Thrombotic microangiopathy (TMA) is a lethal transplantation-associated complication which exactly likes acute intestinal graft-versus-host disease (GVHD) in the clinical manifestation. 373 consecutive patients with hematological diseases received family HLA matched or mismatched HCT from May, 2002 to July, 2004. To analyse the clinical and pathological characteristics of TMA, 30 patients who suffered from severe diarrhea and received colonoscopic examination and gut biopsy were retrospectively analyzed. The results indicated that 7 patients originally diagnosed as gut GVHD showed the pathological evidence of enteric TMA. The incidence of TMA was 7 out of 30 specimen (23.3%). Pathological evidence of enteric TMA shown microvascular disorder characterized by thrombus in the capillary without infiltration of lymphocytes and perivascular hemorrhages in the mucosa, swelling and focal denudation of epithelial cells. All patients with TMA were associated with cytomegalovirus (CMV) antigenemia/disease. Among these patients, 4 cases, who only showed TMA without the evidence of gut GVHD pathologically, displayed treatment-resistant bloody diarrhea, renal failure, veno-occlusive disease, hemorrhagic cystitis, hemolytic anemia as well as thrombocytopenia. But the other 3 cases, with co-existence of both TMA and GVHD pathological characteristics had better treatment response. Survival analysis indicated that 3 patients with TMA-GVHD survived for 461 to 536 days but three out of four TMA patients died from VOD with liver failure as well as multiple organ failure during 101 to 254 days after HCT. In conclusion, to better diagnose those patients with severe and refractory diarrhea following HCT, pathological examination may indicate crux evidence to identify intestinal TMA from gut GVHD. Furthermore, this primary report has first evidenced that TMA and TMA-GVHD are two pathologically well-recognized subtypes with the difference between the pathological characteristics, treatment response and clinical outcomes.
Graft vs Host Disease ; etiology ; Hematopoietic Stem Cell Transplantation ; adverse effects ; Humans ; Intestinal Diseases ; diagnosis ; etiology ; pathology ; Purpura, Thrombotic Thrombocytopenic ; diagnosis ; etiology ; pathology ; Reference Standards ; Retrospective Studies ; Thrombosis ; diagnosis ; etiology ; pathology

BACKGROUND: The impact of HLA and KIR ligand mismatching on the outcome of hematopoietic stem cell transplantation (HSCT) remains unclear. Previous reports have identified considerable ethnic differences in the impact of HLA and KIR ligand mismatches, as well as KIR ligand status, on HSCT; however, to date, no data has been acquired in Korean adult patients. METHODS: We investigated the association of high-resolution HLA matching on five loci (HLA-A, -B, -C, -DRB1, and -DQB1), KIR ligand mismatching, and KIR ligand status on the outcome of allogeneic HSCT from unrelated donors in 154 Korean adult patients treated at Seoul National University Hospital. RESULTS: In a multivariate analysis, less than 9/10 allelic matches in five HLA loci was an independent risk factor for acute graft-versus-host disease (GVHD) (grade II to IV) (P=0.019, odds ratio [OR]=2.7). In addition, HLA-A allele mismatching was increasingly prevalent in patients with acute GVHD compared to patients without (61.9% vs. 34.5%, P=0.06). For KIR ligand status, the patient and donor combination of both C1/C1 ligands showed better event-free and overall survival than combinations with C2 ligand patients or donors (P=0.048, P=0.034, respectively) by log-rank test. CONCLUSIONS: Korean adult transplant patients with less than 9 of 10 HLA allele matches in the HLA-A, -B, -C, -DRB1, and DQB1 loci have a higher likelihood of developing acute GVHD (grade II to IV). Impact of KIR ligand status on clinical outcome should be further studied in a larger patient population.
Adolescent ; Adult ; Alleles ; Female ; Genetic Loci ; Graft vs Host Disease/etiology ; HLA Antigens/*genetics/metabolism ; *Hematopoietic Stem Cell Transplantation/adverse effects/standards ; Histocompatibility Testing ; Humans ; Kaplan-Meier Estimate ; Leukemia/mortality/therapy ; Male ; Middle Aged ; Multivariate Analysis ; Receptors, KIR/*chemistry/metabolism ; Republic of Korea ; Risk Factors ; Transplantation, Homologous ; Young Adult