Ps1277 evaluation of the immunity to measles, mumps and rubella in adult patients after allogeneic hematopoietic stem cell transplantation

Background: Several studies have shown that most patients become seronegative to measles, mumps, and rubella (MMR) during long‐term follow‐up after allogeneic hematopoietic stem cell transplantation (allo‐HCT). However, these studies mainly targeted pediatric patients and limited data were available for adult patients. Unfortunately, the epidemics of measles or rubella occasionally occur in Japan, because there are some generations with low seropositivity rates due to prior Japanese vaccination policy. Therefore, vaccination against MMR may be important for allo‐HCT patients. Although the vaccination against MMR is recommended for allo‐HCT patients without active chronic GVHD after the cessation of immunosuppressive therapy at least 24 months after HSCT, it is not routinely performed in adult allo‐HCT patients in Japan. Aims: The aims of this study were to evaluate the immune status against MMR and the effects of vaccination against MMR in adult patients who received allo‐HCT. Methods: A total of 143 consecutive patients who had survived at least 2 years after allo‐HCT were included in this study. Immunoglobulin G (IgG) antibody titers against MMR were measured by enzyme immunoassay (EIA) using patient plasma. Plasma samples were routinely collected and cryopreserved in −80°C freezer until use. IgG index values of equal to or greater than 4 for measles, mumps, and rubella were considered positive. All statistical analyses were performed with EZR. This study was approved by the institutional review boards of Jichi Medical University. Written informed consent was obtained from all patients in accordance with the Declaration of Helsinki. Results: A total of 139, 61, and 121 of 143 patients were seropositive to measles, mumps, and rubella before allo‐HCT, respectively. The probabilities of being seropositive at 2 years after allo‐HCT in patients who were seropositive before allo‐HCT, were 61.7% (53.1%>69.3%) for measles, 41.0% (28.6%>52.9%) for mumps, and 51.7% (42.4%>60.2%) for rubella, respectively. To predict the loss of immunity against MMR at 2 years after allo‐HCT, we defined the following cut off values of IgG index: 18.2 for measles, 5.3 for mumps and 13.1 for rubella using the receiver‐operating characteristics curve. The lower IgG groups significantly experienced loss of being seropositive at 2 years (41% vs 83% for measles, p < 0.0001; 13% vs 60% for mumps, p = 0.00012; and 19% vs 73% for rubella, p < 0.0001). In a multivariate analysis, only the use of in vivo T‐cell depletion was associated with the preservation of seropositivity (hazard ratio (HR), 0.22 (0.05–0.95), p = 0.043 for measles and HR 0.38 (0.13–1.14), p = 0.084 for rubella). Two patients, who became seronegative for mumps after allo‐HCT, developed mumps infection during follow‐up. Otherwise, there were no documented MMR infections. After loss of being immune to MMR, 10, 5, and 11 patients received vaccination once against measles, mumps, and rubella, respectively. After vaccination, 8 (80%), 2 (40%), and 7 (72%) patients became seropositive to measles, mumps, and rubella, respectively. Summary/Conclusion: This study showed that many adult patients lost immunity to MMR after allo‐HCT. The vaccinations against MMR were effective, but additional vaccinations are necessary to increase immunity levels for patients who could not get sufficient immunity against MMR.