Leandra Bitterfeld

All Publications

• Tacrolimus variability and medication adherence pre- and post-conversion from immediate-release to extended-release tacrolimus in pediatric solid organ transplant. Pediatric transplantation Bitterfeld, L., Jackson, R. L., Sanchez-Garcia, J., Bucher, B., Brewer, A., Heyrend, C. 2026; 30 (6): e70381

  Abstract

  Adolescents receiving solid organ transplants (SOT) are at increased risk for rejection and graft loss, driven by suboptimal immunosuppressive medication adherence. This study evaluated the effect of conversion from immediate-release tacrolimus (IR-Tac) to extended-release tacrolimus (LCPT) on medication adherence in pediatric SOT recipients.We conducted a retrospective, observational single-center study of heart, liver, and kidney transplant recipients who converted from IR-Tac to LCPT. Medication adherence was measured as tacrolimus standard deviation (tac-SD), with tac-SD > 2 considered the threshold for poor adherence, and self-reported adherence during the one year before and after conversion.Fifty-four pediatric SOT recipients were included, with a median age of 9 years at transplant and 14.4 years at conversion from IR-Tac to LCPT. Among the entire cohort, overall tac-SD did not differ before and after conversion. Among children with high baseline variability (tac-SD > 2), tac-SD significantly decreased from a median of 3.0 to 2.7 (p = 0.014), whereas children with low baseline variability (tac-SD < 2) experienced a significant increase in tac-SD from 1.3 to 2.2 (p < 0.001). The proportion of children reporting missed doses more than once a week decreased from 13 (24%) to 7 (13%; p = 0.07). There was no change in tac-SD between children who were and were not converted to LCPT for an adherence concern.Tac-SD decreased after conversion from IR-Tac to LCPT among those with high baseline variability but increased among those with low baseline variability; there were no significant changes in subjective adherence measures. The effectiveness of conversion from IR-Tac to LCPT for adherence is unclear.

  View details for DOI 10.1111/petr.70381

  View details for PubMedID 42334001

• Postvaccination Immunogenicity Among Pediatric Solid Organ Transplant Recipients. JAMA pediatrics Feldman, A. G., Beaty, B. L., Ferrolino, J. A., Maron, G., Ali, S. A., Bitterfeld, L., Blatt, A., Boulware, M. A., Campbell, K. M., Carr, E., Cetin, B., Chapman, S., Chang, Y. C., Cunningham, R., Dallas, R. H., Dantuluri, K. L., Domenick, B. N., Ebel, N. H., Elisofon, S., Fawaz, R., Foca, M., Gans, H. A., Gopalareddy, V. V., Gupta, N. A., Harmann, K., Hollenbeck, J., Huppler, A. R., Jaramillo, C., Kasi, N., Kerkar, N., Lerret, S., Lobritto, S. J., Lopez, M. J., Mavis, A., Mehra, S., Mohandas, S., Munoz, F. M., Mysore, K. R., Ovchinsky, N., Perkins, K., Postma, S., Pratscher, L., Rand, E. B., Rowe, R. K., Ruderfer, D., Schultz, D., Sear, K., Sell, M. L., Sharma, T. S., Stoll, J., Turner, J., Valencia Deray, K. G., Villarin, D., Weaver, C., Wood, P., Woodford-Berry, O., Yanni, G., Danziger-Isakov, L. A. 2025

  View details for DOI 10.1001/jamapediatrics.2024.6778

  View details for PubMedID 39992645

• Safety and Immunogenicity of Live Viral Vaccines in a Multicenter Cohort of Pediatric Transplant Recipients. JAMA network open Feldman, A. G., Beaty, B. L., Ferrolino, J. A., Maron, G., Weidner, H. K., Ali, S. A., Bitterfeld, L., Boulware, M. A., Campbell, K. M., Carr, E., Chapman, S., Chang, Y., Cunningham, R., Dallas, R. H., Dantuluri, K. L., Domenick, B. N., Ebel, N. H., Elisofon, S., Fawaz, R., Foca, M., Gans, H. A., Gopalareddy, V. V., Gu, C., Gupta, N. A., Harmann, K., Hollenbeck, J., Huppler, A. R., Jaramillo, C., Kasi, N., Kerkar, N., Lerret, S., Lobritto, S. J., Lopez, M. J., Marini, E., Mavis, A., Mehra, S., Moats, L., Mohandas, S., Munoz, F. M., Mysore, K. R., Onsan, C., Ovchinsky, N., Perkins, K., Postma, S., Pratscher, L., Rand, E. B., Rowe, R. K., Schultz, D., Sear, K., Sell, M. L., Sharma, T., Stoll, J., Vang, M., Villarin, D., Weaver, C., Wood, P., Woodford-Berry, O., Yanni, G., Danziger-Isakov, L. A. 2023; 6 (10): e2337602

  Abstract

  Importance: Live vaccines (measles-mumps-rubella [MMR] and varicella-zoster virus [VZV]) have not been recommended after solid organ transplant due to concern for inciting vaccine strain infection in an immunocompromised host. However, the rates of measles, mumps, and varicella are rising nationally and internationally, leaving susceptible immunocompromised children at risk for life-threating conditions.Objective: To determine the safety and immunogenicity of live vaccines in pediatric liver and kidney transplant recipients.Design, Setting, and Participants: This cohort study included select pediatric liver and kidney transplant recipients who had not completed their primary MMR and VZV vaccine series and/or who displayed nonprotective serum antibody levels at enrollment between January 1, 2002, and February 28, 2023. Eligibility for live vaccine was determined by individual US pediatric solid organ transplant center protocols.Exposures: Exposure was defined as receipt of a posttransplant live vaccine. Transplant recipients received 1 to 3 doses of MMR vaccine and/or 1 to 3 doses of VZV vaccine.Main Outcome and Measure: Safety data were collected following each vaccination, and antibody levels were obtained at 0 to 3 months and 1 year following vaccination. Comparisons were performed using Mann-Whitney U test, and factors associated with development of postvaccination protective antibodies were explored using univariate analysis.Results: The cohort included 281 children (270 [96%] liver, 9 [3%] kidney, 2 [1%] liver-kidney recipients) from 18 centers. The median time from transplant to enrollment was 6.3 years (IQR, 3.4-11.1 years). The median age at first posttransplant vaccine was 8.9 years (IQR, 4.7-13.8 years). A total of 202 of 275 (73%) children were receiving low-level monotherapy immunosuppression at the time of vaccination. The majority of children developed protective antibodies following vaccination (107 of 149 [72%] varicella, 130 of 152 [86%] measles, 100 of 120 [83%] mumps, and 124 of 125 [99%] rubella). One year post vaccination, the majority of children who initially mounted protective antibodies maintained this protection (34 of 44 [77%] varicella, 45 of 49 [92%] measles, 35 of 42 [83%] mumps, 51 of 54 [94%] rubella). Five children developed clinical varicella, all of which resolved within 1 week. There were no cases of measles or rubella and no episodes of graft rejection within 1 month of vaccination. There was no association between antibody response and immunosuppression level at the time of vaccination.Conclusions and Relevance: The findings suggest that live vaccinations may be safe and immunogenic after solid organ transplant in select pediatric recipients and can offer protection against circulating measles, mumps, and varicella.

  View details for DOI 10.1001/jamanetworkopen.2023.37602

  View details for PubMedID 37824141