[Analysis of risk factors and prognosis of cytomegalovirus infection post umbilical cord blood stem cell transplantation in children with primary immunodeficiency diseases].

To investigate the risk factors and outcomes of cytomegalovirus (CMV) infection post umbilical cord blood stem cell transplantation (UCBT) in children with primary immunodeficiency diseases (PID). Clinical data of 143 PID children who received UCBT in the Children's Hospital of Fudan University from January 2015 to June 2020 were collected retrospectively. CMV-DNA in the plasma was surveilled once or twice a week within 100 days post-UCBT. According to the CMV-DNA test results, children were divided into the CMV-infected group and the CMV-uninfected group. The incidence and risk factors of CMV infection were analyzed. At 1-month post-UCBT, the absolute lymphocyte count, ratio of lymphocyte subsets and immunoglobulin levels were compared between those whose CMV infection developed 1-month later post-UCBT and those not. Mann-Whitney test and chi-squared test were used for comparision between groups. Kaplan-Meier survival analysis was used to analyze the impact of CMV infection on survival. Among 143 patients, there were 113 males and 30 females, with a age of 14 (8, 27) months at UCBT. Chronic granulomatosis disease (=49), very-early-onset inflammatory bowel disease (=43) and severe combined immunodefiency (=29) were the three main kinds of PID. The rate of CMV infection was 21.7% (31/143), and the time of infection occurring was 44 (31, 49) days post-UCBT. The incidence of recurrent CMV infection was 4.2% (6/143) and refractory CMV infection was 4.9% (7/143).There was no significant difference in the first time CMV-DNA copy and peak CMV-DNA copy during treatment between the recurrent CMV infection group and the non-recurrent CMV infection group (32.8 (18.3, 63.1)×10 22.5 (13.2, 31.9)×10 copies/L, =-0.95, =0.340;35.2 (20.2, 54.6)×10 28.4 (24.1, 53.5)×10copies/L, =-0.10, =0.920), so were those between the refractory CMV infection group and non-refractory CMV infection group (21.8 (13.1, 32.2)×10 25.9 (14.2, 12.2)×10copies/L, =-1.04, =0.299; 47.7 (27.9, 77.6)×10 27.7 (19.7,51.8)×10copies/L, =-1.49, 0.137). The CMV-infected group accepted more reduced-intensity conditioning (RIC) regimen than the CMV-uninfected group (45.2% (14/31) . 25.0% (28/112), χ=4.76, 0.05). The rate of CMV-seropositive recipients and Ⅱ-Ⅳ acute graft versus host diseases (aGVHD) are significantly higher in the CMV-infected group than the CMV-uninfected group (100% (31/31) . 78.6% (88/112), 64.5% (20/31) . 26.8% (30/112), χ=7.98,15.20, both <0.05). The follow-up time was 31.6 (13.2, 45.9) months, CMV infection had no effect on overall survival (OS) rate (χ=0.02, =0.843). There was significant difference in the survival rate among three groups of refractory CMV infection, non-refractory CMV infection and the CMV-uninfected (4/7 95.8% (23/24) 86.6% (97/112), χ=5.91, =0.037), while there was no significant difference in the survival rate among three groups of recurrent CMV infection, non-recurrent CMV infection and the CMV-uninfected (5/6 88.0% (22/25) 86.6% (97/112), χ=0.43, =0.896). Children who developed CMV infection after 30 days post-UCBT had lower absolute count and rate of CD4 T cells and immunoglobulin G (IgG) level than those in the CMV-uninfected group (124.1 (81.5, 167.6) ×10 175.5 (108.3, 257.2) ×10/L, 0.240 (0.164, 0.404) 0.376 (0.222, 0.469), 9.3 (6.2, 14.7) 13.6 (10.7, 16.4) g/L, =-2.48, -2.12,-2.47, all <0.05), but have higher rate of CD8T cells than those in CMV-uninfected group (0.418 (0.281, 0.624) 0.249 (0.154, 0.434), =-2.56, =0.010). RIC regimen, grade Ⅱ-Ⅳ aGVHD and CMV-seropositive recipients are the main risk factors associated with CMV infection in PID patients post-UCBT. Survival rate of children with refractory CMV infection after UCBT is reduced. Immune reconstitution in children after UCBT should be regularly monitored, and frequency of CMV-DNA monitoring should be increased for children with delayed immune reconstitution.