|Year : 2020 | Volume
| Issue : 1 | Page : 78-79
Nirantara: A conservative approach to economical use of antisera in short-supply
Sanmukh R Joshi, Snehal B Senjaliya
Lok Samarpan Regional Blood Center, Research Section, Surat, Gujarat, India
|Date of Submission||25-Feb-2020|
|Date of Decision||03-Apr-2020|
|Date of Acceptance||03-Apr-2020|
|Date of Web Publication||17-Apr-2020|
Sanmukh R Joshi
Lok Samarpan Regional Blood Center, Research Section, Surat, Gujarat
Source of Support: None, Conflict of Interest: None
Background and Objectives: Serological screening for rare antigens may hamper due to scarcity of the reagent antisera. The study aims to develop a conservative approach for scarcely available antisera to maximize outcome from minimum resource. Method: In the LISS tube test for screening the antigen using antiserum, the test supernatant (TS) was harvested after reading the results. The TS was reused in subsequent screening till it showed visible reactivity. The stage at which it ceases to react, the TS was concentrated by carbo-wax (polyethylene glycol) and reused for further screening. Results: Using 8-10 ml of antiserum to rare antigen In(a), we could screen as many as 6868 donors and found 200 donors with In(a+); with 5 ml of anti-Di(a), we could screen 2567 local donors from the Western India; none of them was Di(a+), but four of the 87 Tibetan migrants were positive for the antigen. We could use this approach even on antibody to high-frequency antigen with a slight modification, by adding to the TS the antibody eluted from the sensitized test cell for using in subsequent screening. Conclusion: The recycling of antibody can fruitfully be used several times to conserve the antiserum in short-supply.
Keywords: Antisera, conservative approach, short-supply
|How to cite this article:|
Joshi SR, Senjaliya SB. Nirantara: A conservative approach to economical use of antisera in short-supply. Glob J Transfus Med 2020;5:78-9
| Introduction|| |
Screening for rare blood group antigens may be hampered due to scarcity of the reagent antisera. The short-supply also makes it an expensive maneuver too. With this view in mind, we have made a conservative approach that yields the maximum outcome with the minimum use of an available resource.
| Materials and Methods|| |
The standard serological tube method was used in screening the donors for rare red blood cell (RBC) antigen. Equal volume of 5% RBC suspension in saline, antiserum, and LISS was mixed and incubated at 37°C for 15 min. After centrifugation, the test supernatant (TS) was aspirated, pooled and saved in a clean tube, and labeled as TS1. The IAT steps were then performed on the sensitized RBCs in the test to record the results.
TS1 was used for further batch testing of the donors by mixing an equal volume of TS to the cell suspension. The LISS was not added at this time as it was already present in the TS from the previous test. A positive control using cells with heterozygous expression of the antigen in test was run in parallel to validate the results obtained. The TS was saved after each consecutive batch testing until it ceases to show reactivity. We could fruitfully use up to TS4, although, from TS2 onward, we had used increased volume of TS to the cell suspension, keeping the dilution factor in mind. Titer strength of the antibody in the original antiserum had guide on how many times such consecutive TS could be used and how much volume of the TS to be taken in each test. It was a matter of standardization although we could use up to TS4 of anti-In(a) having a titer-strength of 1:8 + 1 in the original serum and the grade of reaction with TS4 being 1+ agglutination by IAT. [Table 1] shows the strength of reactivity in the TS saved at different cycles of testing.
|Table 1: The strength of reactivity in the test supernatants harvested at different cycles of testing|
Click here to view
| Concentration of Test Supernatant|| |
The last TS that showed no reactivity was concentrated with the help of carbo-wax (polyethylene glycol) powder as follows:
A dialysis tube of required length was tied up at the one end with a thread, and through the other end, the accumulated TS was filled in and tied up. The tube was placed in a tray and the carbo-wax powder was sprinkled over and left at room temperature until a desired reduction in volume of the TS was visible. The tube was quiz-tight and tied with thread and dialyzed against large volume of normal saline to equilibrate the salinity. The tie was cut-opened at the one end, and the content was transferred into a clean tube that was labeled as “the first concentrate” and used for further batch screening in similar manner as that of the original serum. This maneuver could repeatedly be used as many times as desired.
| Results|| |
Using this approach, we could successfully screen 6868 donors using only about 8–10 ml of anti-In(a). Likewise, we had tested 2567 random donors from Gujarat region of the Western India by spending 5 ml of anti-Di (a) although none was Di(a+). On the other hand, we could find four Di(a+) individuals among 87 migrants from Tibet. Although the Di(a) is extremely rare antigen that found among the World populations tested, it is less uncommon among the oriental population groups and that of Native Americans.
| Discussion|| |
The antigens In(a) and Di(a) are rare, so a bulk of antibody molecules remain unused in the TS for recycling to screen further donors. However, antibody to high-frequency antigens (HFAs), say INRA (In5), would be consumed (absorbed out) by the red cells in the test; hence, its content might be reduced in the TS. We could still conserve the antibody with a slight modification. After the first batch of testing, the TS was fortified with the antibody molecules augmented by elution from the sensitized RBCs in the test. With this approach, we could test a total of 411 blood donors for the HFA INRA (In5) using a meager amount of 3 ml of the antiserum available to us.
There are quite a few rare bloods with the low-frequency antigen and the HFA on the record. Since corresponding antibodies are scarce, it becomes difficult to have the reagent antisera for the large-scale screening. The present approach may enable to carry out the screen program indefinitely with limited supply of the reagent antisera. The term “Nirantara” meaning “infinite” coined for this conservative approach seems the most appropriate for recycling the material to put in the best use. The method is simple, cost-effective, and easy to implement and proves beneficial to any who has miniscule facility yet has desire to do the job in the best possible manner. Therefore, we do not hesitate to recommend this approach to make maximum use of scarcely available antisera.
| Conclusion|| |
We conclude that the recycling of antibody can fruitfully be used numerous times that can help not only for conserving an antiserum in short-supply for the rare antigen typing but also proves economical in a large-scale screening program.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Marion Reid M, Lomas-Francis C. Olsson M. The Blood Group Antigen FactsBook. 3rd
ed. New York: Academic Press; 2012.