Antibody waning after immunosuppressive chemotherapy and immunomodulators, re-immunization considerations in pediatric patients with malignancy and chronic immune thrombocytopenic purpura

Abstract

Introduction Immunosuppressive chemotherapy increase the risk of vaccine-preventable infectious diseases in children; nevertheless, chemotherapy may result in delay or miss updated immunization schedules. The predictable antibody waning after incomplete primary immunization series may be intensified at the end of chemotherapy. This study aimed to investigate post-chemotherapy vaccine immunity waning at the end of immunosuppressive therapy in children with malignancy and hematologic disorders. Materials and methods Children with malignancies and hematologic disorders including chronic immune thrombocytopenic purpura (ITP) younger than 18 years old were enrolled from September 2015 to August 2019. Eligible patients who completed their treatment protocol for at least 6 months were recruited. The patient information, including sex, age at the date of diagnosis, number of chemotherapy sessions, underlying disease, and vaccination history, was taken by chart review using predefined questionnaires. The patient’s blood samples were obtained, and serum IgG antibody titer checked against diphtheria, tetanus, hepatitis B virus (HBV), mumps, measles, and rubella (MMR) were measured by enzyme-linked immunosorbent assay (ELISA). Results 110 children receiving immunosuppressive chemotherapy were recruited. Forty-four (40%) of the children tested were girls and 66 (60%) were boys. The mean age of patients was 5.5 years with a range of 2 to 13 years. Of 110 studied children, 27.3% were seronegative for all antibodies. On average, patients undergo 19 episodes of chemotherapy. The mean chemotherapy sessions were significantly greater in children who were seronegative for all tested antibodies (mean: 36.2, 95% CI 33.16 to 39.24, p-value < 0.001). No statistically significant differences were observed regarding the patient’s sex and age between the seropositive and seronegative groups (p-value 0.513 and 0.060, respectively). Based on Poisson regression model analysis, the female gender was associated with 37% lower odds of seronegativity (incidence rate ratio (IIR): 0.63; [95% conf. interval: 0.39 to 1.01, p-value: 0.55]), while chemotherapy sessions 30 or more was associated with significant odds of seronegativity for all tested vaccines (IIR: 25.41; [95% conf. interval: 6.42 to 100.57, p-value < 0.001]). Conclusion Our results reemphasized planned catchup immunization in children undergoing immunosuppressive chemotherapy for malignancy, especially against tetanus, diphtheria, and hepatitis B at least 6 months after the end of chemotherapy sessions.

A Mannose-Modified Lipid Calcium Phosphate Nanoparticle Vaccine Increased the Anti-Tumor Immune Response by Modulating the Tumor Microenvironment

“…Through in-depth investigation of its mechanism of action, we found that the vaccine can effectively regulate the tumor microenvironment and enhance the anti-tumor immune response of the body. Studies [251][252][253] have shown that mannose-modified nanoparticles can promote uptake and endocytosis of tumor cells through specific targeting, thereby improving the efficiency of antigen delivery and activating the activity of tumor-associated antigen-specific T cells. In addition, the vaccine can also induce immune cells in the tumor microenvironment, such as plasma cells and dendritic cells, to release proinflammatory factors, and inhibit the function of immunosuppressive cells, thereby promoting the activation and expansion of T cells, enhancing the killing ability of cytotoxic T lymphocytes, and finally realizing the effective elimination of tumors.…”

Vaccinations in children with hematologic malignancies and those receiving hematopoietic stem cell transplants or cellular therapies

“…[12][13][14] Protective antibodies may drop regardless of a patient's vaccination status before chemotherapy or donor or recipient vaccination status before transplantation. 13,[15][16][17][18][19] Fortunately, revaccination or resumption of indicated vaccinations following completion of cancer therapy can produce protective immunity in these children, even in patients with some ongoing immunosuppression. [19][20][21]…”