Allo-anti-M: Detection peaks around 2 years of age, but may be attenuated by red blood cell transfusion.

BACKGROUND: Anti-M is frequently observed as a naturally occurring antibody of little clinical significance. Naturally occurring anti-M is often found in children although the specific triggers of production, persistence, and evanescence of anti-M have yet to be elucidated. METHODS: In a retrospective, multicenter, nationwide cohort survey conducted from 2001 to 2015, alloantibody screening was performed before and after transfusion in 18,944 recipients younger than 20 years. Recipients were categorized into six cohorts based on their age at transfusion; within and among these cohorts, allo-anti-M was analyzed in regard to its production, persistence, and evanescence. RESULTS: In 44 patients, anti-M detected before and/or after transfusion was an age-related phenomenon, with a median age of 2 years and an interquartile range of 1-3 years; anti-M was most frequently detected in a cohort of children 1 to <5 years (0.77%, 31 of 4035). At least five patients were presumed to have concurrent infections. Among 1575 adolescents/young adults (15 to <20 years), no anti-M was detected. Of 29 patients with anti-M prior to transfusion, the antibody fell to undetectable levels in 17 recipients (89.5%, of whom at least 13 received only M-negative red cells) after anywhere from 5 days to 5.8 years; anti-M persisted in 2, and was not tested in 10. Only 15 recipients (0.08%) produced new anti-M after transfusion. CONCLUSION: Naturally occurring anti-M is a phenomenon of younger ages, predominantly between 1 and 3 years. After transfusion, it often falls to undetectable levels.

Successful prenatal management of two foetuses affected by antibodies against GP.Mur with prenatal genotyping analysis and a literature review.

BACKGROUND: GP.Mur belongs to the GP(B-A-B) hybrid glycophorin family, which is the most common hybrid glycophorin in Southeast Asia. Antibodies against GP.Mur may cause a clinically significant haemolytic disease of the foetus and newborn (HDFN) although, so far, not many cases have been reported in mainland China. MATERIALS AND METHODS: Two Chinese women with a history of severe hydrops foetalis were seen in our centre. Alloantibody identification and GYP.Mur genotyping analysis were used for prenatal evaluation. Intrauterine transfusion was performed in two pregnancies in case 1. The features of these two women are described and literature-reported cases of HDFN related to antibodies against GP.Mur are summarised. RESULTS: The phenotype of both mothers was Mia- Mur-, while the fathers' was Mia+ Mur+ with a heterozygous GYP.Mur hybrid gene as determined by a high-resolution melting method of genotyping. In case 1, the antibodies against GP.Mur were detected in the mother's serum and the cord blood of two foetuses. Fortunately, the latest foetus was successfully saved after intrauterine transfusion. In case 2, hydrops foetalis occurred in the first two pregnancies, but the risk of HDFN was excluded for the third foetus because of the GP.Mur negative phenotype. The literature review showed that 68.8% (11/16) of the reported cases of HDFN related to antibodies against GP.Mur occurred in the Chinese population, and that 37.5% (6/16) of them were cases of severe HDFN. DISCUSSION: More cases of severe HDFN caused by antibodies against GP.Mur are presumably undetected as GP.Mur cells are not included in the panel of obligatory screening tests in most Southeast Asian countries including mainland China. The high-resolution melting method for GYP.Mur genotyping and zygosity detection is helpful in prenatal management.

A new antigen SUMI carried on glycophorin A encoded by the GYPA*M with c.91A>C (p.Thr31Pro) belongs to the MNS blood group system.

BACKGROUND: MNS is one of the highly polymorphic blood groups comprising many antigens generated by genomic recombination among the GYPA, GYPB, and GYPE genes as well as by single-nucleotide changes. We report a patient with red blood cell (RBC) antibody against an unknown low-frequency antigen, tentatively named SUMI, and investigated its carrier molecule and causal gene. STUDY DESIGN AND METHODS: Standard serologic tests, including enzyme tests, were performed. Monoclonal anti-SUMI-producing cells (HIRO-305) were established by transformation and hybridization methods using lymphocytes from a donor having anti-SUMI. SUMI+ RBCs were examined by immunocomplex capture fluorescence analysis (ICFA) using HIRO-305 and murine monoclonal antibodies against RBC membrane proteins carrying blood group antigens. Genomic DNA was extracted from whole blood, and the GYPA gene was analyzed by polymerase chain reactions and Sanger sequencing. RESULTS: Serologic screening revealed that 23 of the 541,522 individuals (0.0042%) were SUMI+, whereas 1351 of the 10,392 individuals (13.0%) had alloanti-SUMI. SUMI antigen was sensitive to ficin, trypsin, pronase, and neuraminidase, but resistant to α-chymotrypsin and sulfydryl-reducing agents. ICFA revealed that the SUMI antigen was carried on glycophorin A (GPA). According to Sanger sequencing and cloning, the SUMI+ individuals had a GYPA*M allele with c.91A>C (p.Thr31Pro), which may abolish the O-glycan attachment site. CONCLUSIONS: The new low-frequency antigen SUMI is carried on GPA encoded by the GYPA*M allele with c.91A>C (p.Thr31Pro). Neuraminidase sensitivity suggests that glycophorin around Pro31 are involved in the SUMI determinant.

