Article Figures & Data
Figures
- FIG. 1.
(A) Histological pattern of a superficial inguinal lymph node of a healthy pig. Follicular and interfollicular areas are clearly differentiated. (B) Moderate lymphocyte depletion (score 2) in a superficial inguinal lymph node of a pig with PMWS. Follicles are still perceptible, but cellular depletion is evident in all the lymphoid parenchyma. (C) Severe lymphocyte depletion (score 3) in a superficial inguinal lymph node of a pig with PMWS. No follicles or medulla-like tissues are evident in the lymphoid tissue. HE staining was used for all panels. Magnification, ×40.
- FIG. 2.
High (A) and low (B) levels of PCV2 nucleic acid in tissue from the tonsils of a pig with PMWS. Results were obtained by PCV2 ISH. All panels show fast green counterstaining. Magnification, ×400.
- FIG. 3.
Distribution of individual results (percentage of cells for each animal) with respect to the different lymphocyte subsets. The large open circles comprise the clusters of pigs with the lowest relative proportions of peripheral blood lymphocyte subsets, pigs that thereby differ from the other pigs in the study. +ve, positive; −ve, negative.
Tables
- TABLE 1.
Percentages of lymphocyte subsets of PBMC among the different pig groups
Group (no. of pigs) Percentage (mean ± SD) of indicated lymphocyte surface antigen marker in PBMCa CD4+ CD8+ CD4+ CD8+ IgM+ PCV2 positive (24) 5.0 ± 4.3 A 17.6 ± 14.3 A 1.4 ± 1.6 A 8.0 ± 6.4 A* High PCV2 (17)b 5.1 ± 4.4 A 16.4 ± 13.7 A 1.3 ± 1.2 A 6.5 ± 6.5 C Low PCV2 (7)b 4.8 ± 4.5 A 20.5 ± 16.4 B 1.7 ± 1.2 A 11.6 ± 5.1 A PCV2 negative (17) 6.7 ± 3.8 A 40.8 ± 18.7 C 3.2 ± 2.9 B 14.3 ± 9.6 B Healthy control (8) 15.2 ± 4.1 B 27.2 ± 7.8 C 5.2 ± 1.7 B 12.5 ± 5.3 AB* ↵a Values followed by the same letter (A, B, or C) are statistically similar, while different letters for values within the same lymphocyte subset indicate significant differences in the mean values (P ≤ 0.05). *, P = 0.09.
↵b The PCV2-positive group was subcategorized with respect to the apparent level of PCV2 stained by the ISH technique.
- TABLE 2.
Distribution of pigs according to the histopathologic stage of cellular depletion in different lymphoid tissuesa
Group (no. of pigsb) No. of pigs showing lymphocyte depletion in indicated tissue Superficial inguinal LNc Mesenteric LN Peyer's patches Tonsil Spleen (PALSd) B zonee T zonef B zone T zone B zone T zone B zone T zone PCV2 negative (17) 5 1 10 4 7 8 3 2 3 PCV2 positive (24) 19g 17g 19 17g 18h 19h 17g 14g 13h ↵a Since healthy control pigs showed no lesions, results for them have been excluded from the table, and the results of the statistical analysis reflect a comparison, between the PCV2-negative and PCV2-positive wasted-pig groups. P values were obtained from 2-by-2 contingency tables.
↵b Total number of pigs in each group, including those not showing lymphocyte depletion.
↵c LN, lymph node.
↵d PALS, periarteriolar lymphoid sheaths.
↵e B zone, B-cell-dependent area.
↵f T zone, T-cell-dependent area.
↵g P < 0.001.
↵h P < 0.05.
- TABLE 3.
Comparison of the degrees of lymphocyte depletion of different lymphoid tissues with respect to the apparent amount of PCV2 DNA genome observed after ISH
Level of PCV2 DNA (no. of pigsb) No. of PCV2-positive pigs showing indicated degree of lymphocyte depletion in indicated tissuea Superficial inguinal LNc Mesenteric LN Peyer's patches Tonsil Spleen (PALSd) B zonee T zonef B zone T zone B zone T zone B zoneg T zoneh 1 2 or 3 1 2 or 3 1 2 or 3 1 2 or 3 1 2 or 3 1 2 or 3 1 2 or 3 1 2 or 3 1 2 or 3 Low (7) 4 0 0 0 3 0 1 0 1 1 1 1 3 0 1 0 1 0 High (17) 0 15 8 9 0 17 1 16 0 16 1 16 1 13 4 9 5 7 ↵a Score of lymphocyte depletion degree: 1, slight; 2, moderate; 3, severe.
↵b Total number of pigs, including those not showing lymphocyte depletion.
↵c LN, lymph node.
↵d PALS, periarteriolar lymphoid sheaths; P = 0.07.
↵e B zone, B-cell-dependent area.
↵f T zone, T-cell-dependent area.
↵g P < 0.01; for other groups, P < 0.001, except as indicated.
↵h P < 0.05.
