anti-D Antibodies Research Articles

CGRA10: A RARE CASE OF ANTI‐KU ANTIBODIES POSITIVE SYSTEMIC LUPUS ERYTHEMATOSUS AND JUVENILE DERMATOMYOSITIS OVERLAP IN A PAEDIATRIC PATIENT

We describe the case of a 14 year old previously healthy girl who presented with fevers, joint and muscle pains, increasing proximal muscle weakness, facial butterfly rash and heliotrope rash of the eyelids for a month. The investigations showed anaemia, thrombocytopenia, low complement C3 and C4 and raised erythrocyte sedimentation rate, lactate dehydrogenase, hepatic transaminases and creatine kinase 6898 U/L (reference range 15–180). The auto-immune screen showed elevated antinuclear antibodies (speckled pattern) >2560 (reference range 0–79), anti-DS DNA antibodies 34 kIU/L (reference range 0–7) and detection of ribonuclear protein, ribosomal P, anti-smith and anti-Ku antibodies. Bone marrow aspirate and C-reactive protein were normal. Magnetic Resonance Imaging (MRI) showed extensive symmetrical truncal and bilateral lower limb muscle oedema. The skin biopsy showed interstitial dermal inflammation with lymphocytes and perivascular inflammation. She was treated with systemic corticosteroids, physiotherapy based on Childhood Myositis Assessment Scale and azathioprine with dramatic improvement. Based on clinical presentation and investigations, a diagnosis of SLE and JDM with overlapping features was made. Our patient is a rare case of anti-Ku antibodies positive SLE and JDM overlap who rapidly responded to immunosuppressive treatment. MRI is a useful diagnostic tool in childhood inflammatory myopathy. Invasive procedures such as muscle biopsy and electromyography are less frequently used in a typical presentation such as our case. Anti-Ku antibodies are rare, with an estimated prevalence of 0.5% of all ANA-positive sera. These antibodies are present in about 2.5 percent of patients with systemic sclerosis in association with myositis and arthritis. Anti-Ku antibodies may also be detected in patients with SLE.

Antibody-mediated immune suppression is improved when blends of anti-RBC monoclonal antibodies are used in mice

AbstractAlthough the prevention of hemolytic disease of the fetus and newborn is highly effective using polyclonal anti-D, a recombinant alternative is long overdue. Unfortunately, anti-D monoclonal antibodies have been, at best, disappointing. To determine the primary attribute defining an optimal antibody, we assessed suppression of murine red blood cell (RBC) immunization by single-monoclonal antibodies vs defined blends of subtype-matched antibodies. Allogeneic RBCs expressing the HOD antigen (hen egg lysozyme [HEL]–ovalbumin–human transmembrane Duffyb) were transfused into naïve mice alone or together with selected combinations of HEL-specific antibodies, and the resulting suppressive effect was assessed by evaluating the antibody response. Polyclonal HEL antibodies dramatically inhibited the antibody response to the HOD antigen, whereas single-monoclonal HEL antibodies were less effective despite the use of saturating doses. A blend of monoclonal HEL-specific antibodies reactive with different HEL epitopes significantly increased the suppressive effect, whereas a blend of monoclonal antibodies that block each other's binding to the HEL protein did not increase suppression. In conclusion, these data show that polyclonal antibodies are superior to monoclonal antibodies at suppressing the immune response to the HOD cells, a feature that can be completely recapitulated using monoclonal antibodies to different epitopes.

Detection of anti-ds DNA Antibodies in Iraqi Patients Suspected with Systemic Lupus Erythematosus (SLE).

31Jul 2016 Detection of anti-ds DNA Antibodies in Iraqi Patients Suspected with Systemic Lupus Erythematosus (SLE). Ishraq Hasan Elewi , Dr. Suhad Faisal Hatem Al-Mugdadi and Qabas Nather Latef. Pharmacy College/Al-Mustansriyah University. Iraq.

A D+ blood donor with a novel RHD*D-CE(5-6)-D gene variant exhibits the low-frequency antigen RH23 (D(W) ) characteristic of the partial DVa phenotype.

