Clinical characteristics of unvaccinated or incompletely vaccinated children with neurological manifestations due to SARS-CoV-2 Omicron infection.

Omicron generally causes milder disease than previous strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), especially in fully vaccinated individuals. However, incompletely vaccinated children may develop Omicron-related complications such as those affecting the central nervous system. To characterize the spectrum of clinical manifestations of neuro-COVID and to identify potential biomarkers associated with clinical outcomes, we recruited 15 children hospitalized for Omicron-related neurological manifestations in three hospitals in Hong Kong (9 boys and 6 girls aged 1-13 years). All were unvaccinated or incompletely vaccinated. Fourteen (93.3%) were admitted for convulsion, including benign febrile seizure (n = 7), complex febrile seizure (n = 2), seizure with fever (n = 3), and recurrent breakthrough seizure (n = 2), and the remaining nonconvulsive patient developed encephalopathic state with impaired consciousness. None of the seven children with benign febrile seizure and six of eight children with other neurological manifestations had residual deficits at 9-month follow-up. SARS-CoV-2 RNA was undetectable in the cerebrospinal fluid (CSF) specimens of seven patients who underwent lumbar puncture. Spike-and-wave/sharp waves affecting the frontal lobes were detected in four of seven (57.1%) patients who underwent electroencephalogram. Children with Omicron-related neurological manifestations had significantly higher blood levels of IL-6 (p < 0.001) and CHI3L1 (p = 0.022) than healthy controls, and higher CSF levels of IL-6 (p = 0.002) than children with non-COVID-19-related febrile illnesses. Higher CSF-to-blood ratios of IL-8 and CHI3L1 were associated with longer length of stay, whereas higher ratios of IL-6 and IL-8 were associated with higher blood tau level. The role of CSF:blood ratio of IL-6, IL-8, and CHI3L1 as prognostic markers for neuro-COVID should be further evaluated.

HLA-B*58:01 screening to prevent allopurinol-induced severe cutaneous adverse reactions in Chinese patients with chronic kidney disease.

Human leukocyte antigen (HLA)-B*58:01 allele is a significant risk factor for allopurinol-induced severe cutaneous adverse reactions (SCARs) which is potentially fatal. In some studies, chronic kidney disease (CKD) was also implicated to compound the risk of SCARs. We aim to investigate if pre-treatment HLA-B*58:01 screening can prevent allopurinol-induced SCARs in Chinese patients with CKD and its cost-effectiveness. We prospectively recruited Chinese CKD patients who required allopurinol during 2011-2015 and performed pre-treatment HLA testing (HLA screening group). Patients tested positive for HLA-B*58:01 were refrained from allopurinol while those tested negative were prescribed allopurinol. The incidence of SCARs in the HLA screening group was compared with the historical control in previous 5 years and the cost-effectiveness of HLA testing was analyzed. In the historical control (2006-2010), 3605 patients on allopurinol were screened, 22 out of 1027 (2.14%) CKD Chinese patients newly started on allopurinol developed SCARs, including 6 SJS/TEN. In the HLA screening group, 28 out of 192 patients (14.6%) tested HLA-B*58:01 positive were advised to avoid allopurinol; 156 out of 164 HLA-B*58:01-negative patients received allopurinol and none developed SCARs. The incidence rate of SCARs was significantly lower in the HLA screening group compared with controls (0% vs 2.14% respectively, p = 0.037*). The targeted HLA screening approach was associated with lower healthcare costs compared with no HLA screening (US$ 92,430 vs US$ 281,226). Pre-treatment HLA-B*58:01 screening is cost-effective to target on patients with CKD in Chinese to prevent allopurinol-induced SCARs.

Revisit of Optimal Donor Number Estimation in the Hong Kong Bone Marrow Donor Registry.

