ABSTRACT Background Alpha‐1‐acid glycoprotein (AGP) is currently considered the most sensitive and specific inflammatory marker for diagnosing feline infectious peritonitis (FIP) and monitoring cats undergoing antiviral treatment. Various feline AGP assays have been validated, but currently, no assay compatible with biochemistry analyzers is available for the rapid analysis of high sample volumes in reference laboratories. Objectives This study aimed to validate a novel method of AGP measurement in cats using a latex agglutination immunoassay on the Cobas 6000 (Roche, Meylan, France) and establish a reference interval (RI). Methods Surplus serum/heparin plasma sample pools with low (~330 μg/mL), medium (~970 μg/mL), and high (~2600 μg/mL) AGP concentrations, determined by the latex agglutination immunoassay, were used to establish intra‐ and inter‐assay coefficient of variation (CV). Precision, linearity, recovery, and stability were assessed using pooled samples. RI was determined on surplus serum samples of 43 healthy cats. Results The intra‐assay CV was 7.6%, 6.1%, and 3.5%, and the inter‐assay CV was 6.4%, 5.1%, and 6.2% for low, medium, and high AGP concentrations, respectively. Excellent linearity ( R 2 = 0.99) was observed for AGP concentrations between 194.1 and 1412.4 μg/mL. The upper reference limit was 622.8 μg/mL (90% confidence interval 517.1–713.7 μg/mL). Age and sex did not have a significant impact on AGP concentrations. Conclusions The latex agglutination immunoassay allows a precise and high‐throughput analysis of AGP concentrations in cats. This assay will greatly enhance the availability of AGP measurements.
ABSTRACT Background Hemophagocytic syndrome (HPS)/hemophagocytic lymphohistiocytosis (HLH) is a life‐threatening hyperinflammatory syndrome characterized by immune dysregulation, cytokine overproduction, hemophagocytosis, cytopenias, and multiorgan dysfunction. Although diagnostic criteria are established in human medicine, standardized criteria and validated biomarkers are lacking in dogs and cats. Objective To review the pathogenesis, clinical and clinicopathologic features, diagnosis, and differential diagnoses of HPS/HLH, with emphasis on dogs and cats, and to propose a framework for establishing standardized diagnostic criteria for canine HPS. Methods Human and veterinary literature on HLH, HPS, and macrophage activation syndrome was reviewed, including diagnostic criteria, biomarkers, bone marrow morphology, immunohistochemistry, flow cytometry, and molecular diagnostics. Representative canine cases of secondary HPS and hemophagocytic histiocytic sarcoma were evaluated to illustrate diagnostic challenges. Results HPS results from dysregulated activation of cytotoxic lymphocytes and macrophages, with interferon‐γ playing a central role in sustaining hyperinflammation. In dogs and cats, HPS is most commonly associated with infections, neoplasia, and immune‐mediated disease. Clinical and laboratory findings are nonspecific, and although hemophagocytosis supports the diagnosis, it is neither required nor sufficient to establish HPS. Distinguishing reactive HPS from histiocytic neoplasia and other non‐neoplastic causes of hemophagocytic activity—including drug‐associated changes, post‐transfusion hemophagocytosis, and PIMA‐associated histiocytic activity—requires integration of cytomorphology, tissue distribution, immunophenotyping, and molecular diagnostics. Human HLH‐2004 criteria and the H‐score provide useful diagnostic frameworks, but neither has been validated for veterinary species. Conclusions HPS is a challenging and potentially fatal syndrome in dogs and cats, which requires comprehensive clinicopathologic evaluation. Prospective studies are needed to establish species‐specific diagnostic criteria and validate quantitative morphologic, immunophenotypic, molecular, and biomarker‐based approaches to distinguish HPS from infectious, immune‐mediated, and neoplastic disorders in which phagocytic activity is prominent.
BACKGROUND:In laboratory practice, complete blood count (CBC) analysis is not always immediate, and underfilled or overfilled blood tubes may yield misleading results. OBJECTIVES:To assess CBC stability in rats and rabbits over 24 h and determine the effect of under- or over-filled tubes on alterations in the results, demonstrating which indices remain reliable under these conditions. METHODS:Blood was collected into EDTA-K2 vacuum tubes from rats (tubes: 0.5, 1.0, 1.5, 2.0 mL) and rabbits (tubes: 2.0, 2.5 mL). All tubes were stored at 4°C and analyzed at 0, 4, 8, and 24 h using a CBC analyzer. RESULTS:Statistically significant changes (p < 0.05) were observed: In rats, white blood cell (WBC), neutrophil, lymphocyte, monocyte, red blood cell (RBC), hematocrit (HCT), and hemoglobin (Hb) counts were sensitive to blood sampling volume and decreased with smaller volumes. WBC, neutrophil, RBC, HCT, and platelet (PLT) counts showed no statistically significant change within 24 h. In rabbits, blood sampling volume and storage time independently influenced WBC, neutrophil, lymphocyte, and Hb counts. RBC, HCT, and PLT counts showed no statistically significant change within 8 h. CONCLUSIONS:WBC, neutrophil, lymphocyte, RBC, HCT, and Hb are volume-sensitive in rats and rabbits, whereas PLT counts are unaffected by volume. Therefore, blood samples with insufficient or excessive fill may still be used for PLT measurement, but results for the other indices are not recommended.
An 8-year-old Whippet crossbreed was presented with a month's history of collapsing episodes and altered mentation. Clinical improvement was noted upon administration of prednisolone prior to referral. Neurologic examination was compatible with a multifocal intracranial disease. Magnetic resonance imaging revealed thickening of the dura mater around the left parietal and temporal cerebral cortex, left piriform lobe, and cerebellar hemispheres. Cerebrospinal fluid (CSF) analysis revealed marked eosinophilic pleocytosis with increased protein concentration. Infectious diseases were ruled out. Thoracic and abdominal imaging did not reveal any significant abnormalities. The dog was euthanized 4 days after diagnosis. Post-mortem examination revealed diffuse, severe, subacute to chronic eosinophilic pachymeningitis and generalized eosinophilic disease. Eosinophilic CSF pleocytosis has been reported in a number of inflammatory (sterile and infectious) and neoplastic canine encephalopathies. To the best of our knowledge, eosinophilic pleocytosis has not been reported in cases of hypertrophic pachymeningitis in dogs.