Blood donors whose red blood cells (RBCs) exhibit a partial RhD phenotype, lacking some D epitopes, present as D+ in routine screening. Such phenotypes can exhibit low-frequency antigens (LFAs) of clinical significance. The aim of this study was to describe the serologic and genetic profile for a blood donor with an apparent D+ phenotype carrying a variant RHD gene where D Exons 5 and 6 are replaced by RHCE Exon (5-6). Anti-D monoclonal antibodies were used to characterize the presentation of RhD epitopes on the RBCs. RHD exon scanning and DNA sequencing of short- and long-range polymerase chain reaction amplicons were used to determine the RHD structure and sequence. Extended phenotyping for LFAs RH23 (D(W) ) and Rh32 was performed. The donor serology profile was consistent with partial RhD epitope presentation. The donor was hemizygous for an RHD variant allele described as RHD*D-CE(5-6)-D hybrid. The RHCE gene insert is at least 3.868 kb with 5' and 3' breakpoints between IVS4 + 132-c.667 and IVS6 + 1960-IVS6 + 2099, respectively. The sequence for this hybrid was assigned GenBank Accession Number KT099190.2. The RBCs were RH23 (D(W) )+ and Rh32-. A novel RHD*D-CE(5-6)-D hybrid allele encodes a partial RhD epitope and carries the LFA RH23 (D(W) ). This and the epitope profile resemble the partial DVa phenotype. Given that RBCs from this individual lack some RhD epitopes, there is an alloimmunization risk if the donor is exposed to D+ RBCs. Conversely, transfusions of RH23 (D(W) )+ cells to RH23 (D(W) )- recipients also pose an alloimmunization risk.

Effects of 1,25-dihydroxyvitamin D3 on IL-17/IL-23 axis, IFN-γ and IL-4 expression in systemic lupus erythematosus induced mice model.

Systemic lupus erythematosus (SLE) is a multi-factorial autoimmune disease which may be characterized by T lymphocytes dysfunctions. Th17 cells have been identified as new effector cells, which play an important role in the pathogenesis. In recent years, immunomodulatory effect of vitamin D3 has been noticed. In the present experiment, the effect of vitamin D3 on the expression of IL-17, IL-23, IL-4 and IFN-γ were assessed in activated chromatin-induced mouse model for SLE. Five groups of mice were included in this study; Group one received active chromatin +CFA + PBS; Group 2 received vitamin D3 starting 2 weeks before disease induction; Group 3 received vitamin D3 (50 ng/day) starting with the disease establishment; Group 4 received non active chromatin +CFA + PBS; Group 5 received CFA + PBS. On day 56 splenocytes were isolated and gene expression of interleukin IL-17, IL-23, IL-4 and IFN-γ were analyzed by Real-Time PCR method. Proteinuria and serum anti-dsDNA and Th17 levels were measured using commercial kits. The results showed that IL-17, IL-23, and IFN-γ mRNA expression, and IL-17 titers were decreased remarkably and that of IL-4 increased in mice which received vitamin D3 before SLE induction. Administration of vitamin D3 after the establishment of SLE failed to affect the IL-17 or IL-23 mRNA levels. Lastly, pre-treatment of mice with vitamin D3 decreased the anti-ds DNA antibody titer. Our findings showed that vitamin D3 supplementation in lupus induced mice through modulating the expression rate of some inflammatory cytokines diminished the inflammatory conditions in SLE.

Rapid detection of diethylstilbestrol using a quartz crystal microbalance with gold nanoparticals amplification

