PURPOSE: Hematopoietic cell transplantation (HCT) recipients are vulnerable to invasive infection by Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (Sp). This study was performed to evaluate immune responses after Hib and Sp vaccination in Korean pediatric HCT recipients. METHODS: Patients were prospectively enrolled at Samsung Medical Center during 2009-2011. ELISA tests to detect anti-PRP IgG antibody and antibodies to Sp serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F were performed at the Center for Vaccine Evaluation and Study, Ewha Medical Research Institute. RESULTS: Ten patients (two allogeneic, eight autologous recipients) with median age 5.4 years (range 2.7-12.2 years) were enrolled. Before Hib vaccination, 60% of patients' anti-PRP IgG titers were below 0.15 microg/mL. After vaccination, 100% of patients' anti-PRP IgG titers increased above 0.15 microg/mL (cut-off value for detection) and 1.0 microg/mL (cut-off value for seroprotection). For pneumococcus, in 2-5 year-old patients, pre-vaccination geometric mean concentrations (GMCs) of IgG for six serotypes (4, 6B, 9V, 14, 18C, and 23F) were below 0.35 microg/mL and at 5 months post-vaccination GMCs of IgG for all seven serotypes increased to above 0.35 microg/mL. In patients older than 5 years, pre-vaccination GMCs of IgG for four serotypes (4, 9V, 14, and 23F) were below 0.35 microg/mL and at 3 months post-vaccination GMCs of IgG for all seven serotypes increased to above 0.35 microg/mL. CONCLUSION: Most HCT recipients had low or no protective antibodies to Hib and Sp before vaccination, but showed good immune responses to protective levels after vaccination.
Academies and Institutes ; Antibodies ; Antibody Formation* ; Cell Transplantation* ; Enzyme-Linked Immunosorbent Assay ; Haemophilus influenzae type b* ; Humans ; Immunoglobulin G ; Prospective Studies ; Streptococcus pneumoniae* ; Transplants* ; Vaccination*

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematologic disorder characterized by uncontrolled terminal complement activation. Eculizumab, a monoclonal antibody C5 inhibitor was introduced in Korea in 2009 and has been the standard treatment option for PNH. Methods: This study assessed the long-term efficacy/safety of eculizumab in PNH using real-world data from the Korean Health Insurance Review and Assessment Service. Eighty patients who initiated eculizumab from 2009–2020 were enrolled. Results: At eculizumab initiation, the median age was 51.5 years, lactate dehydrogenase (LDH) 6.8 × upper limit of normal, and granulocyte clone size 93.0%. All patients had at least one PNH-related complication before eculizumab initiation, including renal failure (n = 36), smooth muscle spasm (n = 24), thromboembolism (n = 20), and pulmonary hypertension (n = 15). The median (range) duration of eculizumab treatment was 52.7 (1.0, 127.3) months (338.6 total treated patient-years). Despite high disease activity in the study population before treatment initiation, overall survival was 96.2% and LDH levels were stabilized in most patients during treatment. PNH-related complications at treatment initiation were resolved in 44.4% of patients with renal failure, 95.8% with smooth muscle spasm, 70.0% with thromboembolism, and 26.7% with pulmonary hypertension. Extravascular hemolysis occurred in 28.8% of patients (n = 23; 0.09 per patient-year) and breakthrough hemolysis in 18.8% (n = 15; 0.06 per patient-year). No treatment discontinuation cases related to eculizumab were observed. Conclusion These data provided evidence for the long-term efficacy and safety of eculizumab in Korean PNH patients with high disease burdens.