Human Leukocyte Antigen Homozygosity Contributes to Sensitization in Kidney Transplant Candidates

Background: Homozygosity for human leukocyte antigens (HLA) has been associated with adverse outcomes after viral infection as well as pregnancy-induced HLA sensitization. We sought to assess the relationship between HLA locus homozygosity and the level of HLA antibody sensitization. Methods: We measured sensitization using the calculated panel reactive antibody (CPRA) value for a large cohort of 147,461 patients added to the US OPTN/UNOS kidney transplant waitlist between December 2014 and December 2019. We used multinomial logistic modeling to compare 62,510 sensitized patients to 84,955 unsensitized controls. Results: We found that the number of homozygous HLA loci was strongly associated with the level of sensitization. Within highly- or extremely-sensitized candidates, women displayed a higher relative abundance of HLA homozygosity at multiple HLA loci as compared to men, with attenuation of this effect in Black candidates. In multinomial logistic modeling, the number of homozygous HLA loci was an independent predictor of sensitization and interacted with female sex but not with other factors associated with sensitization. Conclusions: This study shows that HLA homozygosity is an innate genetic factor that contributes to HLA sensitization, and enhances the effect of pregnancy-related sensitization.

Liver Transplant Imaging prior to and during the COVID-19 Pandemic

Background. The suspension of the surgical activity, the burden of the infection in immunosuppressed patients, and the comorbidities underlying end-stage organ disease have impacted transplant programs significantly, even life-saving procedures, such as liver transplantation. Methods. A review of the literature was conducted to explore the challenges faced by transplant programs and the adopted strategies to overcome them, with a focus on indications for imaging in liver transplant candidates. Results. Liver transplantation relies on an appropriate imaging method for its success. During the Coronavirus Disease 2019 (COVID-19) pandemic, chest CT showed an additional value to detect early signs of SARS-CoV-2 infection and other screening modalities are less accurate than radiology. Conclusion. There is an emerging recognition of the chest CT value to recommend its use and help COVID-19 detection in patients. This examination appears highly sensitive for liver transplant candidates and recipients, who otherwise would have not undergone it, particularly when asymptomatic.

Helicobacter pylori eradication in renal transplant candidates

Introduction: Treatment for Helicobacter pylori (H. pylori) infection is recommended in transplant candidates due to the association between this infection and gastrointestinal disorders, which could significantly increase morbidity after renal transplantation with the use of immunosuppression. The objective of this study was to analyze the rate of eradication of H. pylori after antimicrobial treatment in chronic kidney disease patients who are candidates for kidney transplantation. Methods: A multicenter prospective cohort study was conducted. All adult chronic kidney disease patients seen at our institution were included. In the pre-transplantation evaluation, 83 patients underwent an upper gastrointestinal endoscopy with 2 diagnostic methods to detect H. pylori: histology and the rapid urease test. In total, 33 patients with H. pylori infection received treatment with 20 mg omeprazole, 500 mg amoxicillin, and 500 mg clarithromycin once daily for 14 days. Another upper gastrointestinal endoscopy was performed 8 to 12 weeks after the end of treatment to check for healing. Results: The study showed a prevalence of H. pylori in 51 (61.4%) patients. Histology was positive in 50 (98%) patients and the rapid urease test was positive in 31 (60.8%). The infection eradication rate was 48.5% (16 patients). Conclusions: There was a high prevalence rate of H. pylori and a low eradication rate after the long-term antimicrobial triple scheme used. The association of the rapid urease test with gastric mucosa histology did not increase the detection rate of H. pylori.

Tocilizumab Trough Levels Variability in Kidney-Transplant Candidates Undergoing Desensitization

The presence of anti-HLA antibodies is an increasing challenge in kidney transplantation. Tocilizumab (TCZ), a monoclonal antibody targeting the interleukin-6 receptor (IL-6R), has been proposed to complement conventional desensitization therapy. We aimed to describe TCZ plasma trough concentrations and their variability and to investigate the link between TCZ concentration and the evolution of anti-HLA antibodies. Sensitized kidney-transplant candidates treated monthly with TCZ (8 mg/kg) for desensitization were retrospectively included. TCZ concentrations were determined by liquid chromatography-tandem mass spectrometry. Seventy-four TCZ concentrations from 10 patients were analyzed. The TCZ trough concentration ranged from <1.0 to 52.5 mg·L−1, with a median of 25.6 mg·L−1 [25th–75th percentiles: 13.2–35.3 mg·L−1). The inter- and intra-individual coefficients of variation were 55.0% and 33.0%, respectively. The TCZ trough concentration was not related to IL-6 (rho = −0.46, p = 0.792), soluble IL-6R (rho = −0.81, p = 0.65) concentrations or reduction of anti-HLA antibodies (mixed-effects model adjusting, effect of TCZ trough concentration: rho = −0.004, p = 0.26). The individual median TCZ concentration tended to be associated with the number of antibodies, with an initial MFI > 3000 that dropped to <3000 after TCZ treatment (rho = 0.397, p = 0.083). TCZ trough concentrations in kidney-transplant candidates treated for desensitization were highly variable. Further studies on larger cohorts are needed to study the possible link between TCZ concentrations and the reduction of anti-HLA antibodies.

Differential Diagnosis of Abdominal Tuberculosis in the Adult—Literature Review

Tuberculosis (TB) is a public health issue that affects mostly, but not exclusively, developing countries. Abdominal TB is difficult to detect at first, with the incidence ranging from 10% to 30% of individuals with lung TB. Symptoms are non-specific, examinations can be misleading, and biomarkers commonly linked with other diseases can also make appropriate diagnosis difficult. As a background for this literature review, the method used was to look into the main characteristics and features of abdominal tuberculosis that could help with differentiation on the PubMed, Science Direct, and Academic Oxford Journals databases. The results were grouped into three categories: A. general features (the five forms of abdominal tuberculosis: wet and dry peritonitis, lymphadenopathy, lesions at the level of the cavitary organs, lesions at the level of the solid organs), B. different intra-abdominal organs and patterns of involvement (oesophageal, gastro-duodenal, jejunal, ileal, colorectal, hepatosplenic, and pancreatic TB with calcified lymphadenopathy, also with description of extraperitoneal forms), and C. special challenges of the differential diagnosis in abdominal TB (such as diagnostic overlap, the disease in transplant candidates and transplant recipients, and zoonotic TB). The study concluded that, particularly in endemic countries, any disease manifesting with peritonitis, lymphadenopathy, or lesions at the level of the intestines or solid organs should have workups and protocols applied that can confirm/dismiss the suspicion of abdominal tuberculosis.