A case of IgG anti-Lea antibody detected

foreword

Irregular antibody screening is one of the items that must be checked before blood transfusio.

case after

The patient, a female, 85 years old, was admitted to the hospital because of "repeated chest tightness and shortness of breath for 1 month", with cough, phlegm and blood, no fever, sore throat, nasal congestion, runny nose, chills, and muscle pain in the limb.

Past history: A history of hypertension was found for more than 2 years, the highest blood pressure was 200/98 mmHg, and he was taking antihypertensive drug.

Physical examination: clear, slightly short of breath, nasal cannula oxygen inhalation, low breath sounds in the left lung, no dry or wet rales were hear.

Auxiliary examination: blood routine showed that the number of red blood cells decreased, hemoglobin decreased, and hematocrit decrease.

Blood type + anti-screening results:

The patient's blood type is RhD positive for type A, positive for irregular antibody screening (I: 0, II: 2+, III: 0, detected by Osendo automatic blood type instrument column agglutination method), and the antibody screening result of saline test tube method is negativ.

Direct antiglobulin test: multispecific anti-human globulin, monospecific anti-IgG, and monospecific anti-C3 were all negativ.

The patient presented with moderate anemia and planned to receive blood transfusion therap.

After infusion of 2U of suspended red blood cells that are compatible with blood by saline method, polybrene method, and microcolumn gel method, the patient's hemoglobin increased from 57g/L to 67g/L, and no allergy, hemolysis and other blood transfusion reactions occurred, and the therapeutic effect reached the expected leve.

case analysis

The patient was admitted to the hospital and was found to have moderate anemia, and he planned to undergo blood transfusio.

After being sent to the reference laboratory of Shanghai Blood Center for further identification, it was confirmed that there was IgG anti-Lea antibody in the patien.

Under normal circumstances, about 80% of human erythrocytes have Leb antigens, while only 20% of erythrocytes have Lea antigen.

Most of Lewis blood group system antibodies are naturally produced, mainly IgM type, with complement-binding propertie.

Numerous literature reports have shown that in recent years, the detection rate of Lewis blood group antibodies in the pre-transfusion irregular antibody screening has been on the rise, and some literatures have reported that Lewis blood group antibodies can cause neonatal hemolytic disease and blood transfusion reaction.

Lewis blood group antibodies of IgG or IgG+IgM are still reactive at 37°C, which is of certain clinical significanc.

Case development

The Lewis blood group system gene is FUT3, and the International Society for Blood Transfusion is named LE (ISBT007.

The Lewis gene (FUT3) encodes a glycosyltransferase that catalyzes a fucosyl to H substance in the secretion fluid to produce Leb antigen; if it is non-secreted and has no H antigen, it catalyzes a fucosyl to pre-H On the body material, the Lea antigen is produce.

Lewis blood group substances are widely distributed in the human body and are not synthesized in the erythrocyte lineage, but are tissue-blood group antigen.
Lewis antigens on red blood cells come from the adsorption of glycosphingolipids in plasma, and Leb substances are preferentially adsorbed over Lea substance.
Lea antigens begin to appear 10 days after birth, and Leb antigens begin to appear in the second month of lif.
Lea antigens may gradually subside in the second year, and Lewis blood type cannot be correctly identified until after the age of 6.

Anti-Lea antibodies are mainly IgM-type antibodies, which can bind complement, usually do not react at 37 °C, do not cause hemolytic transfusion reaction or hemolytic disease of the newborn, usually only appear in the plasma of Le(ab-) phenotype individuals Lea (a-b+) individuals do not produce anti-Lea antibodies, because such individuals contain a small amount of Lea soluble antigen in their plasma, which can neutralize anti-Lea antibodie.

Case summary

In clinical work, attention should be paid to the detection of antibodies of the Lewis blood group syste.
The existence of this antibody can interfere with the results of blood group serology testing, which not only has a certain impact on the clinical blood transfusion effect, but also is not conducive to the safety of clinical blood transfusio.
Cross-matching is the last barrier to safe blood transfusion in clinical practic.
For patients who have detected specific antibodies, a variety of cross-matching methods should be used, and red blood cell transfusions that are compatible with each method should be given to avoid the occurrence of hemolytic transfusion reaction.
To ensure the safety and effectiveness of clinical blood transfusio.

Expert Reviews

Immune stimuli such as blood transfusion and pregnancy can cause the body to produce unexpected antibodies (irregular antibodies.
Although most of Lewis blood group system antibodies are naturally produced, there are still a small amount of IgG-type antibodies, which can cause hemolytic transfusion reaction.
In order to ensure clinical blood transfusion It is safe and effective, and the missed detection of such antibodies should be avoided in clinical wor.

Commenting expert: Yang Ji, deputy chief technicia.

references:

[1] Zhang Ye, Liu Sufang, Zhang Lei, et a.
Study on antibodies of Lewis blood group system [J.
Beijing Medicine, 2015, 37(6): 592-59

[2] Dang Panyu, Wang Wenting, Liu Zhixin, et a.
Analysis of Lewis blood group system antibody detection and discussion on clinical blood transfusion strategy [J.
Journal of Modern Laboratory Medicine, 2019, 34(3): 128-13

[3] He Kunhua, Ma Liqiong, Ba Xuejia.
A case report of IgG anti-Lea detected in preoperative blood preparation [J.
Laboratory Medicine and Clinic, 2019, 16(8): 1147-115