17th IHIW component "Immunogenetics of Ageing" - New NGS data.

The 'Immunogenetics of Aging' project is a component introduced in the 14th International HLA and Immunogenetics Workshop (IHIW) and developed further within subsequent workshops. The aim was to determine the relevance of immunogenetic markers, focusing on HLA, cytokine genes, and some innate immunity genes, for successful aging and an increased capacity to reach the extreme limits of life-span. Within the 17th IHIW we applied Next Generation Sequencing methods to refine further HLA associations at allele level in longevity, and to extend our knowledge to additional loci such as HLA-DQA1, HLA-DPB1 and HLA-DPA1. Analysis of relatively small number of healthy elderly and young controls from four populations showed that some HLA class I and class II alleles were significantly positively associated with healthy aging. Additionally we observed statistically significant differences in HLA allele distribution when the analysis was performed separately in elderly females and males compared to sex-matched young controls. Haplotypes, probably associated with better control of viral and malignant diseases were increased in the elderly sample. These preliminary NGS data could confirm our hypotheses that survival and longevity might be associated with selection of HLA alleles and haplotypes conferring disease resistance or susceptibility. Therefore HLA alleles and haplotypes could be informative immunogenetic markers for successful ageing.

The frequency of HLA alleles in the Romanian population.

Knowledge of human leukocyte antigen (HLA) allele frequencies is essential for bone marrow and kidney donor searches. The Romanian Caucasian population is heterogeneous and information on HLA polymorphism has not been well studied. We characterized the HLA genetic profile and allele frequencies of regional populations in Romania. HLA-A, B and DRB1 alleles were examined in 8252 individuals, belonging to the four main regions of Romania. The most common alleles found in the Romanian population are the following: HLA-A*01, A*02, A*03, A*11, A*24; HLA-B*18, B*35, B*44, B*51 and HLA-DRB1*01, DRB1*03, DRB1*07, DRB1*11, DRB1*13, DRB1*15, DRB1*16. More than half of the alleles are non-homogeneously spread in Romania. These results provide a starting point for future analyses of genetic heterogeneity in Romania.

Cytotoxic antibodies monitoring in kidney transplantation--their clinical relevance and challenges.

INTRODUCTION: The key of the successful renal transplantation is the ability to identify the best immunological match between donor and recipient considering the possibility of rejection phenomenon. The aim was to identify class I and/or class II cytotoxic antibodies in renal-transplanted patients in order to assess the immunological potential for prevention of subclinical or acute rejection episodes. PATIENTS AND METHODS: We have evaluated ninety-two patients who had kidney transplantation in 2010 in Fundeni Clinical Institute, Bucharest, Romania, concerning HLA matching and anti-HLA immunization status. For HLA genotyping were used molecular biology methods--PCR-SSP (Invitrogen, USA). For cytotoxic antibodies, the methods used were ELISA (GTI Diagnostics, USA) and Luminex (One Lambda, USA). Crossmatch tests between donor cells and recipient serum were performed by ELISA (GTI Diagnostics, USA). Rejection diagnosis was supported by renal biopsy. RESULTS: In the 20 presensitized cases, the rate of acute rejection was 30% while in the 72 unsensitized cases the rejection was 19.4%. The incidence of acute rejection was higher in anti-HLA class I presensitized patients compared with anti-HLA class II (20% and 14.3%, respectively) but there was no significant difference compared to pre-transplant unsensitized patients (19.4%). Sequential post-transplantation monitoring of anti-HLA antibodies has shown in pre-transplant sensitized patients group a constantly increasing of PRA value, while in the pre-transplant unsensitized patients group, 32% developed de novo cytotoxic antibodies. CONCLUSIONS: More sensitive and specific methods to detect anti-HLA antibodies before transplantation and sequential post-transplantation monitoring of these antibodies would be useful to identify patients who are at higher risk for allograft failure.

Primary immunodeficiencies of the B lymphocyte.