Management of transfusion needs in a case of immunizing anti-M antibody in a patient with acute myeloid leukemia.

Anti-M is a relatively common "naturally occurring" antibody. Unexpected alloantibodies in patient's serum other than ABO isoagglutinins (e.g., anti-M) may cause a discrepancy in the reverse grouping. As long as anti-M does not react at 37°C, it is clinically insignificant for transfusion. However, we found this antibody to be of "immunizing" type which was reactive at 37°C and AHG phase and showing problems in blood grouping and crossmatch. This antibody had both IgM and IgG components. When "M" antibodies active at 37°C are encountered, antigen-negative or red cells that are compatible with an indirect antiglobulin test should be provided.

Fetal inheritance of GP*Mur causing severe HDFN in an unrecognized case of maternal alloimmunization.

BACKGROUND: The clinical and laboratory features of hemolytic disease of the newborn can be challenging to diagnose during pregnancy in the apparent absence of a blood group antibody. Low-frequency antibodies go undetected due to the lack of appropriate antigen-positive reagent red blood cells (RBCs). CASE REPORT: A pregnant woman of Southeast Asian descent was referred to a maternal-fetal medicine outpatient clinic due to a complicated obstetric history and a negative antibody screen. This initial visit at 29 weeks and 0 days' gestational age (GA) was unremarkable. A hydropic infant, born at 29 weeks and 5 days' GA, succumbed on the seventh day of life. Comprehensive laboratory testing was performed after birth. The hospital blood bank performed a maternal antibody identification. Direct antiglobulin test was performed on the cord blood. A reference laboratory confirmed an anti-Mia , performed paternal Mia phenotyping, and identified a hybrid glycophorin B-A-B GP*Mur allele. DISCUSSION: Maternal alloimmunization to low-frequency antigens remains a challenge. Southeast Asians make up a significant percentage in some US locations. Worldwide reports on the frequency of maternal alloimmunization of the MNS system can be used to guide the use of specific reagent RBCs for testing. Such strategies rely on the identification of blood donor units for reagent manufacture and use in perinatal antibody screens. CONCLUSION: The incidence of Mia and related antibodies is significant among Southeast Asians. In North America, prenatal antibody screening cells are not routinely chosen to match this population. The clinical and societal implications are discussed.

Acute hemolytic transfusion reaction associated with anti-Mta : case report and review of the literature.

BACKGROUND: Mta (MNS14) is a low-prevalence antigen of the MNS system. A few cases of hemolytic disease of the fetus and newborn caused by anti-Mta have been reported in the literature, but up to now this antibody has never been associated with a hemolytic transfusion reaction (HTR). CASE REPORT: A 38-year-old male with sickle cell disease undergoing exchange transfusion presented with shivering, nausea, dyspnea, and pain in the lower limbs. Biologic parameters showed increased hemolysis. The administered red blood cell (RBC) units had been issued by electronic crossmatch due to a negative antibody screening test. In the posttransfusion investigations, crossmatch of the transfused RBC units with the patient's serum showed incompatibility of one unit. The presence of an antibody against a low-prevalence antigen was suspected and further serologic testing was performed for identification. RESULTS: Anti-Mta was identified in the patient's serum. The RBCs of the incompatible unit implicated in the HTR were Mt(a+). An eluate of a posttransfusion blood sample of the patient was nonreactive with the incompatible RBCs, and the direct antiglobulin test was negative. CONCLUSION: To our knowledge, this is the first case report of an HTR associated with anti-Mta .