To develop a quartz crystal microbalance (QCM) immunosensor with high sensitivity and selectivity for the rapid detection of diethylstilbestrol. Dextran was used as reducing agent for preparing gold nanoparticles (AuNPs) with the size of 40 nm. The AuNPs were coupled with anti-DES antibody after amination. A monolayer was generated after immersing the quartz crystal into the solution of 5 mmol/L 11-mercaptoundecanoic acid(MUA) for 16 hours. After the monolayer was activated by 1-ethyl-3-(3-dimethylaminopropry) carbodiimide hydrochloride (EDC·HCl) and N-hydrosuccinimide (NHS), 20 μl of 2.2 mg/ml DES-HS-BSA was dropped onto the surface of crystal to prepare a sensitive membrane which can recognize DES specifically. Then, 50 μl of 1 mol/L ethanolamine (pH 8.5) was used to seal the carboxylic groups to make the sensitive membrane which could identify DES specifically. QCM immunosensor was used as detection platform to optimize the reaction conditions. Under the optimized conditions, 10 μl of 28 μg/ml AuNPs-antibody was mixed with 10 μl of 0.03-2.5 μg/ml DES, and the mixture was added on the sensitive membrane. QCM immunosensor was used to detect the signals and the standard curve was obtained at the same time. The detection limit was calculated based on the standard curve. The specificity was evaluated by testing DES and its analogues with the same concentration. The optimized concentration for the immobilization of DES-HS-BSA on the surface of QCM was 2.2 mg/ml. The optimized concentration for coupling anti-DES antibody with AuNPs was 7 μg/ml and 15 nmol/L, respectively. The optimized concentration of AuNPs-antibody was 14 μg/ml. The logarithm of DES concentration was proportional to the frequency shift in the range of 0.16-500 ng/ml, Δf=-24.170 lgCDES+69.71, R(2)=0.998. The detection limit of this method was 0.13 ng/ml. DES analogues could not influence the detection of DES obviously, so the sensor had good specificity. The quartz crystal microbalance immunosensor with gold nanoparticals amplification could detect DES sensitively and rapidly.

Anti-D Antibodies in Pregnant D Variant Antigen Carriers Initially Typed as RhD+

Background: To evaluate the incidence, the consequences, and the prevention strategy of anti-D alloimmunizations of D variant carriers in the obstetric population of Split-Dalmatia County, Croatia. Methods: RhD immunization events were evaluated retrospectively for the period between 1993 and 2012. Women were tested for RhD antigen and irregular antibodies. Those with anti-D antibody who were not serologically D- were genotyped for RHD. They were evaluated for their obstetric and transfusion history and their titer of anti-D. The neonates were evaluated for RhD status, direct antiglobulin test (DAT), hemoglobin and bilirubin levels, transfusion therapy as well as phototherapy and outcome. Results: Out of 104,884 live births 102,982 women were tested for RhD antigen. Anti-D immunization occurred in 184 women which accounts for 0.9% of individuals at risk of anti-D formation. 181 cases occurred in women serologically typed as D-. Three women were partial D carriers (DVa n = 2, DNB n = 1), initially typed RhD+, and recognized as D variant carriers after the immunization occurred. Anti-D titer varied from 1:1 to 1:16. Six children were RhD+, four had positive DAT, and two underwent phototherapy. Conclusion: Anti-D immunization occurred in pregnant partial D carriers (DVa, DNB). RhD+ children had serologic markers of hemolytic disease of the fetus and newborn (HDFN), with no cases of severe HDFN.

RHD Zygosity Determination from Whole Genome Sequencing Data

In the Rh blood group system, the RHD gene is bordered by two homologous DNA sequences called the upstream and downstream Rhesus boxes. The most common cause of the D− phenotype in people of European descent is a deletion of the RHD gene region, which results in a hybrid combination of the two Rhesus boxes. PCRbased testing can detect the presence or absence of the hybrid box to determine RHD zygosity. PCR hybrid box testing on fathers can stratify risk for haemolytic disease of the fetus and new born in mothers with anti-D antibodies. Red blood cells and genomic DNA were isolated from 37 individuals of European descent undergoing whole genome sequencing as part of the MedSeq Project. A whole genome sequence-based RHD sequence read depth analysis was used to determine RHD zygosity (homozygous, hemizygous, or null states) with 100% agreement (n=37) when compared to conventional RhD serology and PCR-based hybrid box assay.

Molecular serological characteristics of weak D antigen types of the Rhesus system

