Changes in peripheral blood leukocyte populations in pigs with natural postweaning multisystemic wasting syndrome (PMWS)

The objective of the present study was to analyze, by flow cytometry, chang es in PBMC subsets in pigs having postweaning multisystemic wasting syndrom e (PMWS), a new condition associated to porcine cireovirus type 2 (PCV2) in fection. Thirteen acutely PMWS affected pigs were selected from a farm sero negative to porcine reproductive and respiratory syndrome virus (PRRSV) and to Aujeszky's disease virus (ADV); 11 clinically healthy pigs were selecte d from a high health farm with no history of PMWS and free of the major swi ne pathogens, and used as a control group. All pigs were necropsied, and ti ssue samples were fixed in formalin; blood with EDTA anticoagulant was used to perform the now cytometric analysis. PBMC were incubated with mAb again st porcine CD3, CD4, CD8, CD25, CD45, IgM, SWC3, and SLA-Class II. Flow cyt ometric analysis showed substantial changes in leukocyte subsets in the per ipheral blood of PMWS-affected pigs, which were characterized by an increas e of monocytes, a reduction of T (mainly CD4(+)) and B-lymphocytes, and the presence of low-density immature granulocytes. Altogether, these changes w ould suggest an inability of acutely PMWS-affected pigs to mount an effecti ve immune response. (C) 2001 Elsevier Science B.V. All rights reserved.