The patient was a 69-year-old woman with a past medical history significant for osteopenia, chronic lower back pain and diverticulosis who presented with weakness and fatigue for approximately one month accompanied by low blood pressure (70/40 mm Hg) and mild shortness of breath. The patient had a history of a left heart catheterization in 2007 which showed dilated nonischemic cardiomyopathy with an ejection fraction of approximately 30%. On the last admission prior to transplantation, the patient was hypotensive and had an ejection fraction of 15%. She was started on dobutamine, and an implantable cardioverter-defibrillator device was placed. The patient was ultimately maintained on milrinone and evaluated for orthotopic heart transplantation.
Once a heart became available for transplantation, the patient was started on prednisone, MMF, and tacrolimus. A heart from a male donor was transplanted without complication. The explanted heart showed dilated cardiomyopathy with cardiomyopathy of end-stage heart failure. The patient's postoperative course was complicated by an upper extremity deep venous thrombosis for which the patient received enoxaparin 60 mg subcutaneous every 12 h. The patient was discharged to home on postoperative day eight on valgancyclovir, pravastatin, iron sulfate, enoxaparin, nystatin, diltiazem-SR, Bactrim-DS, aspirin, lexapro, and an immunosuppressive regimen including tacrolimus 4 mg every 12 h, a prednisone taper, and MMF 750 mg every 12 h.
Two months after transplantation, the patient presented with a two-week history of watery stools and diarrhea consisting of four to five episodes after each meal with occasional maroon blood in the stool. These episodes were preceded by cramping, nonradiating abdominal pain and were not accompanied by fevers, chills, nausea, vomiting, hematemesis, melena, chest pain, shortness of breath, dizziness, palpitations, dysuria, or hematuria. She had a history of hemorrhoids and diverticulitis in the past and had also had a recent colonoscopy which was negative. There was no history of NSAID use or peptic ulcer disease. Microscopic studies of her stool were negative for Giardia lamblia, Entamoeba histolytica, ova and parasites, Salmonella spp., Shigella spp., Cryptosporidium, Campylobacter spp., as well as C. difficile toxin and antigen and Rotatvirus antigen. There was no increase in white blood cells in the stool. The stool was Hemoccult-positive. An abdominal X-ray demonstrated no intestinal obstruction. A colonoscopy performed at this time showed severe diverticulosis, and biopsies revealed colonic mucosa with crypt apoptosis, lamina propria fibrosis, and inflammatory cell infiltrate which could be consistent with GVHD. No evidence of cytomegalovirus was identified. The patient was treated with three days of outpatient steroids. Her MMF was held prior to discharge due to leukopenia.
The patient was readmitted three days later with bloody, Hemoccult-positive stools. Colonoscopy and esophagogastroduodenoscopy failed to demonstrate a source of bleeding. It was felt that the patient's symptoms, including bleeding and bloating, were due to MMF, and her immunosuppressive regimen was change to tacrolimus and azathioprine with amelioration of her gastrointestinal symptoms.
FISH for the X and Y chromosome was performed on paraffin-embedded tissue prepared in the histology lab at Thomas Jefferson University Hospital. The slides were subjected to deparaffinization using Hemo-D (three washes, 10 min each) and 100% ethanol (two washes, 5 min each). The slides were pretreated as follows: 0.2 N HCl for 20 min at room temperature followed by a wash in 2× SSC for 3 min at room temperature; 2× SSC at 73°C for 30 min; 30% pepsin in 2× SSC for 30 min at 45°C followed by a wash in 2× SSC for 3 min at room temperature; proteinase K for 20 min at 45°C followed by a wash in 2× SSC for 3 min at room temperature. The slides were postfixed in 10% formalin for 10 min at room temperature and washed in 2× SSC for 3 min at room temperature. The slides were dehydrated and denatured and prepared for hybridization with CEP X and CEP Y Dual color probe (1:10 dilution) (Vysis, Des Plaines, Ill., USA) overnight at 37°C. The slides were washed in posthybridization buffer for 2 min at 72°C and counterstained with 4(,6-diamidino-2-phenylindole.
Microscopic examination of the random colon biopsies revealed colonic mucosa with areas of crypt apoptosis and lamina propria fibrosis (). There was a mixed inflammatory cell infiltrate predominately composed of mature lymphocytes. No viral inclusions were identified, and a special immunohistochemcial stain for cytomegalovirus was negative (data not shown).
Fig. 1 GVHD-like histology in MMF toxicity of the colon. a There is a mixed inflammatory infiltrate composed primarily of mature lymphocytes and eosinophils. The arrow indicates an apoptotic enterocyte within a crypt. The inset shows a higher magnification of (more ...)
Because the patient was female and the donor was male, FISH was performed to detect the presence of the Y chromosome in lymphocytes present in the biopsy material. Gender-mismatched transplantations, in which a female patient receives a male donor organ, offer a unique opportunity to investigate recipient tissues, because the detection of the Y chromosome discriminates the cells of donor origin from recipient-derived cells. No Y chromosome signals were detected, indicating there was no significant infiltrate by cells derived from the male heart donor ().