High immunogenicity of red blood cell antigens restricted to the population of African descent in a cohort of sickle cell disease patients.

BACKGROUND: Sickle cell disease (SCD) patients undergo multiple red blood cell (RBC) transfusions and are regularly exposed to low-prevalence (LP) antigens specific to individuals of African descent. This study evaluated the prevalence of antibodies against LP antigens in SCD patients and the need to identify these antibodies in everyday practice. STUDY DESIGN AND METHODS: Plasma from 211 SCD patients was tested with RBCs expressing the following LP antigens: RH10 (V), RH20 (VS), RH23 (DW ), RH30 (Goa ), KEL6 (Jsa ), and MNS6 (He). RESULTS: Nine LP antibodies were found in eight patients (3.8%): five anti-RH23, two anti-RH30, and two anti-MNS6. The exposure risk, calculated for each LP antigen, was below 3% per RBC unit, for all antigens tested. Thus, in this cohort of transfused SCD patients, the prevalence of LP antibodies was similar to that of antibodies against antigens of the FY, JK, and MNS blood group systems. These findings also reveal the occurrence of anti-RH23 in SCD patients. No anti-RH20 or anti-KEL6 were found, despite the high frequency of mismatch situations. CONCLUSION: These results highlight the immunogenicity of these LP antigens, and the evanescence of antibodies against LP antigens. They also highlight the importance of appropriate pretransfusion testing for patients frequently transfused, who are likely to be exposed to multiple types of blood group antigens.

Acute autoimmune hemolytic anemia due to anti-Ena autoantibody successfully treated with rituximab.

BACKGROUND: Autoimmune hemolytic anemia (AIHA) due to anti-Ena has been previously reported in association with massive intravascular hemolysis, disseminated intravascular coagulation, and fatal outcomes. Here we report a case of successfully treated AIHA due to anti-Ena . CASE REPORT: A 69-year-old male with a past medical history of cirrhosis due to nonalcoholic steatohepatitis status post-orthotopic liver transplant presented with 1-month history of progressive anemia. At presentation, his hemoglobin (Hb) was 5.6 g/dL, hematocrit (Hct) 16%, reticulocytes 0.3%, direct bilirubin (bili) 4 g/dL, lactate dehydrogenase 533 units/L (reference, 125-220 units/L), and haptoglobin 254 mg/dL (reference, 40-273 mg/dL). Blood bank testing revealed an autoantibody present in his plasma and a direct antiglobulin test positive for immunoglobulin G (IgC) but negative for complement. He received 1 unit of an incompatible blood group O phenotypically matched red blood cell unit. RESULTS: Over the course of the next 5 days, the Hb and Hct decreased to 4.1 g/dL and 12%, respectively, direct bili increased to 12.3 mg/day, reticulocytes slightly increased to 0.9%, and haptoglobin decreased to less than 8 mg/dL. Marrow study showed a hypercellular marrow with erythroid hyperplasia. Additional workup performed at a reference laboratory identified an anti-Ena autoantibody. He received prednisone and weekly rituximab infusions and was monitored weekly. At the 2-month visit, Hb and Hct were 10 g/dL and 32%, respectively. CONCLUSION: Unlike two of the previously reported fatal cases of AIHA with anti-Ena specificity, this 69-year-old male treated with weekly rituximab infusion underwent clinical recovery and significant anemia improvement.

Drug-induced immune hemolytic anemia associated with anti-vancomycin complicated by a paraben antibody.

BACKGROUND: Drug-induced immune hemolytic anemia (DIIHA) is rare, but potentially life-threatening. A high index of clinical suspicion is required for diagnosis, since the number of medications known to induce DIIHA continues to expand. Additionally, in vitro antibody reactivity against reagent additives has been reported, which may complicate test interpretation. CASE REPORT: A 61-year-old group A, D+ woman with a history of negative antibody detection tests developed hemolytic anemia on Postoperative Day 7 after repeat incision and drainage of a chronically infected right knee prosthesis. She was treated with multiple antibiotics in the postoperative period, including three cephalosporins and vancomycin intravenously as well as vancomycin and gentamicin-containing intraarticular cement spacers. STUDY DESIGN AND METHODS: A workup for possible DIIHA was performed. Testing was performed using vancomycin and cephalosporin antibiotics. Initially, gentamicin injection solution was used for testing, followed by testing with its component ingredients. RESULTS: A vancomycin antibody was detected and anemia resolved after vancomycin was discontinued. Reactivity was seen when gentamicin injection solution was used for testing, raising the possibility of a gentamicin antibody as well. However, testing with purified gentamicin as well as methylparaben and propylparaben demonstrated a paraben antibody that reacted with the paraben-containing gentamicin solution. The patient also demonstrated an anti-N. Neither the paraben antibody nor the anti-N appeared to cause in vivo hemolysis. CONCLUSION: This is the second reported case of DIIHA associated with anti-vancomycin. It is the fourth report describing a paraben antibody.

