• Korean Journal of Clinical Laboratory Science
• /
• v.48 no.1
• /
• pp.36-40
• /
• 2016

Red blood cell (RBC) alloimmunization results from genetic disparity of RBC antigens between donor and recipients. The discrepancy of RBC antibody screening test occurs when the results of red cell tests do not agree with those of the serum test. In order to select the proper blood units for transfusion, clarification of the cause of discrepancies is essential. The RBC antibody screening test is an easy, quick, and reliable method for detection of clinically significant antibodies. Antibody screening and identification is recommended prior to transfusion to determine whether there is blood group incompatibility. We reported that phenotyping for E, D, M, E+c, and C+e antibody screening test should be extended. Therefore, these results indicate that anti-D and anti-E alloantibodies were major risk factors for haemolytic disease of the newborn or delayed haemolytic transfusion reactions in this study population. We suggested that its antibody screening be adapted to blood safety interventions. Targeted screening of selected recipients at risk offers less value than universal antibody screening, and more research is needed to determine the real incidence of this national condition.

• Korean Journal of Clinical Laboratory Science
• /
• v.45 no.4
• /
• pp.164-169
• /
• 2013

Red cell alloantibodies other than naturally occurring anti-A or anti-B are called unexpected red cell antibodies, and can be detected by performing an antibody screening. The frequency and distribution of unexpected antibody identified in Asan Medical Center were analyzed. We investigated a total of 135,238 cases of antibody screening test in AMC for 3 years from 2010 to 2012. Using column agglutination techniques, antibody identification tests were performed for the cases with positive antibody screening. Among 135,238 cases, 854 (0.6%) cases showed positive results of antibody screening test. In the order of frequency, 284 (33.3%) anti-Rh, 89 (10.4%) anti-MNS, 62 (7.3%) anti-Lewis, 34 (4.0%) anti-Kidd, 10 (1.2%) anti-Duffy, and 9 (1.1%) anti-P were identified. Multiple antibodies were detected in 199 (23.3%) cases. Among 381 subjects investigated for transfusion history, 299 (78.5%) had history of transfusion while 82 (21.5%) had unknown history. Thus the incidence of unexpected antibody was higher in the group with history of transfusion than the group without (p<0.001). Also, among 435 subjects investigated for the history of pregnancy, 46 (10.6%) had no history while 389 (89.4%) had history of pregnancy, showing higher incidence of unexpected antibody in the group with history of pregnancy than the group without pregnancy (p<0.001). Evaluated amounts and frequency of antigen exposure due to transfusion and pregnancy is suggested to increase the frequency of identification of unexpected antibody.

• Biomedical Science Letters
• /
• v.12 no.1
• /
• pp.35-42
• /
• 2006

Alloimmunization to red blood cell (RBC) antigens may cause a delayed hemolytic transfusion reactions (DHTR) and a delayed serologic transfusion reactions (DSTR). In the present study, the frequency of alloimmunization and its clinical significance were evaluated. Also, transfusions were correlated with antibody formation. Alloimmunization rate was 0.63%. Alloimmunization rate in multiple transfused patients was 24.5%. The most common clinically significant alloantibodies of alloimmunized patients were found to be Rh antibodies (52.6%). Nine patients out of 38 (23.7%) became undetectable after the first detection. To be positive at antibody screening test after RBC transfusion was mean transfused numbers: 3.7 units, mean transfused periods: 56 days, mean transfused frequencies: 1.7 times. The results from antibody specificity and RBC transfusions were comparatively analyzed and it shows that Rh system antibodies were longer than other antibodies (P<0.05). In case of disease group, malignant diseases was longer than other diseases (P<0.05). In order to prevent the formation of RBC alloimmunization, irregular antibody screening tests were performed at propriety intervals in multiple transfused patients.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.7 no.3
• /
• pp.150-154
• /
• 2002

Monoclonal antibodies (Mabs) have been used as diagnostic and analytical reagents since hybridoma technology was invented in 1975. In recent years, antibodies have become increasingly accepted as therapeutics for human diseases, particularly for cancer, viral infection and autoimmune disorders. An indication of the emerging significance of antibody-based therapeutics is that over a third of the proteins currently undergoing clinical trials in the United States are antibodies. Until the late 1980's, antibody technology relied primarily on animal immunization and the expression of engineered antibodies. However, the development of methods for the expression of antibody fragments in bacteria and powerful techniques for screening combinatorial libraries, together with the accumulating structure-function data base of antibodies, have opened unlimited opportunities for the engineering of antibodies with tailor-made properties for specific applications. Antibodies of low immunogenicity, suitable for human therapy and in vivo diagnosis, can now be developed with relative ease. Here, antibody structure-function and antibody engineering technologies are described.