to estimate the spread of weak D antigen types of the Rhesus system in the citizens of the Russian Federation and a possibility of serologically identifying these types. The red blood cells and DNA of people with weakened expression of D antigen were investigated using erythrocyte agglutination reaction in salt medium (2 methods); agglutination reaction in the gel columns containing IgM + IgG anti-D antibodies, indirect antiglobulin test with IgG anti-D antibodies (2 methods); polymerase chain reaction to establish the type of weak D. A rhesus phenotype was determined in 5100 people in 2014-2015. The weakened agglutinable properties of red blood cells were detected in 102 (2%) examinees. 63 examinees underwent genotyping to identify the variants of the weak D antigen, which identified 6 weak D types. There were the most common weak D types 3 (n=31 (49.2%)) and weak D type 1 (n=18 (28.6%)), including weak D type 1.1 in one (1.6%) case. The other 4 weak D antigen types were as follows: weak D type 2 (14.3% (n=9)), weak D type 15 (4.8% (n=3)), weak D type 4.2 (DAR) (1.6% (n=1)) and weak D type 6 (1.6% (n=1)). The antiglobulin test in the gel column containing antiglobulin serum was the most sensitive serological assay to identify the weak D antigen. Only a molecular test could establish weak D type 15 in 2 samples of red blood cells with Ccdee and ccdEe phenotypes. The weak D antigen could be serologically identified in 96.8% of cases. When testing for weak D, particular attention should be given to people with the D-negative phenotype who had the C or E antigens. Our investigations conducted for the first time in Russia will be able to improve the immunological safety of red blood cell-containing medium transfusions for patients.

IgG Alloantibodies Against RBC Induced By Pregnancy or Transfusion Have Unique Glycosylation Patterns Which Correlate with Clinical Outcome of Hemolytic Disease of the Fetus or Newborn

Hemolytic disease of the fetus or newborn (HDFN) is a potentially life-threatening disease in which red blood cells (RBC) of the child are destroyed by maternal IgG alloantibodies. HDFN caused by anti-D antibodies is well known, but may also occur due to other RBC antibody specificities, with anti-K, anti-c and anti-E being most frequently implicated (Koelewijn et al. Transfusion 2008;48(5):941-52). Besides alloantibody-mediated RBC destruction, anti-K also impairs erythropoiesis. The composition of the sugar moiety of the IgG-Fc tail influences the binding affinity to IgG Fc receptors (FcγR) on effector cells. Particularly, the absence of core fucose increases the binding of IgG to FcγRIIIa and FcγRIIIb. In previous studies we observed a correlation between fucosylation of anti-D and anti-platelet antibodies with severity of disease in patients with HDFN (n=8) or fetal or neonatal alloimmune thrombocytopenia (FNAIT) (n=48) (Kapur et al Br.J.Haematol. 2014 166 (6): 936-945; Kapur et al Blood 2014;123(4):471-80). The aim of this study was to investigate whether skewed antibody glycosylation also applies to other anti-RBC antibodies and if this is related to the immunization route and disease severity. Clinical data were collected for 146 women with anti-K, c or E antibodies. Anti-K (n=30), anti-c (n=69) and anti-E (n=47) antibodies were purified from serum by acid elution after incubation of the serum with matching positive RBC using antigen-negative RBC as negative-control for specificity of the procedure. Anti-RBC specific IgG antibodies and total IgG antibodies were subjected to tryptic digestion and resulting IgG1 Fc-derived glycopeptides analyzed by MALDI-TOF-Mass Spectrometry. Lowered fucosylation was observed for anti-K IgG (average 75.7% compared to 92.1% of total IgG, p<0.0001), but less than observed for anti-D IgG1 (52.29%, p=0.0008). Also fucosylation of anti-E IgG was lowered (91.1%, p=0.02), but significantly less pronounced then anti-K and anti-D. Surprisingly, anti-c fucosylation was not significantly skewed (89.9%, p=0.25), but with lowered fucose down to 60% in a few anti-c cases. Anti-E is in most cases naturally occurring, which was definitively proven in 17 cases without history of transfusion or E-positive pregnancy. Anti-K is in most cases induced by transfusion (Koelewijn et al BJOG 2009;116 (10): 1307-1314). Analyzing only cases of mothers with blood transfusion history and antigen negative fathers (n=15) also showed lowered fucosylation (p=0.014), suggesting that signatures of low IgG-fucosylation are not related to pregnancy responses. In 113 antigen-positive newborns at risk for HDFN (K: n=16, c: n=62, E: n=35), the glycosylation pattern of the specific IgG correlated with anaemia and severity of jaundice. For anti-K, galactosylation and sialylation correlated with hemoglobin (r=-0.78 ,p=0.0015, and r=-0.59, p=0.0303, resp.). Similar correlations were found with hematocrit levels. A low anti-c fucosylation correlated with increased bilirubin level (r=-0.38, p=0.0186) and severity of jaundice (r=-0.35, p=0.0103). Newborns exposed to anti-c that required a blood transfusion showed significantly lower galactosylation and higher bisection (p=0.03, p=0.01 resp.). In conclusion, we found similar skewing of antigen-specific IgG1 glycosylation for anti-E and anti-K as observed for anti-D and anti-platelet antibodies, although less pronounced. This skewing was not related to the immune response being induced in pregnancy, as similar features were also observed after transfusion. Interestingly, natural anti-E antibodies, probably evoked against non-blood borne antigens and recognizing E by molecular mimicry are far less skewed, possibly explaining why the presence of this antibody rarely has clinical consequences. The less pronounced skewing of glycosylation of anti-c might also explain the lower risk of severe HDFN mediated compared to anti-D. Anti-K glycosylation influenced clinical outcome, but in contrast to anti-Rh antibodies, it was not fucosylation but galactosylation and sialylation that correlated with anaemia. This might be related to the differences in the mechanism by which these antibodies induce anemia. Importantly, the clinical outcome of HDFN is strongly affected by IgG1-glycosylation, which is proving to become an important biomarker in screening for severe cases of HDFN. Disclosures No relevant conflicts of interest to declare.