High resolution typing of the HLA-DPB1 locus for patient who requested for hematopoietic stem cell transplantation (HSCT) workup has recently become mandatory by the National Marrow Donor Program (NMDP) in order to facilitate matching between donors and recipients for better outcomes. The likelihood of identifying HLA matched donors in Hong Kong, on top of the existing HLA-A, -B, -C, and -DRB1 loci, is revisited in this study. HLA-A, -B, -C, -DRB1 and -DPB1 genotypes of 5,266 volunteer unrelated Chinese donors from the Hong Kong Bone Marrow Donor Registry (HKBMDR), were included in this study. Matching models were employed to determine the matching probabilities for 10/10(DPB1) and 9/10(DPB1) HLA match. The matching probabilities are 20% at 10/10(DPB1) HLA match and 55% at 9/10(DPB1) match, based on the existing 130,000 donors in the HKBMDR. The likelihoods of match become 27% and 65% respectively, by increasing the registry to 250,000. However, if DPB T-cell-epitope (TCE) model is considered in the matching, the probability will increase to 46% at 10/10 DPB1 permissive mismatching. Our findings provide vital information about the future planning on the targeted recruitment size, HLA typing and search strategies of the donor registry and arose the transplant physicians' acceptability to 9/10(DBP1) or 10/10(DBP1) HLA match. Nevertheless, the marrow donor registry has planned for increasing the registry size and bringing down the age of recruited donors which will ultimately enhance patient outcome.

Risk factors and prognosis of late acute rejection in Chinese kidney transplant recipients.

AIM: Accumulating literature indicates that late acute rejection (LAR) after kidney transplantation portends an unfavourable prognosis. There are no data on the incidence of LAR in Asian subjects, or its risk factors and associated clinical outcomes. METHODS: We conducted a retrospective single-centre case-+control study to investigate the incidence, risk factors and prognosis of LAR in Chinese kidney transplant recipients. Subjects with or without LAR were matched for age, gender, era of transplantation, allograft type, and maintenance immunosuppression regimen. RESULTS: Thirty-two episodes of LAR occurred within an observation period of 12 years giving an incidence rate of 0.46 episodes per 1000 patient-years. Acute rejection within the first year after transplantation was associated with an increased risk of LAR (OR 3.59, P = 0.041). In patients receiving maintenance immunosuppression regimen with steroid, cyclosporin A (CsA) and mycophenolate or an m-TOR inhibitor, patients with LAR showed lower trough CsA levels prior to and at the time of rejection compared to Controls (86.0 ± 26.1 vs. 105.6 ± 13.3 µg/L, P = 0.049; and 75.7 ± 35.7 vs. 106.0 ± 20.5 µg/L, P = 0.032, respectively). Trough CsA level below 80 µg/L was associated with the development of LAR (OR 10.82, P = 0.032). Patients with LAR showed an inferior allograft survival (P < 0.001) while patient survival rates were similar (P = 0.122). CONCLUSIONS: Late acute rejection is uncommon in Chinese kidney transplant recipients but is associated with reduced allograft survival. Risk factors include acute rejection in the first post-transplant year and trough CsA level below 80 µg/L in patients on CsA-based maintenance immunosuppression. Minimization of immunosuppression in apparently stable kidney transplant recipients must be exercised with caution.

Lowered Immune Cell Function in Liver Recipients Recovered From Posttransplant Lymphoproliferative Disease Who Developed Graft Tolerance.

UNLABELLED: Tolerance after treatment and recovery from posttransplant lymphoproliferative disease (PTLD) have been described but little is known about the immunology. The objective of this study is to evaluate the immunity of pediatric recipients who recovered from PTLD. MATERIALS AND METHODS: Pediatric recipients who recovered from PTLD after liver transplant and twice the number of recipients who never had PTLD were recruited. Their immune statuses were measured by ImmuKnow (measurement of adenosine 5-triphospate level produced CD4+ T helper cells), and the results were divided into 3 groups, "low" (≤225 ng/mL), "moderate" (226 to 524 ng/mL), and "high" (≥525 ng/mL). The results of both groups were compared and analyzed. RESULTS: Nine PTLD recipients and 20 non-PTLD recipients were recruited. There were no significant differences in terms of sex and age between the 2 groups. The majority of PTLD recipients (88.9%) had "low" immune status responses, and none of them had "high" responses. For non-PTLD recipients, more than half (55%) had "moderate" immune status responses. The median value of adenosine 5-triphospate levels was significantly lower in the PTLD group (119 ng/mL vs 380.5 ng/mL P = 0.014), and their trough immunosuppressant level was also lower (3.8 µg/L vs 7.7 µg/L; P = 0.004). None of the patients in either group had abnormal liver enzymes (aspartate aminotransferase/alanine aminotransferase) to suggest graft rejection. CONCLUSIONS: Patients who recovered from PTLD have a lower CD4 T-cell activity compared with those who have not suffered from PTLD. Under careful monitoring, their immunosuppressant levels can be kept at low levels to prevent recurrence of PTLD.