Live (vaccines) from New York

An ISCT Stem Cell Engineering Committee Position Statement on Immune Reconstitution: the importance of predictable and modifiable milestones of immune reconstitution to transplant outcomes

Allogeneic stem cell transplantation is a potentially curative therapy for some malignant and non-malignant disease. There have been substantial advances since the approaches first introduced in the 1970s, and the development of approaches to transplant with HLA incompatible or alternative donors has improved access to transplant for those without a fully matched donor. However, success is still limited by morbidity and mortality from toxicity and imperfect disease control. Here we review our emerging understanding of how reconstitution of effective immunity after allogeneic transplant can protect from these events and improve outcomes. We provide perspective on milestones of immune reconstitution that are easily measured and modifiable.

Vaccination of the Stem Cell Transplant Recipient and the Hematologic Malignancy Patient

Patients with hematologic malignancy or those who undergo hematopoietic stem cell transplantation experience variable degrees of immunosuppression, dependent on underlying disease, therapy received, time since transplant, and complications, such as graft-versus-host disease. Vaccination is an important strategy to mitigate onset and severity of certain vaccine-preventable illnesses, such as influenza, pneumococcal disease, or varicella zoster infection, among others. This article highlights vaccines that should and should not be used in this patient population and includes general guidelines for timing of vaccination administration and special considerations in the context of newer therapies, recent vaccine developments, travel, and considerations for household contacts.

Long-Term Follow-Up of Antibody Titers Against Measles, Mumps, and Rubella in Recipients of Allogenic Hematopoietic Cell Transplantation

Outbreaks of viral infections, such as measles, are regularly observed and pose a serious threat to recipients of allogeneic hematopoietic cell transplantation (HCT). The questions of how long cellular and humoral protective host immunity persists, and whether donor immunity can be transferred has not been clarified. Here we present a retrospective analysis of humoral immunity-serial antibody titers against measles, mumps, and rubella-in 331 patients who underwent allogeneic HCT at our single center between 2002 and 2015. Associations between the loss of protective antibody levels and clinical patient characteristics and transplantation parameters were examined. In general, antibody protection against measles persisted longer, with 72% of patients maintaining sufficient titers at 5 years post-HCT even without revaccination, while at that time only 65% and 50% of patients had protective immunity against rubella and mumps, respectively. The great majority of donors were seropositive for all 3 viruses; however, it appeared that donor humoral immunity could not be transferred and had no impact on post-HCT serostatus. Rather, the most relevant factor for persistent protective antibody titers against measles and rubella was whether patients were born before the introduction of the respective vaccine and thus were immunized by the wild-type disease-inducing virus instead of the vaccine. Moreover, the presence of moderate and severe chronic graft-versus-host disease (GVHD) was associated with more rapid loss of immune protection. In contrast, underlying disease, intensity of the conditioning regimen, use of antithymocyte globulin, age, and graft source had no influence on antibody titers. Overall, our findings suggest that the majority of antibodies against measles, mumps, and rubella originate from residual host cells, whereas donor immune status appears to have no influence on antibody protection post-HCT.

Optimal approach to assessing T-cell function in haematopoietic cell transplant recipients

Standardised approaches to functional immune assessment after haematopoietic cell transplantation (HCT) are lacking. A 12-year-old girl with relapsed acute myelogenous leukaemia, 2 years post-unrelated HCT, underwent immunological evaluation prior to receiving live vaccinations. Assessment of standard immune parameters and T-cell proliferation to phytohaemagglutinin was reassuring. She was given Varicella vaccination based on usual post-transplant protocols but was hospitalised 10 days later with localised Varicella infection (vaccine strain). Following recovery, she underwent further assessment that showed reduced T-cell proliferation to an anti-CD3 stimulation panel (anti-CD3 alone, soluble anti-CD3⁺ anti-CD28 and soluble anti-CD3⁺ plus exogenous IL-2). On reassessment, 7 months later, T-cell responses to anti-CD3 stimulation were normal and she was revaccinated without further incident. Measurement of T-cell proliferation to anti-CD3 stimulants likely yields more useful information about global T-cell function and should be strongly considered prior to live vaccine administration post-allogeneic haematopoietic transplant.

Cytomegalovirus Infection after CD34(+)-Selected Hematopoietic Cell Transplantation

The effectiveness of preemptive treatment (PET) for cytomegalovirus (CMV) in recipients of ex vivo T cell-depleted (TCD) hematopoietic cell transplantation (HCT) by CD34(+) selection is not well defined. We analyzed 213 adults who received TCD-HCT at our institution from June 2010 through May 2014. Patients were monitored by a CMV quantitative PCR assay if recipient (R) or donor (D) were CMV seropositive. CMV viremia occurred early (median, 27 days after HCT) in 91 of 213 (42.7%) patients for a 180-day cumulative incidence of 84.5%, 61.8%, and 0 for R+/D+, R+/D-, and R-/D+ patients, respectively. CMV disease occurred in 5% of patients. In Cox regression analysis, R+/D+ status was associated with increased risk for CMV viremia compared with R+/D- (hazard ratio [HR], 1.79, 95% confidence interval [CI], 1.16 to 2.76, P = .01), whereas matched unrelated donor allograft was associated with decreased risk (HR, .62; 95% CI, .39 to .97, P = .04). Of 91 patients with CMV viremia, 52 (57%) had persistent viremia (>28 days duration). Time lag from detection of CMV viremia to PET was associated with incremental risk for persistent viremia (HR, 1.09; 95% CI, 1.01 to 1.18; P = .03). Overall, 166 of 213 (77.9%) patients were alive 1 year after HCT, with no difference between patients with and without CMV viremia or among the different CMV serostatus pairs (P = not significant). CMV viremia occurred in 70% of R + TCD-HCT. Delay in PET initiation was associated with persistent viremia. With PET, CMV R/D serostatus did not adversely impact survival in TCD-HCT on 1-year survival in the present cohort.

Pretransplant vaccinations in allogeneic stem cell transplantation donors and recipients: an often-missed opportunity for immunoprotection?

Immune deficiency following hematopoietic cell transplantation predisposes the patient to potentially deadly infections. Vaccinations can improve immunity and thus reduce the morbidity and mortality associated with these infections. Over the years different sets of guidelines have been published the most recent by the Infectious Diseases Society of American (IDSA). There is limited evidence that vaccination of donors and/or recipients before transplantation may improve immunity. However, despite the possibility of augmented immunity, there remain logistical, ethical and medical concerns about such a vaccination strategy.

Autologous hematopoietic cell transplantation: an update for clinicians

High-dose chemotherapy followed by transplantation of autologous hematopoietic progenitor cells has a proven track record of safety and efficacy in hematological malignancies and select solid tumors. The near-universal use of peripheral blood stem cells as source for autografts, routine growth factor support, and antimicrobial prophylaxis post transplantation has improved the safety of this procedure. However, the advent of highly active novel therapies in the last few years warrants reappraisal of the role of autologous transplantation in the therapeutic armamentarium of malignant disorder. This review summarizes the current role of autologous transplantation for hematological malignancies, discusses modern standards for patient selection, and highlights long-term care issues of transplant survivors from an internist's perspective. Role of tumor purging in autologous transplantation, novel transplant conditioning regimens, and post-transplant therapies to prevent disease relapse are reviewed.