• BMB Reports
• /
• v.38 no.3
• /
• pp.290-293
• /
• 2005

In order to investigate the epitope of basic fibroblast growth factor (bFGF) and its immunogenicity, the epitopes of bFGF were screened from the phage display library with monoclonal antibody GF22, which can neutralize the bio-activity of bFGF. By three rounds of screening, the positive phage clones with bFGF epitopes were selected, which can effectively block the bFGF to bind with GF22. Sequence analysis showed that the epitopes shared a highly conservative sequence (Leu-Pro-Pro/Leu-Gly-His-Phe/Ile-Lys). The sequence of PPGHFK was located at 22-27 of the bFGF. The specific immuno-response of mouse could be highly induced by phage clones with the epitopes. And the anti-bFGF activity induced by LPGHFK was 3 times higher than the original sequence, which showed that the mimetic peptide LPLGHIK might be used as a tumor vaccine in the prevention and treatment of tumor.

• Korean Journal of Clinical Laboratory Science
• /
• v.42 no.2
• /
• pp.63-70
• /
• 2010

Antibody screening and identification tests before blood transfusion are important because unexpected red antibodies can cause acute or delayed hemolytic transfusion reactions. Although a tube method was used for detecting unexpected antibodies, a column agglutination method has recently been used because of its simple procedure and a high detection of warm antibodies. This study investigated the frequency and distribution of unexpected antibodies in transfusion candidates during the recent 5 years, and transfusion characteristics in the identified cases. From January 2005 to December 2009, 46,923 sera of the cases from E hospital were screened and 98 sera were identified by the DiaMed-ID System. 272 cases (0.58%) showed positive results out of all 46,923 cases that underwent unexpected antibodies screening. Among them, unexpected antibodies were identified in 98 cases. The anti-Rh antibodies included in warm antibodies were the most frequently detected in 47 cases (47.96%). Anti-Lewis and anti-MNSs antibodies were detected in 11 cases (11.22%) and 6 cases (6.12%), respectively. Unidentified antibodies were detected in 6 cases (6.12%). Among the patients with unexpected antibodies, 43 cases (43.88%) had a history of previous transfusion. Anti-E was the most frequently detected antibody (4/14 cases, 30.77%) in the cases who had a previous history of transfusion and showed different screening results from negative to positive, This study may provide the basic data for the frequency and characteristics of red cell antibodies.

• The Korean Journal of Blood Transfusion
• /
• v.23 no.2
• /
• pp.127-135
• /
• 2012

Background: Despite modern advances in laboratory automated medicine, work-process in the blood bank is still handled manually. Several automated immunohematological instruments have been developed and are available in the market. The IH-1000 (Bio-Rad Laboratories, Hercules, CA, USA), a fully automated instrument for immunohematology, was recently introduced. In this study, we evaluated the performance of the IH-1000 for ABO/Rh typing and irregular antibody screening. Methods: In October 2011, a total of 373 blood samples for ABO/Rh typing and 303 cases for unexpected antibody screening were collected. The IH-1000 was compared to the manual tube and slide methods for ABO/Rh typing and to the microcolumn agglutination method (DiaMed-ID system) for antibody screening. Results: For ABO/Rh typing, concordance rate was 100%. For unexpected antibody screening, positive results for both column agglutination and IH-1000 were observed in 10 cases (four cases of anti-E and c, three of anti-E, one of anti-D, one of anti-M, and one of anti-Xg) and negative results for both were observed in 289 cases. The concordance rate between IH-1000 and column agglutination was 98.7%. Sensitivity and specificity were 90.9% and 99.3%, respectively. Conclusion: The automated IH-1000 showed good correlation with the manual tube and slide methods and the microcolumn agglutination method for ABO-RhD typing and irregular antibody screening. The IH-1000 can be used for routine pre-transfusion testing in the blood bank.