Lupus Anticoagulant-hypoprothrombinemia Syndrome that did not Progress to Systemic Lupus Erythematosus: A Case Report

Lupus anticoagulant-hypoprothrombinemia syndrome (LA-HPS) is a rare disorder, and appears mostly in children. The primary concern is its potential development into systemic lupus erythematosus (SLE). A 5-year-old patient was hospitalized with multiple purpuric lesions. A markedly prolonged prothrombin time and activated partial thromboplastin time were observed and were not corrected after mixing with normal plasma. Decreased factor II activity was consistent with LA-HPS. Identifying risk factors that play an important role in the development of SLE in patients with LA-HPS is of importance. Based on the case described here, anti-double stranded (ds) DNA antibody and the Sapporo criteria for antiphospholipid syndrome are related to subsequent SLE development, whereas there is no correlation with the results of the lupus anticoagulant (LA) test. We recommend an early and serial examination of anti-ds DNA antibody and full evaluation of Sapporo criteria for the screening of patients with LA-HPS who may progress to SLE.

Anti-D administration in pregnancy for preventing Rhesus alloimmunisation.

During pregnancy, a Rhesus negative (Rh-negative) woman may develop antibodies when her fetus is Rhesus positive (Rh-positive). These antibodies may harm Rh-positive babies. To assess the effects of antenatal anti-D immunoglobulin on the incidence of Rhesus D alloimmunisation when given to Rh-negative women without anti-D antibodies. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2015) and reference lists of retrieved studies. Randomised trials in Rh-negative women without anti-D antibodies given anti-D after 28 weeks of pregnancy, compared with no treatment, placebo or a different regimen of anti-D. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We included two trials involving over 4500 women, comparing anti-D prophylaxis with no anti-D during pregnancy in this review. Overall, the trials were judged to be at moderate to high risk of bias. The quality of the evidence for pre-specified outcomes was also assessed using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach.In regards to primary review outcomes, there did not appear to be a clear difference in the risks of immunisation when women who received anti-D at 28 and 34 weeks' gestation were compared with women who were not given antenatal anti-D: risk ratio (RR) for incidence of Rhesus D alloimmunisation during pregnancy was 0.42 (95% confidence interval (CI) 0.15 to 1.17, two trials, 3902 women; GRADE: low quality evidence); at birth of a Rh-positive infant the RR was 0.42 (95% CI 0.15 to 1.17, two trials, 2297 women); and within 12 months after birth of a Rh-positive infant the average RR was 0.39 (95% CI 0.10 to 1.62, two trials, 2048 women; Tau²: 0.47; I²: 39%; GRADE: low quality evidence). Neither of the trials reported on incidence of Rhesus D alloimmunisation in subsequent pregnancies.Considering secondary outcomes, in one trial, women receiving anti-D during pregnancy were shown to be less likely to register a positive Kleihauer test (which detects fetal cells in maternal blood) in pregnancy (at 32 to 25 weeks) (RR 0.60, 95% CI 0.41 to 0.88; 1884 women; GRADE: low quality evidence) and at the birth of a Rh-positive infant (RR 0.60, 95% CI 0.46 to 0.79; 1189 women; GRADE: low quality evidence). No clear differences were seen for neonatal jaundice (RR 0.26, 95% CI 0.03 to 2.30; 1882 infants; GRADE: very low quality evidence). Neither of the trials reported on adverse effects associated with anti-D treatment. Existing studies do not provide conclusive evidence that the use of anti-D during pregnancy benefits either mother or baby in terms of incidence of Rhesus D alloimmunisation during the pregnancy or postpartum, or the incidence of neonatal morbidity (jaundice) (low to very low quality evidence). However women receiving anti-D may be less likely to register a positive Kleihauer test in pregnancy and at the birth of a Rh-positive infant (low quality evidence). Fewer women who receive anti-D during pregnancy may have Rhesus D antibodies in a subsequent pregnancy, with benefits for the baby, however this needs to be tested in studies of robust design.

