Trends of bone mineral density and bone quality in a paediatric kidney transplant recipient: A case report.

Kidney transplant (KT) requires long-term glucocorticoid (GC) treatment against acute and/or chronic rejection. Glucocorticoid-induced osteoporosis (GIOP) is one of the major concerns in kidney transplant recipients (KTRs). Therefore, it is essential to accumulate GIOP data from paediatric KTRs to aid in their healthy growth. A serial observational study of bone strength was carried out in an 8-year-old girl with bilateral hypoplastic kidney who underwent ABO-compatible living-donor KT and GC treatment over 2 years. Bone strength was evaluated by bone mineral density (BMD) and serum bone turnover markers (BTMs), including serum alkaline phosphatase (S-ALP), serum tartrate-resistant acid phosphatase 5b (S-TRACP-5b), and serum undercarboxylated osteocalcin (S-ucOC). All the levels of BTMs and BMD from 1 M to 4 M remained lower than the levels at 0 months (0 M: baseline). After gradual reduction of GC dose (4 M-24 M), S-ALP levels increased from baseline and S-TRACP-5b levels remained lower than the baseline level, but BMD recovered to baseline and increased. The S-ucOC levels did not increase from baseline. The patient's height growth velocity SDS was +3.99 for 23 months, and no fracture occurred during this observation period. A consistent, predominantly formative state of bone, which maintained higher S-ALP levels and lower S-TRACP-5b levels compared to baseline, could contribute to increased BMD. In addition, no increase in S-ucOC levels from baseline could be associated with no deterioration of bone strength. This case suggests that measurement of BMD and, S-ALP, TRACP-5b and ucOC could be useful for evaluating the trend on bone strength in a paediatric KTR.

Lack of persisting antibody in a post-transplant patient after vaccine-strain varicella.

BACKGROUND: LAVV have historically been avoided in children after solid organ transplantation. However, it has been reported that post-transplant, children without severe immunosuppression can generate anti-varicella antibody after immunization but the duration of the response is not clear. Furthermore, the origin of the varicella virus in immunosuppressed patients who develop varicella after vaccination is often unclear. CLINICAL PROGRESS: A female child received LAVV 30 months after a living donor liver transplant at the age of 2 months. Varicella rash appeared on the trunk 16 days after vaccination and gradually spread over the body. The patient was treated with intravenous acyclovir followed by oral therapy and recovered fully. The virus detected in blisters was derived from the vaccine-type strain. Paired sera before and after the onset of varicella showed an increase in antibody titer. However, 2 years after onset, the antibody titer decreased to undetectable again. CONCLUSIONS: This was an informative case of varicella due to vaccine strain attenuated virus. Antibody levels were not maintained over many years. Although varicella was caused by the vaccine-type strain, repeated vaccinations may be necessary for post-transplant patients who develop varicella.

Glucocorticoid effects on bone strength in children with renal diseases.

AIM: Glucocorticoids (GC) are essential medicines for idiopathic steroid-sensitive nephrotic syndrome (ISSNS) and IgA nephropathy (IgAN), with good clinical results. However, they cause bone fragility. The aim of this study was to elucidate GC effects on bone strength assessed as bone mineral density (BMD) and bone quality, using bone turnover markers (BTM), in children with ISSNS or IgAN. METHODS: Eleven children with ISSNS and 13 with IgAN were included. All the patients received GC treatment according to each protocol. The BMD and BTM-serum alkaline phosphatase (S-ALP), tartrate-resistant acid phosphatase 5b (S-TRACP-5b), and undercarboxylated osteocalcin (S-ucOC)-were measured from the initiation of steroid treatment (STx) to the end of STx in both groups. RESULTS: In ISSNS, S-ALP and S-ucOC levels were decreased significantly at 1 month. BMD and S-TRACP-5b levels showed no significant change through this observation period. In IgAN, BMD and S-ALP levels were decreased significantly at 1 and 3 months, respectively, and recovered to baseline at 10 months after the initiation of GC dosage reduction. S-TRACP-5b levels were decreased significantly at 3 months and remained lower than at baseline through the observation period. In both groups, S-ucOC levels did not directly reflect bone strength. CONCLUSION: This study clarified the following three points regarding GC effects on bone strength in children with ISSNS or IgAN: first, S-ALP is a more sensitive bone quality marker than S-TRACP-5b; second, BMD loss was observed only when both S-ALP and S-TRACP-5b levels decreased, and third, S-ucOC levels do not directly reflect bone strength.

Inter- and intra-individual differences regarding SARS-CoV-2 and influenza vaccination in pediatric kidney transplant recipients: An observational study.

In kidney transplant recipients (KTRs), viral infection can lead to antibody and/or T-cell mediated rejection, resulting in kidney transplant dysfunction. Therefore, it is critical to prevent infections. However, KTRs exhibit suboptimal responses to SARS-CoV-2 and/or influenza vaccines, partly due to immunosuppressant therapy. Inter- and intra-individual differences in the biological responses to vaccines may also affect patients' antibody production ability. This study included KTRs who received an messenger RNA SARS-CoV-2 vaccine (3 doses), and an inactivated quadrivalent influenza vaccine (1 or 2 doses). We measured the patients' total antibody titers against SARS-CoV-2 spike antigen, and hemagglutination inhibition (HI) titers against influenza A/H1N1, A/H3N2, B/Yamagata, and B/Victoria. Five patients were eligible for this study. Of these 5 KTRs, two produced anti-SARS-CoV-2 spike antibody titers to a seroprotective level, and also produced HI titers against A/H1N1 to a seroprotective level. Another 2 KTRs did not produce seroprotective anti-SARS-CoV-2 antibody titers, but produced seroprotective HI titers against A/H1N1. The remaining KTR produced a seroprotective anti-SARS-CoV-2 antibody titer, but did not produce a seroprotective HI titer against A/H1N1. The 2 KTRs who did not produce seroprotective anti-SARS-CoV-2 antibody titers following vaccination, later developed COVID-19, and this infection increased their titers over the seroprotective level. This study demonstrated that inter- and intra-individual differences in biological responses to vaccines should be considered in pediatric KTRs, in addition to immunosuppressant effects. Personalized regimens, such as augmented or booster doses of vaccines, could potentially improve the vaccination efficacy against SARS-CoV-2 and influenza.