An Experimental And Clinical Study Of CMV Infection After Allogeneic Hematopoietic Stem Cell Transplantation

Objective: (1) To establish quick and reliable diagnostic methods for detecting the cytomegavirus (CMV) infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and to evaluate their clinical value in early diagnosis of CMV infection; (2) To study the distribution of CMV glycoprotein B (gB) genotypes in the patients with CMV infection after allo-HSCT and the correlation between genotypes and pathogenesis of CMV intermediate pneumonia (IP) as well as GVHD.Methods: (1) From March 2001 to December 2003, Seventy-four patients undergoing allo-HSCT were enrolled in this study. After allo-HSCT, all the patients were detected for CMV gB DNA in peripheral blood by haplo-nested PCR methods and 35 of 74 patients for CMV PP65 antigen in peripheral blood by the fluorescent immunohistochemistry (FIHT) assay. The positive rate and correspondence of these two methods were evaluated. (2) The incidence of CMV infection in different types of allo-HSCT was compared; the incidence and mortality of the CMV disease were investigated. (3) The CMV gB DNA positive samples were screened, which were sufficient for enzyme digestion. Glycoprotein B typing was performed through digesting PCR products with Rsa I and Hinf I . The distribution of gB genotypes and the correlation between genotypes and pathogenesis of CMV-IP as well as GVHD were analyzed.Results: (1) In 35 of 74 patients who were tested for CMV infection by two assays at the same time, the CMV-viremia was first detected at amedian of 36 days after transplantation by FIHT assay and 26 days by haplo-nested PCR assay during the follow-up time of 90-720 days. The median time of positive persistence was 19 days by FIHT assay and 28 days by haplo-nested PCR assay. The significant difference of them was observed (P<0.05). The corresponding of the two assays was 88.57%. The difference of the two methods was not significant statistically. The incidence of CMV-agtigenemia and CMV-DNAemia were 65.71% and 71.43% during the follow-up days, respectively. (2) The infection rate in the nonmyeloablative allogeneic peripheral stem cell transplantation (NST) group was 78.95%, in the group of related peripheral blood stem cell transplantation (R-PBSCT) and/or related bone marrow transplantation (R-BMT) 48.57%, and in the group of unrelated bone marrow transplantation (UR-BMT) 61.54%. The infection rate of CMV in the UR-BMT group was higher than that in R-PBSCT and/or R-BMT group, but without significant difference (P>0.05). The infection rate of CMV in the NST group was significantly higher than in R-PBSCT and/or R-BMT group (PO.05), but only a litter higher than in UR-BMT group (P>0.05). Both CMV-antigen and CMV-DNA were detected in all seven patients undergoing haploidentical hematopoietic stem cell transplantation (Hi-HSCT). (3) Forty-seven patients (63.51%) suffered from CMV infection. All the patients except one received preemptive therapy. After two weeks to six month, the infection reoccurred in 12 patients who had been cured. CMV-IP developed in 20 patients (27.03%). The median day of onset of CMV-IP was 65 days. Seven patients (35%) died. (4) The PCR products of thirty-eight patients were digested with enzyme, the distribution of gB genotypes was as follows: I (gBl) 19/38 (50.0%), II (gB2) 3/38 (7.89%), III (gB3) 14/38 (36.84%), and unclassification 2/38 (5.27%). The incidence of CMV-IP in patients of gB3 was significantly higher than in gBland the symptoms of CMV-IP in gB3 were more severe than in gBl. The incidences of GVHD were not different significantly between the patients of gBl and those of gB3.Conclusion: (1) Both FIHT and haplo-nested PCR assays were quick and reliable diagnostic methods for detecting the CMV infection after allo-HSCT and their correspondence was good. However CMV infection could be found earlier by haplo-nested PCR assay than by FIHT assay. (2) The infection rate of CMV is high after allo-HSCT and might be different in different types of allo-HSCT. (3) The distribution of gB genotypes was different in the patients with CMV infectio...