DRUG-INDUCED LUPUS CAUSED BY LONG TERM MINOCYCLINE TREATMENT FOR ACNE VULGARIS

An 18-year-old Japanese girl had received oral minocycline 200mg daily for treatment of acne vulgaris since 16 years old. She had a fever three months before admission, followed by joint pains in her knees, elbows and several proximal interphalangeal joints one month before admission. She was referred to our hospital because of a high serum level of anti-DNA antibody. She had already discontinued oral minocycline five weeks before admission, because she missed her medication refilled. On admission, the arthralgia and fever spontaneously resolved, and there were no laboratory evidence of hypocomplementemia and cytopenia. She had neither erythema nor internal organ involvements. Because her symptoms subsided spontaneously after the cessation of minocycline, she was considered to have drug-induced lupus. Both the arthralgia and fever did not relapse, and anti-ds DNA antibody returned to normal during a follow-up period without treatment. There are few reports of drug-induced lupus caused by minocycline in Japan. This case highlights the importance of considering minocycline-induced lupus.

Differential Expression of Specific Dermatan Sulfate Domains in Renal Pathology.

Dermatan sulfate (DS), also known as chondroitin sulfate (CS)-B, is a member of the linear polysaccharides called glycosaminoglycans (GAGs). The expression of CS/DS and DS proteoglycans is increased in several fibrotic renal diseases, including interstitial fibrosis, diabetic nephropathy, mesangial sclerosis and nephrosclerosis. Little, however, is known about structural alterations in DS in renal diseases. The aim of this study was to evaluate the renal expression of two different DS domains in renal transplant rejection and glomerular pathologies. DS expression was evaluated in normal renal tissue and in kidney biopsies obtained from patients with acute interstitial or vascular renal allograft rejection, patients with interstitial fibrosis and tubular atrophy (IF/TA), and from patients with focal segmental glomerulosclerosis (FSGS), membranous glomerulopathy (MGP) or systemic lupus erythematosus (SLE), using our unique specific anti-DS antibodies LKN1 and GD3A12. Expression of the 4/2,4-di-O-sulfated DS domain recognized by antibody LKN1 was decreased in the interstitium of transplant kidneys with IF/TA, which was accompanied by an increased expression of type I collagen, decorin and transforming growth factor beta (TGF-β), while its expression was increased in the interstitium in FSGS, MGP and SLE. Importantly, all patients showed glomerular LKN1 staining in contrast to the controls. Expression of the IdoA-Gal-NAc4SDS domain recognized by GD3A12 was similar in controls and patients. Our data suggest a role for the DS domain recognized by antibody LKN1 in renal diseases with early fibrosis. Further research is required to delineate the exact role of different DS domains in renal fibrosis.

Correlation between the Amount of Anti-D Antibodies and IgG Subclasses with Severity of Haemolytic Disease of Foetus and Newborn.