Anti-M antibodies as a cause of intrauterine fetal death and neonatal hyperbilirubinaemia.

A preterm male infant (35 weeks), appropriate for gestational age with birth weight of 2.20 kg was born to a 28-year G2 P0 mother. The mother's blood group was A positive and the father's was B positive. Her first pregnancy was an intrauterine fetal death due to immune hydrops. The mother's blood was positive for indirect Coomb's test with 1:32 dilution and anti-M antibodies. This pregnancy was induced at 35 weeks of gestation. Investigations from the cord blood revealed A positive blood group, positive direct Coomb's test, haematocrit of 41.4%, cord reticulocyte count of 5.3% and total serum bilirubin (TSB) of 2.7 mg/dL. Phototherapy was started at 27 h of life for visible jaundice. In view of progressive pallor and a sudden rise of bilirubin, the infant was subjected to exchange transfusion on day 5 of life. The transfusion was given with O negative and anti-M antibodies negative donor blood. Total serum bilirubin (TSB) prior to exchange transfusion was 28 mg/dL and packed cell volume (PCV) was 21%. Phototherapy was continued for a total duration of 8 days.

Hemolytic disease of the fetus and newborn with late-onset anemia due to anti-M: a case report and review of the Japanese literature.

Hemolytic disease of the fetus and newborn (HDFN) attributed to M/N-incompatibility varies from asymptomatic to lethally hydropic. Case reports are rare, and the clinical significance of anti-M is not completely understood. A challenging case of HDFN due to anti-M prompted an investigation of the Japanese literature, in order to characterize the clinical spectrum of M/N-incompatibility pregnancies in Japan and report results to English-language readers. Japanese reports of HDFN attributed to M/N incompatibility were compiled. Abstracted data include maternal antibody titers at delivery, fetal direct antiglobulin test, hemoglobin, total bilirubin, reticulocyte count at birth, and therapeutic interventions. We investigated characteristics of HDFN due to M/N-incompatible pregnancies in Japan after encountering a case of severe HDFN along with late-onset anemia in an infant born to a woman carrying IgG anti-M with a titer of 1. In total, thirty-three babies with HDFN due to anti-M and one due to anti-N have been reported in Japan since 1975. The median maternal antibody titer was 64 at delivery and was 16 or less in 10 of 34 women (29%). Five of 34 babies (15%) were stillborn or died as neonates. Twenty-one of 29 survivors (72%) had severe hemolytic anemia and/or hydrops fetalis. The reticulocyte count of neonates with anemia stayed below the reference interval. Sixteen (55%) developed late-onset anemia and 14 (48%) were transfused with M-negative RBCs. Significant positive correlation (P < .05) between the hemoglobin value and the reticulocyte count within 4 days of birth was obtained in 16 babies with anti-M HDFN. In the Japanese population, 21 of 34 cases of M/N-incompatible HDFN (72%) have manifested as severe hemolytic anemia and/or hydrops fetalis. Low reticulocyte count in neonates with late-onset anemia is consistent with suppressed erythropoiesis due to anti-M.

[Clinical and serological analyses of 70 erythrocyte allo-antibodies to MNS blood group system].

OBJECTIVE: To explore the occurrence and clinical significance of erythrocyte allo-antibodies to MNS blood group system among hospitalized patients in China. METHODS: The specificity and clinical features of erythrocyte allo-antibodies detected from August 2009 to July 2012 were retrospectively analyzed. RESULTS: A total of 187 erythrocyte allo-antibodies were detected from 66 042 hospitalized patients (0.28%) among which 70 (37.4%) were specific to MNS blood group system. Antibody frequencies were as follows: anti-M, 18.2%; anti-Mi(a), 18.2%; anti-S, 1.1%. Anti-Mi(a) was more frequent among transfused patients (16/34 vs 5/34, P = 0.004), and tended to be accompanied by other allo-antibodies. CONCLUSIONS: Antibodies to MNS blood group system are second only to Rh system as the most common erythrocyte allo-antibodies in China. And anti-Mi(a) is an important transfusion-related allo-antibody among the patients of southern ancestry.

