematosus (SLE) is
a complex multi-system disease. This complexity makes it difficult to monitor.
In particular, there are problems in differentiating potential reversible organ
dysfunction, due to disease activity, from irreversible organ damage.
Lupus nephritis is the most serious manifestation of the disease, which, if
left untreated, can lead to kidney failure, requiring dialysis. It is a
complicated disease as patients typically fluctuate between periods of intense
disease activity, (flares), when the patient's own immune system is actively
attacking and causing damage in their kidney, interspersed with periods of
remission. Clinicians estimate that one third to one half of lupus patients have
lupus nephritis.
There has been no new approved treatment for SLE or lupus nephritis in the
United States in over thirty years. Current treatments involve the off-label use
of existing cancer drugs such as steroids, cyclophosphamide, and other
immunosuppressant drugs such as azathioprine.
There is also a problem in defining the term ‘disease
activity’ which contributes to an overall poor correlation between physicians’
scores when assessing patients using a semi-quantitative clinical rating scale.
Over the last three decades, the British Isles Lupus Assessment Group (BILAG)
has developed standardised quantitative measures of clinical disease activity in
SLE, in the process defining terms, which enable physicians to communicate in a
common language.
The BILAG Index was developed into a software
application by ADS-Limathon and is available as BLIPS. The BILAG Index is a comprehensive computerised index for measuring for measuring clinical disease activity in Systemic Lupus Erythematosus
(SLE). It was developed according to the principle of the 'physicians intention to treat'. The index allocates separate alphabetic scores to each of eight organ-based systems. A numeric score and total score has been added in BLIPS though this was not originally calculated. A study in 1993 demonstrated good 'between-rater' reliability for the BILAG index for each organ based system. There was no evidence of bias between observers. The BILAG Index had good overall sensitivity (87%) and specificity (99%) when compared with the 'Gold Standard' criterion (starting or increasing disease-modifying therapy). There were high positive predictive values overall, and for each organ-based system, with the exception of the neurological system. This exception can be explained by the activities of anticoagulants and other
non-immunosuppresant therapies, which were used, but not evaluated.
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