Informe del Taller Ibérico de Histocompatibilidad 2013. Componente de análisis de situación de procedimiento de pruebas cruzadas en guardias de trasplante de órganos / Report of the 2013 Iberian Histocompatibility Workshop of 2013. Component analysis of the proceedings of cross-matching procedures in emergency organ transplantation

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Patient with double bence jones proteinuria after hematopoietic cell transplantation.

About two thirds of patients with multiple myeloma and M-component in serum also have light chains in urine. However, the simultaneous presence of 2 Bence Jones proteins of different immunologic types in the same patient is rare. We describe the case of a 58-year-old woman with multiple myeloma, having 2 monoclonal light chains of both types (kappa and lambda) and an immunoglobulin G-lambda monoclonal protein in urine. The quantitative determination of light chains in urine was carried out using nephelometry, and Bence Jones proteinuria was confirmed by agarose gel immunofixation. To the best of our knowledge, this is the first reported case of double Bence Jones proteinuria after hematopoietic cell transplantation.

Cross-reactivity between swine leukocyte antigen and human anti-HLA-specific antibodies in sensitized patients awaiting renal transplantation.

Xenotransplantation is increasingly viewed as a promising way to alleviate the problem of patients who have alloreactive lymphocytotoxic antibodies and therefore tend to accumulate on the waiting list for renal transplantation. One barrier to xenotransplantation in these patients could be the hyperacute or acute vascular rejection as a result of preexisting anti-HLA antibodies that recognize swine leukocyte antigens. The cross-reactivity of sera from 98 patients with pig lymphocytes was studied by flow cytometry. After absorption of xenoreactive natural antibodies (XNA), isotype, class, and antibody specificity causing a positive cross-match (XM) were determined. For nonsensitized patients, all of the antibody binding to pig lymphocytes was due to XNA, which were removed by pig red blood cells absorption. In contrast, in sensitized patients, after removal of XNA, pig lymphocyte XM remained positive. There was no correlation between antibody binding to pig lymphocytes and Ig isotype (IgG or IgM) or HLA class-specific antibodies. For testing evidence that class II-specific antibodies were responsible for antibody binding to pig lymphocytes, HLA class I-specific antibodies were absorbed with pooled human platelets. It was confirmed that HLA class II-specific antibodies were responsible for the positive pig XM, but the strength of the positive XM was weaker than the strength caused by HLA class I-specific antibodies. Sera with multiple specificities (plurispecific sera) displayed a greater frequency of cross-reactivity with swine leukocyte antigens (P < 0.05). Seven of 11 highly immunized patients without cross-reactivity IgG with porcine lymphocytes showed positive XM before an IgM was used. The results demonstrate the cross-reactive nature of HLA antibodies and therefore point out the need to perform a prospective XM after absorption of XNA in presensitized individuals.

Treatment of monomorphic B-cell lymphoma with rituximab after liver transplantation in a child.

Rituximab, a monoclonal antibody directed against the B-cell specific CD20 antigen has been used with success in post-transplant lymphoproliferative disorder (PTLD) of B-cell phenotype. However, the use of such drug in children with liver transplantation and PTLD is very limited. We report a 2-yr-old liver transplant recipient with monomorphic non-Hodgkin lymphoma of B-cell origin. The lymphoma did not respond to immunosuppression withdrawal, with a subsequent allograft rejection. Despite resumption of immunosuppression and rejection treatment, the lymphoma was successfully treated with rituximab.