Fig. 4.
Summary of hematologic data from dog E399, which developed marrow aplasia after mHA-sensitized DLI.
(A) Peripheral blood counts recorded from the time of mHA-sensitized DLI. Total white blood cell count (μL), absolute neutrophil count (μL), and platelet count (μL) are plotted on the left y axis (log scale). Hematocrit is plotted on the right y axis. Arrows indicate infusion of donor marrow in an attempt to restore hematopoiesis. There was no marked recovery of absolute neutrophil count after marrow infusions. Recombinant granulocyte colony-stimulating factor was administered for the period shown. Dog E399 was humanely killed because of pneumonia 67 days after mHA-sensitized DLI. (B) Representative microsatellite marker studies at selected times. Dog E399 received 4.5-Gy lymph node irradiation, DLA-identical littermate marrow, and postgrafting therapy with mycophenolate mofetil and cyclosporine for 4 weeks and 5 weeks, respectively. Low-level donor chimerism (4%-5%) was unchanged after DLI given 25 weeks after grafting (data not shown). Skin-graft–sensitized mHA-sensitized DLI was given in week 56. After the onset of pancytopenia in week 59, complete donor chimerism was observed in PBMC, granulocyte, and bone marrow fractions. (C) Photomicrograph of biopsy specimen obtained at necropsy from anterior rib marrow of dog E399 showing hypocellular (5%) marrow. Also shown is a rare focus of primarily lymphoid hematopoiesis observed in 2 of 10 fields (arrows). The remaining marrow space contains predominantly red blood cells and few fibroblasts. Biopsy specimens (not shown) from the posterior iliac crest showed complete absence of hematopoiesis. Bar indicates 1 mm. (Stain, hematoxylin & eosin; magnification × 25.)