[Research advances of genomic GYP coding MNS blood group antigens].

The MNS blood group system includes more than 40 antigens, and the M, N, S and s antigens are the most significant ones in the system. The antigenic determinants of M and N antigens lie on the top of GPA on the surface of red blood cells, while the antigenic determinants of S and s antigens lie on the top of GPB on the surface of red blood cells. The GYPA gene coding GPA and the GYPB gene coding GPB locate at the longarm of chromosome 4 and display 95% homologus sequence, meanwhile both genes locate closely to GYPE gene that did not express product. These three genes formed "GYPA-GYPB-GYPE" structure called GYP genome. This review focuses on the molecular basis of genomic GYP and the variety of GYP genome in the expression of diversity MNS blood group antigens. The molecular basis of Miltenberger hybrid glycophorin polymorphism is specifically expounded.

Anti-U-like as an alloantibody in S-s-U- and S-s-U+(var) black people.

BACKGROUND: S, s, and U antigens belong to the MNS system. They are carried by glycophorin B (GPB), encoded by GYPB. Black people with the low-prevalence S-s- phenotype, either U- or U+(var), can make a clinically significant anti-U. Anti-U-like, a cold immunoglobulin G autoantibody quite commonly observed in S-s+U+ black persons, was previously described to be nonreactive with ficin-, α-chymotrypsin-, and pronase-treated red blood cells (RBCs); nonreactive or weakly reactive with papain-treated RBCs; and reactive with trypsin-treated RBCs. Here we describe, in S-s- people from different molecular backgrounds, an alloantibody to a high-prevalence GPB antigen, which presents the same pattern of reactivity with proteases as autoanti-U-like. STUDY DESIGN AND METHODS: Four S-s- patients with an alloantibody to a high-prevalence GPB antigen were investigated by serologic and molecular methods. RESULTS: An alloantibody was observed in two S-s-U-/Del GYPB, one S-s-U+(var)/GYPB(P2), and one S-s-U+(var)/GYPB(NY) patients. As this alloantibody showed the same pattern of reactivity with proteases as autoanti-U-like, we decided to name it "anti-U-like." Anti-U-like made by the two S-s-U- patients was reactive with the S-s-U+(var) RBCs of the two other patients. CONCLUSION: S-s-U-/Del GYPB, S-s-U+(var)/GYPB(P2), and S-s-U+(var)/GYPB(NY) patients can make an alloanti-U-like. Anti-U-like made by S-s-U- people appears reactive with GYPB(P2) and GYPB(NY) RBCs, which both express a weak and partial U-like reactivity. We recommend transfusing S-s-U- RBCs in S-s-U- patients showing alloanti-U-like. Our study contributes to a better understanding of alloimmunization to GPB in black people and confirms importance of genotyping in S-s- patients, especially those with sickle cell disease to be frequently transfused.

Composition of erythrocytic (ABO, Rh-Hr, Kell, MN) group antigens characteristic of the Ozurgeti district's population.

Erythrocytic group antigens represent a genetically stably determined trait. Investigation of antigens of the said system in different regions is of the greatest importance in terms of both the creation of demographic data of the region as well as practical medicine, especially for transplantology and transfusiology. The peripheral or venous blood of 232 local natives (healthy donors) of Ozurgeti district of Guria region has been taken as the test subject. The test subject was taken by random methods in different vilifies (Bakhvi, Mshvidobauri, Ozurgeti, Likhauri, Gurianta, Bokhvauri, Dvadzu, Pampaleti) To identify the ABO, Rh-Hr, Kell, MN system antigens, an express-method using monoclonal antibodies has been applied. In studying the ABO system, it was fixed that the highest distribution frequency was characteristic of the 0(I) group (52.3±3.2%), then follows the group A(II) (38.5±3.2%). The distribution frequency of the B(III) group is (8.2±1.8%) and that of AB(IV)--(0.8±0.5). The population's 85.2±2.32% is the carrier of the Rh+ phenotypic group, while 14.7±2.3% belongs to the Rh-phenotypic group. In studying the concentration of alleles, the low concentration of p(K) allele was detected that equaled 0.2; the concentration of q(K) allele made 0.8, that of p(M)--0.65, and that of q (N) - 035.