Use of anti-coronavirus antibody testing of cerebrospinal fluid for diagnosis of feline infectious peritonitis involving the central nervous system in cats.
OBJECTIVE
To assess the use of measuring anti-coronavirus IgG in CSF for the diagnosis of feline infectious peritonitis (FIP) involving the CNS in cats.


METHODS
Prospective study.


METHODS
CSF and serum samples from 67 cats.


METHODS
CSF and serum samples were allocated into 4 groups: cats with FIP involving the CNS (n = 10), cats with FIP not involving the CNS (13), cats with CNS disorders caused by diseases other than FIP (29), and cats with diseases other than FIP and not involving the CNS (15). Cerebrospinal fluid was evaluated for concentrations of erythrocytes, leukocytes, and total protein. Anti-coronavirus IgG was measured in CSF and serum by indirect immunofluorescence assay.


RESULTS
CSF IgG (range of titers, 1:32 to 1:4,096) was detected in 12 cats, including 6 cats with neurologic manifestation of FIP, 4 cats with FIP not involving the CNS, and 2 cats with brain tumors. Cerebrospinal fluid IgG was detected only in cats with correspondingly high serum IgG titers (range, 1:4,096 to 1:16,384) and was positively correlated with serum IgG titers (r = 0.652; P < 0.01), but not with any other CSF parameter. Blood contamination of CSF resulted in < or = 333 erythrocytes/microL in cats with CSF IgG.


CONCLUSIONS
The correlation between serum and CSF IgG and the fact that CSF IgG was detected only in strongly seropositive cats suggested that CSF anti-coronavirus IgG was derived from blood. Measurement of anti-coronavirus IgG in CSF was of equivocal clinical use.
Boettcher
Irene C
IC
Clinic of Small Animal Medicine, Ludwig-Maximilians-University, Veterinaerstr. 13, 80539 Munich, Germany.
Steinberg
Tanja
T
Matiasek
Kaspar
K
Greene
Craig E
CE
Hartmann
Katrin
K
Fischer
Andrea
A
D000367:Age Factors; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood* / Q000134:cerebrospinal fluid*; D002415:Cats; D002555:Cerebrospinal Fluid / Q000276:immunology* / Q000821:virology; D016765:Coronavirus, Feline / Q000276:immunology*; D003937:Diagnosis, Differential; D016766:Feline Infectious Peritonitis / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis; D005260:Female; D007074:Immunoglobulin G / Q000097:blood / Q000134:cerebrospinal fluid; D008297:Male; D009422:Nervous System Diseases / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000662:veterinary*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012737:Sex Factors
D000914:Antibodies, Viral; D007074:Immunoglobulin G