Effect of Combined HCV Therapy on Natural Killer Cell Activity.

Hepatitis C virus (HCV) is a major health problem all over the world with the highest prevalence reported in Egypt. Various treatment regimens have been developed over the last years. Interferon (IFN) based regimen was the standard of care regimen and then the IFN-free therapies were emerged. Host innate immunity through the activity of natural killer (NK) cell is one of the major players in competing infections and tumors, by producing perforin and granzymes that cause cytolysis of target cells, or by the production of various cytokines such as natural interferon gamma. Natural cytotoxicity receptors (NCRs), including Nkp30, Nkp44 and Nkp46, are a group of activating receptors that almost have restricted expression on the surface of NK cells and their density correlates with NK cytotoxicity. The role of these cells is not fully elucidated in patients with chronic HCV infection either treatment-naive or treatment experienced. Therefore, this study aimed to investigate the change that occurs in NK cell activity and cytotoxicity in response to successful elimination of HCV from blood after triple therapy with PEG-IFN-α, ribavirin and sofosbuvir. A total of 56 (50 male: 6 female) HCV patients with mean age of 41.6± 12.1 years were included in this study. They were divided into two groups: treatment naive group (20 patients) and the sustained virologic response (SVR) group (36 patients). All patients were investigated for their NK cell profile, NCRs, perforin and granzyme B expression by flow cytometry. Data was expressed as mean fluorescence intensity (MFI). Results revealed significant increase in MFI of granzyme B (P=0.001) and decrease in MFI of NKp30 (P=0.042) in the SVR group as compared to treatment naïve group. These findings indicated that triple therapy of HCV (IFN, Ribavirin and Sofosbuvir) effected NK activation and cytotoxicity.

Evaluation of molecular typing and serological methods in solving discrepant results of weak and partial D (Rh) in South Egypt.

INTRODUCTION: Rh discrepancies produced by partial and weak D phenotypes are a problem during routine testing. Some blood units with weak and partial D expression may be missed by serology. Overcoming the limitations of serology can be achieved by molecular typing. Our objective was to evaluate currently used serologic methods with the molecular analysis in solving discrepant results of weak and partial D (Rh) in South Egypt. PATIENTS AND METHODS: Fifty blood donor and patient samples with undetermined D phenotype were subjected to serology to define their phenotype using identification (ID)-Card "ID-partial RhD typing set" using six monoclonal anti-D panels, followed by molecular typing using polymerase chain reaction sequence-specific primer kit. RESULTS: Molecular typing confirmed most of the serology results; two samples previously resolved as partial D Type 3 and DFR by serological methods were clarified by molecular techniques - one sample as weak Type 4 and the other sample as weak Type 3. Among the weak D alleles found in our study, Type 4 was the most common, with a frequency of 20%, followed by Type 3 (14%), Type 1 (8%), Type 2 (6%), and finally, Type 5 with a frequency of 3%. The most common types of partial D were partial D Type D5 (14%) and Type D3 (10%). CONCLUSION: Our study identified D variants (weak D and partial D categories) of the antigen D and determined the frequency and composition of partial D and weak D alleles in our population. Molecular typing also confirmed most of the results obtained from serological methods.

Accumulation of B1-like B cells in transgenic mice over-expressing catalytically inactive RAG1 in the periphery.

During their development, B lymphocytes undergo V(D)J recombination events and selection processes that, if successfully completed, produce mature B cells expressing a non-self-reactive B-cell receptor (BCR). Primary V(D)J rearrangements yield self-reactive B cells at high frequency, triggering attempts to remove, silence, or reprogramme them through deletion, anergy induction, or secondary V(D)J recombination (receptor editing), respectively. In principle, expressing a catalytically inactive V(D)J recombinase during a developmental stage in which V(D)J rearrangement is initiated may impair this process. To test this idea, we generated transgenic mice expressing a RAG1 active site mutant (dnRAG1 mice); RAG1 transcript was elevated in splenic, but not bone marrow, B cells in dnRAG1 mice relative to wild-type mice. The dnRAG1 mice accumulate splenic B cells with a B1-like phenotype that exhibit defects in B-cell activation, and are clonally diverse, yet repertoire restricted with a bias toward Jκ1 gene segment usage. The dnRAG1 mice show evidence of impaired B-cell development at the immature-to-mature transition, immunoglobulin deficiency, and poorer immune responses to thymus-independent antigens. Interestingly, dnRAG1 mice expressing the anti-dsDNA 3H9H56R heavy chain fail to accumulate splenic B1-like cells, yet retain peritoneal B1 cells. Instead, these mice show an expanded marginal zone compartment, but no difference is detected in the frequency of heavy chain gene replacement. Taken together, these data suggest a model in which dnRAG1 expression impairs secondary V(D)J recombination. As a result, selection and/or differentiation processes are altered in a way that promotes expansion of B1-like B cells in the spleen.

Gads-deficient thymocytes are blocked at the transitional single positive CD4+ stage.

Positive selection of T-cell precursors is the process by which a diverse T-cell repertoire is established. Positive selection begins at the CD4(+)CD8(+) double positive (DP) stage of development and involves at least two steps. First, DP thymocytes down-regulate CD8 to become transitional single positive (TSP) CD4(+) thymocytes. Then, cells are selected to become either mature single positive CD4(+) or mature single positive CD8(+) thymocytes. We sought to define the function of Gads during the two steps of positive selection by analyzing a Gads-deficient mouse line. In Gads(+/+) mice, most TSP CD4(+) thymocytes are TCR(hi)Bcl-2(hi)CD69(+), suggesting that essential steps in positive selection occurred in the DP stage. Despite that Gads(-/-) mice could readily generate TSP CD4(+) thymocytes, many Gads(-/-) TSP CD4(+) cells were TCR(lo)Bcl-2(lo)CD69(-), suggesting that Gads(-/-) cells proceeded to the TSP CD4(+) stage prior to being positively selected. These data suggest that positive selection is not a prerequisite for the differentiation of DP thymocytes into TSP CD4(+) thymocytes. We propose a model in which positive selection and differentiation into the TSP CD4(+) stage are separable events and Gads is only required for positive selection.