Solutions to Avoid False Positives for Rituximab in Pre-Transplant Crossmatches.

Rituximab (anti-CD20) is commonly used as immunotherapy against B cells, in the context of pre-transplant crossmatches, where the presence of rituximab in the tested sera with donor cells can alter their results both by flow cytometry (FCXM) as complement-dependent cytotoxicity (CDCXM) giving rise to false positives. In the present study, we tested the use of an anti-rituximab monoclonal antibody (10C5, Abnova) as a method to avoid false positives in FCXM and CDCXM. We used the serum from ten patients who received therapy with rituximab, and the cells were incubated with sera treated or untreated with the 10C5 clone. In previous studies, attempts have been made to control these false positives through the use of pronase, although in these cases the alteration of Human Leukocyte Antigen (HLA) molecules has been found to be a limitation. As an alternative, we performed an assay to exclude false positives by a pre-incubation with anti-rituximab antibody (10C5) in 1:5 proportion avoiding the misinterpretation of crossmatches, particularly in patients with specific donor antibodies (DSA) without affecting the HLA molecules.

Possible role of HLA class-I genotype in SARS-CoV-2 infection and progression: A pilot study in a cohort of Covid-19 Spanish patients.

Human Leukocyte Antigen (HLA) includes a large set of genes with important actions in immune response against viral infection. Numerous studies have revealed the existence of significant associations between certain HLA alleles and the susceptibility and prognosis of different infectious diseases. In this pilot study we analyse the binding affinity between 66 class I HLA alleles and SARS-CoV-2 viral peptides, and its association with the severity of the disease. A total of 45 Spanish patients with mild, moderate and severe SARS-CoV-2 infection were typed for HLA class I; after that, we analysed if an in silico model of HLA I-viral peptide binding affinity and classical HLA supertypes could be correlated to the severity of the disease. Our results suggest that patients with mild disease present Class I HLA molecules with a higher theoretical capacity for binding SARS-Cov-2 peptides and showed greater heterozygosity when comparing them with moderate and severe groups. In this regard, identifying HLA-SARS-CoV-2 peptides binding differences between individuals would help to clarify the heterogeneity of clinical responses to the disease and will also be useful to guide a personalized treatment according to its particular risk.

El descenso del número de linfocitos B de memoria en pacientes con inmunodeficiencia variable común está asociado a una apoptosis aumentada de esta población celular. Desarrollo de un método nuevo para la detección de la apoptosis en muestras de sangre completa / No disponible

La inmunodeficiencia variable común(IDVC) es una enfermedad heterogénea caracterizada por una disminución de los valores absolutos de los linfocitos B de memoria en la sangreperiférica.Apesardequeestadisminuciónsehaatribuidopreviamenteaunposibledefectoen el desarrollo del centro germinal, las causas permanecen en gran medida desconocidas. Por otro lado, la apoptosis (,,) (AU)

Common Variable Immunodeficiency (CVID) is a heterogeneous disease characterized by low memory B cell counts in peripheral blood (PB). Although previous reports have attributedmemoryCD27+Bcelldecrease to a possible defective germinal centre development, the cause of this defect remains basically unknown. On the other hand, increased apoptosis has been implicated in the pathogenesis of several diseases, and could be another factor that contributes (..)(AU)