• The Journal of the Korean life insurance medical association
• /
• v.12
• /
• pp.50-55
• /
• 1993

After a short historical resume, screening is discussed on the basis of the current philosophy of Life insurance compaines in leading countries. This is followed by considerations with regard to the future in areas of major bearing on Life insurance screening which have emerged as important within the last decade. HIV-antibody testing is dealt with from the screening point of view followed by aspects regarding the applicability of tumour marker use in Life insurance medicine. Last but not least genetic testing will be addressed, taking into account prospects for the future, as well as the resulting responsibility in medical and underwriting terms. The major considerations and suggested guidelines can be summarized as follows: 1) Screening in Life insurance is a prerequisite for underwriting and is a well-functioning selection instrument. 2) Screening technologies are medically well defined and have to follow general clinical rules, also in the future. 3) Screening parameters should follow the patterns of diseases according to age and risk groups. 4) Screening parameters for prognostic use are legitimate as long as they are considered in conjuction with clinical medical observations and rules. 5) Screening technologies of a sensitive nature require very special rules for handling in the sense of "consequential ethies". 6) Screening parameters like HIV-antibody testing require ongoing scientific feedback in their new testing dimensions. 7) Screening in the form of genetic testing is as yet not used in Life insurance; its potential future role in Life insurfance medicine must, however, be discussed responsibly and in time. 8) Screening enables the insurance industry to rule out possible antiselection and provide for equal knowledge on the part of the insurance applicant and the insurer about impairements which shorten life expectancy. 9) Screening, informed consent, counselling and confidentiality must go hand in hand both now and to an even greater extent in the future.

• Korean Journal of Clinical Laboratory Science
• /
• v.49 no.4
• /
• pp.390-394
• /
• 2017

Unexpected antibody screening and identification tests are highly important in the prevention of hemolytic transfusion reactions. Therefore, it is highly recommended to perform unexpected antibody screening test in all transfusion candidates. Here, the frequency and distribution of unexpected antibodies identified in Jeju for the past 3 years were evaluated. Between Jan 2014 and Dec 2016, unexpected antibody screening test was performed for 10,360 sera of transfusion candidates in Jeju general hospital using a column agglutination method with the Ortho BioVue system (Ortho-clinical Diagnostics, Raritan, NJ, USA). Eighty-seven (0.84%) of 10,360 cases that underwent unexpected antibiotics screening showed positive results. Among them, unexpected antibodies were identified in 41 cases (0.40%). Unidentified antibodies were detected in 8 cases (19.51%) and autoantibodies were detected in 3 cases (7.32%). The anti-E antibody included in warm antibodies were detected most frequently in 8 cases (19.51%); 6 cases (14.63%) of anti-E + anti-c antibody and 3 cases (7.32%) of $anti-Le^a+anti-Le^b$. $Anti-Le^a$ and $anti-Le^b$ antibodies were detected in 2 cases (4.88%), respectively. The anti-D, $anti-Di^a$, $anti-Fy^b$, $anti-Jk^a$, $anti-Jk^b$, anti-M and anti-P1 were detected in 1 case (2.44%). Complex antibodies were detected in 1 case (2.44%) in anti-C+anti-D and anti-E+anti-c+$anti-Jk^b$, respectively. In this study, we analyzed the frequency and distribution of unexpected antibodies in one general hospital for the past 3 years. However, there has been a general increase in multicultural families and foreign workers in Jeju, and it would be a meaningful study to compare the frequency and distribution of unexpected antibodies.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.3
• /
• pp.408-420
• /
• 2014

Yeast surface-displayed antibody libraries provide an efficient and quantitative screening resource for given antigens, but suffer from typically modest library sizes owing to low yeast transformation efficiency. Yeast mating is an attractive method for overcoming the limit of yeast transformation to construct a large, combinatorial antibody library, but the optimal conditions have not been reported. Here, we report a large synthetic human Fab (antigen binding fragment) yeast surface-displayed library generated by stepwise optimization of yeast mating conditions. We first constructed HC (heavy chain) and LC (light chain) libraries, where all of the six CDRs (complementarity-determining regions) of the variable domains were diversified mimicking the human germline antibody repertoires by degenerate codons, onto single frameworks of VH3-23 and $V{\kappa}1$-16 germline sequences, in two haploid cells of opposite mating types. Yeast mating conditions were optimized in the order of cell density, media pH, and cell growth phase, yielding a mating efficiency of ~58% between the two haploid cells carrying HC and LC libraries. We constructed two combinatorial Fab libraries with CDR-H3 of 9 or 11 residues in length with colony diversities of more than $10^9$ by one round of yeast mating between the two haploid HC and LC libraries, with modest diversity sizes of ${\sim}10^7$. The synthetic human Fab yeast-displayed libraries exhibited relative amino acid compositions in each position of the six CDRs that were very similar to those of the designed repertoires, suggesting that they are a promising source for human Fab antibody screening.