OBJECTIVETo analyze the results of irregular antibody screening and identification among patients before blood transfusion, and to investigate the specific distribution of irregular antibodies and the distribution regularity in different diseases.

METHODSChoosing the patients intended to be transfused in our hospital from January 1, 2009 to December 31, 2013 years, micro-column gel technique was used to screen the irregular antibodies of those receptors and to identify the antibody specificity of the positive specimens.

RESULTSAmong 44194 patients, 137 patients were with irregular antibody positive and their positive rate was 0.31%, among them 33 cases were male and accounted for 0.18% in the studied males; the 104 cases were females and accounted for 0.40% in all the studied females. The difference of sex distribution was statistically significant (X2=15.38, P<0.05). In the irregular antibody screening positive patients, patients with transfusion or pregnancy history were 129 cases, and the patients without transfusion or pregnancy history were 8 cases. In the irregular antibody screening positive patients, the main antibody of 54 cases belongs to Rh blood type system, accounting for 39.42%; The main antibody of 37 cases belongs to MNS blood type system, accounting for 27.01%; while the 30 cases belong to Lewis blood type system, accounting for 21.90%. According to the classification of diseases, the irregular antibody screening-positive patients with tumors were ranked in the highest rate at 5.96‰, the secondary hemorrhage of digestive tract and chronic renal failure were ranked at the rate of 3.28‰ and 3.19‰. The difference of positive rates between diseases was statistically significant (χ2=19.33, P<0.05).

CONCLUSIONIrregular antibody screening before blood transfusion is necessary, which can discover the irregular antibodies of clinical significance, especially for patients with tumors and the other patients with the history of frequent blood transfusions or multiple pregnancies. Antibody screening is a useful warning signal, as it ensures the safety of blood transfusions.

Antibodies ; Blood Group Antigens ; Blood Grouping and Crossmatching ; Blood Transfusion ; Female ; Gastrointestinal Tract ; Humans ; Lewis Blood-Group System ; Male ; Pregnancy ; Rh-Hr Blood-Group System

OBJECTIVE: To establish a new method for synthesizing Lewis blood group antigens, that is, the mimotopes of Lewis blood group antigens were screened by using an alpaca phage display nanobody library. METHODS: We selected mimotopes of the Lewis a (le^a) antigen by affinity panning of an alpaca phage display nanobody library using a monoclonal anti-le^a antibody. Enzyme-linked immunosorbent assay (ELISA) was used to test the affinity of the positive clones for the monoclonal anti-le^a antibody, and the high-affinity positive clones were selected for sequencing and synthesis. Finally, the sensitivity, specificity and reactivity of the synthesized le^a mimotope in clinical samples were verified by ELISA. RESULTS: A total of 96 phage clones were randomly selected, and 24 were positive. Fourteen positive clones with the highest affinity were selected for sequencing. The result showed that there were 5 different sequences, among which 3 sequences with the highest frequency, largest difference and highest affinity were selected for expression and synthesis. The sensitivity and specificity of le^a mimic antigen by ELISA showed that, the minimum detection limit of gel microcolumn assay (GMA) and ELISA method were 25 times different, and the le^a mimic antigen had no cross reacted with the other five unrelated monoclonal antibodies(P<0.001). Finally, 30 clinical plasma samples were analyzed. The mean absorbance of the 15 positive plasma samples was significantly higher than that of the 15 negative plasma samples (P=0.02). However, the positive signal values of the clinical samples were much lower than those of the monoclonal antibodies. CONCLUSION A new method of screening le^a mimic antigen by using alpaca phage nanoantibody library has been established, which is expected to realize the screening of le^a mimotopes, thus realizing the application of high-sensitivity detection methods such as ELISA and chemiluminescence in blood group antibody identification.
Animals ; Antibodies, Monoclonal ; Antineoplastic Agents, Immunological ; Bacteriophages ; Blood Group Antigens ; Camelids, New World ; Enzyme-Linked Immunosorbent Assay/methods* ; Epitopes ; Humans ; Lewis Blood Group Antigens ; Peptide Library

Human noroviruses (huNoVs) recognize histo-blood group antigens (HBGAs) as attachment factors, in which genogroup (G) I and GII huNoVs use distinct binding interfaces. The genetic and evolutionary relationships of GII huNoVs under selection by the host HBGAs have been well elucidated via a number of structural studies; however, such relationships among GI NoVs remain less clear due to the fact that the structures of HBGA-binding interfaces of only three GI NoVs with similar binding profiles are known. In this study the crystal structures of the P dimers of a Lewis-binding strain, the GI.8 Boxer virus (BV) that does not bind the A and H antigens, in complex with the Lewis b (Le(b)) and Le(y) antigens, respectively, were determined and compared with those of the three previously known GI huNoVs, i.e. GI.1 Norwalk virus (NV), GI.2 FUV258 (FUV) and GI.7 TCH060 (TCH) that bind the A/H/Le antigens. The HBGA binding interface of BV is composed of a conserved central binding pocket (CBP) that interacts with the β-galactose of the precursor, and a well-developed Le epitope-binding site formed by five amino acids, including three consecutive residues from the long P-loop and one from the S-loop of the P1 subdomain, a feature that was not seen in the other GI NoVs. On the other hand, the H epitope/acetamido binding site observed in the other GI NoVs is greatly degenerated in BV. These data explain the evolutionary path of GI NoVs selected by the polymorphic human HBGAs. While the CBP is conserved, the regions surrounding the CBP are flexible, providing freedom for changes. The loss or degeneration of the H epitope/acetamido binding site and the reinforcement of the Le binding site of the GI.8 BV is a typical example of such change selected by the host Lewis epitope.
Binding Sites ; Blood Group Antigens ; chemistry ; immunology ; Caliciviridae Infections ; immunology ; virology ; Crystallography, X-Ray ; Epitopes ; chemistry ; immunology ; Evolution, Molecular ; Humans ; Lewis Blood-Group System ; chemistry ; immunology ; Norovirus ; chemistry ; immunology ; pathogenicity ; Protein Binding ; Viral Proteins ; chemistry ; immunology