Alpha-1 acid glycoprotein reduction differentiates recovery from remission in feline infectious peritonitis treatment (preprint)

ABSTRACT

Feline infectious peritonitis (FIP) is a systemic immune-mediated inflammatory perivasculitis which occurs in a minority of cats infected with feline coronavirus (FCoV). A variety of therapies have been employed to treat this condition, which previously was usually fatal, but no parameters for differentiating FIP recovery from remission have been defined to enable clinicians to decide when it is safe to discontinue treatment. This observational study shows that a consistent reduction of the acute phase protein alpha-1 acid glycoprotein (AGP) to within normal limits (WNL i.e. 500μg/ml or below), as opposed to duration of survival, distinguishes recovery from remission. AGP consistently reduced to WNL in 26 recovered cats but remained elevated in 16 cats in remission, dipping to normal once in two of the latter. Anaemia was present in 58% (23/40) of the cats, and resolved more quickly than AGP in six recovered cats. Lymphopenia was observed in 43% (16/37) of the cats and reversed in nine recovered cats, but none of the remission group. Hyperglobulinaemia was slower than AGP to return to WNL in the recovered cats. FCoV antibody titre was high in all 42 cats at the outset and decreased significantly in 7 recovered cats, but too slowly to be a useful parameter to determine discontinuation of anti-viral treatments. Conclusion: a sustained return to normal levels of AGP was the most rapid and consistent indicator for differentiating recovery from remission following treatment for FIP. This study provides a useful model for differentiating acute from chronic coronavirus disease using acute phase protein monitoring.