Investigation of reticulated platelets in dogs with steroid responsive meningitis-arteritis using ADVIA2120i

Abstract Background In steroid responsive meningitis-arteritis (SRMA), involvement of reticulated platelets is suspected based on the current knowledge of pathophysiology. Hypothesis/Objectives To compare reticulated platelets (whole blood) in dogs with SRMA to groups of healthy and diseased dogs. Furthermore, for dogs with SRMA, to investigate if reticulated platelets correlate with total nucleated cell count (TNCC) in cerebrospinal fluid. Animals Three groups were recruited from the University Hospital for Companion Animals or Anicura Holbæk Animal Hospital, Denmark; dogs with SRMA (n = 10), healthy dogs (n = 10), and dogs with signs of gastrointestinal disease and increased C-reactive protein in serum (n = 10). Methods This retrospective case–control study investigated differences in percentages of reticulated platelets and total number of reticulated platelets (#reticPLTs) between included groups using the Kruskal–Wallis test. In dogs with SRMA, TNCC in cerebrospinal fluid and correlation with reticulated platelet variables were investigated with Spearman’s rank correlation coefficient. Statistical significance was defined as P value .05. Results A statistically significant difference was found for #reticPLTs between dogs with SRMA (median 4.94 × 109 cells/L; 95% CI, 3.33-7.32) and dogs with signs of gastrointestinal disease (median 2.56 × 109 cells/L; 95% CI, 2.02-6.32) (P = .02). No significant correlation was found between reticulated platelet variables and TNCC in dogs with SRMA. Conclusions and clinical importance This study highlights potential involvement of reticulated platelets in SRMA pathophysiology. The identified difference in #reticPLT between dogs with SRMA and dogs with signs of inflammatory gastrointestinal disease might suggest differences in inflammatory pathways that are worth investigating in future research of SRMA pathophysiology.