The immune response consists of two main components: humoral immunity represented by B lymphocytes and cellular immunity maintained by the T lymphocytes. Immunoglobulins, produced by B-lymphocytes, are the main mediators of humoral immunity, and deficiencies at this level affect the body's response to infection. Plasmocytes produce nine antibody izotypes: immunoglobulins G (IgG1, IgG2, IgG3, IgG4), immunoglobulins M (IgM), immunoglobulins A (IgA1, IgA2), immunoglobulins D (IGD) and immunoglobulins E (IgE). Primary hypogammaglobulinemias are characterized by the occurrence of recurrent infections and, paradoxically, by the occurrence of autoimmune diseases. Characteristic for these diseases is that symptoms occur at 7-9 months after birth, when transplacental antibody titers transmitted from the mother decrease, and the infant's body is unable to synthesize them to normal levels. Primary hypogammaglobulinemias are transmitted genetically, but mutations at the molecular level are still not fully understood. The most common are: Bruton agammaglobulinemia, transient newborn hypogammaglobulinemia, selective immunoglobulin deficiency and variable common immunodeficiency. Treatment consists of monthly antibiotics and immunoglobulins, depending on antibody titers (except for IgA deficiency).

Cytotoxic antibodies--valuable prognostic factor for long term kidney allograft survival.

BACKGROUND: Since the first attempts of kidney transplant, the inflammation mediated by T lymphocytes was considered one of the most important processes implicated in graft rejection but, multiple acute and chronic graft rejects revealed that the inflammation process is not singular and humoral mechanisms may play a role in the development of chronic vascular rejection. MATERIAL AND METHODS: We evaluated 500 Romanian patients registered on the kidney transplant waiting list. We performed anti-HLA class I and class II antibodies screening and identification. Laboratory tests were performed at Centre for Immunogenetics and Virology, Fundeni Clinical Institute, Bucharest, Romania. The methods used are represented by ELISA (GTI Diagnosis, USA) and Luminex (Tepnel, USA) RESULTS: pretransplant evaluation of the subjects illustrates that 145 patients (29%) have been sensitized and 355 patients (71%) have not been sensitized. The most frequent types of anti-HLA antibodies were A2 (13%), B42 (10%), DR7 and DR11 (13%). Post transplant, the most cases with de novo antibodies were observed in the first 6 months post transplantation. High serum levels of Il-2 Receptor, TNF-alpha and neopterin in post transplant sensitized patients were observed following de novo cytotoxic antibodies occurrence. CONCLUSION: post renal transplantation, patients present high risk in developing de novo cytotoxic antibodies, especially those who had HLA mismatch with the donor. These antibodies are predictors for acute graft rejection and for graft failure.

Enoxaparina y aspirina a bajas dosis en el tratamiento de los síndromes antifosfolípicos del embarazo. Seguridad y utilidad / Low dose enoxaparine and aspirin in the therapy of antiphospholipid syndromes in pregnancy. Safety and usefulness

La pérdida recurrente de embarazo constituye una complicación de los síndromes antifosfolipídicos, con graves consecuencias para las parejas, su entorno familiar y la sociedad. El objetivo de este estudio fue: determinar la efectividad de la heparina de bajo peso molecular (enoxaparina) asociada a bajas dosis de aspirinas, en mujeres con pérdidas recurrentes de embarazo (PRE) vinculada a la presencia de anticuerpos antifosfolípidos (aPL). Determinar la seguridad de estos tratamientos en la madre y en el feto vigilando la aparición de sangrado o plaquetopenia vinculada a la heparina. Para ello se identificó a una población de 76 mujeres con síndrome antifosfolipídico y PRE. Todas cursaron por lo menos un nuevo embarazo tratado con las drogas mencionadas. De 76 nuevos embarazos, 69 llegaron a término con por lo menos un hijo vivo. En la historia previa de las pacientes se registra un 3,8 por ciento de embarazos con hijos vivos mientras que cuando son tratadas 89,5 por ciento de los embarazos resultan exitosos (IC al 95 por ciento para la probabilidad de éxito del tratamiento indica que la misma está comprometida entre el 82,6 por ciento y el 92,4 por ciento). La comparación de proporciones indica que la diferencia es altamente significativa (p-valor del orden 10 a la -8). En relación a los efectos secundarios no se observaron sangrados fetales ni maternos ni plaquetopenias inducidas por heparina. Concluimos que el tratamiento con Enoxaparina y aspirina a bajas dosis es altamente efectivo y seguro para tratar los síndromes antifosfolipícos del embarazo y por lo tanto no debería esperarse PRE sino que las deberían estudiarse siempre que se sospeche el diagnóstico para poder tratarlas en forma adecuada.