AIM:The aim of this study was to investigate the influence of subclasses to IgG anti-D on the intensity of hemolytic disease of fetus and newborn (HDFN) at 45 fetuses/newborns with symptoms of mild and severe HDFN in Republic of Macedonia.MATERIAL AND METHODS:In retrospective and prospective studies, in a period of 10 years, from 2004 to 2014, there have been immunohemathology tests performed on 22 009 samples on serums of pregnant women.RESULTS:At 37.78% of the total number of tested patients, IgG1 and IgG3 was the reason for severe HDFN. At 17.77% of the total number of tested patients, which had only IgG1detected, was the reason for serious intensity of HDFN. The correlation of the titer to anti-D antibodies in the mother’s serum and the intensity of HDFN were researched in 48 newborns. The titers between 1:8 and 1:32 resulted in 3 cases of HDFN with symptoms of severe disease and in 4 cases there were no signs of HDFN. At 12 women that had a titre between 1:32 and 1:512, five of the newborns developed severe HDFN, and seven had symptoms of mild and weak intensity form. In 3 cases the titer was higher than 512, and out of them one newborn had weak symptoms of HDFN, one developed severe HDFN and one ended with foetal death. Only in one case the titer reached a value higher than 1000, and it ended with a fetal death.CONCLUSIONS:The titers of the pregnant women serum those are lower than 32 and those higher than 1000 can well predict HDFN. The titers of anti-D antibodies between 64 and 512 have no exact predictive value. IgG1 and IgG3 subclasses of anti-D have no predictive value by themselves, and cannot foresee the outcome of HDFN. The research study results suggest that IgG1 and IgG3 should be included in a multi – parameter protocol for evaluation of the HDFN intensity. They can give a real assessment of the expected HDFN intensity in combination with the titer hight and the significance of the antibodies.

Preliminary analysis of the contributions of major histocompatibility complex-H2 to autoantibody production in a murine model of systemic lupus erythematosus. (BA3P.116)

Abstract The stochastic and heterogeneous nature of Systemic Lupus Erythematosus (SLE) supports a model whereby multiple genetic and/or environmental hits culminate in loss of tolerance and autoantibody production. Consistent with this model, the phenotype of CD45E613R mice that contain a single point mutation in the juxtamembrane wedge of CD45 depends on genetic context. Despite similar dysregulated phosphatase activity in all immune cells, CD45E613R mice on a C57Bl/6 (B6) background have no overt phenotype while BALB/c (BA) mice develop anti-double stranded (ds) DNA antibodies. An unbiased genome-wide screen for modifiers of autoantibody production between CD45E613R B6 and BA mice identified two candidate loci: Wedge Associated Modifier (Wam) 1 on Chromosome (Chr) 9 encompassing tlr9 and Wam2 on Chr 17 encompassing MHC H2. Previous work has shown that the hyporesponsive BA TLR9 allele permits anti-ds DNA antibodies while the B6 TLR9 allele is resistant. Here, we analyze the contribution of the MHC to this phenotype. CD45E613R BALB/c mice congenic for the B6 H2 locus develop anti-Sm antibodies while B6 mice congenic for the BALB/c H2 locus develop anti-Sm and anti-dsDNA antibodies. H2 congenic CD45E613R BALB/c mice have increased transitional B cells and a trend in increased B1 cells compared to congenic B6 mice. Thus, we hypothesize that MHC influences autoantibody specificity.

Passenger lymphocyte syndrome in ABO and Rhesus D minor mismatched liver and kidney transplantation: A prospective analysis

The increasing demand for solid organs has necessitated the use of ABO and Rhesus (Rh) D minor mismatched transplants. The passenger lymphocyte syndrome (PLS) occurs when donor lymphocytes produce antibodies that react with host red blood cell (RBC) antigens and result in hemolysis. Our aim was to evaluate prospectively the role of PLS in post transplant anemia and hemolysis in ABO and RhD minor mismatched recipients of liver and kidney grafts and to study the association of PLS with donor lymphocyte microchimerism. We examined 11 liver and 10 kidney recipients at Day +15 for anemia, markers of hemolysis, direct antiglobulin test and eluates, and serum RBC antibodies. Microchimerism was determined in peripheral blood lymphocytes by genotyping of simple sequence length polymorphisms encoding short tandem repeats. Immune hemolytic anemia and anti-recipient RBC antibodies were observed in 2 out of 11 liver (18.2%) and 2 out of 10 kidney (20%) transplants. RBC antibody specificity reflected the donor to recipient transplant, with anti-blood group B antibodies identified in 2 cases of O to B and 1 case of A to AB transplants while anti-D antibodies were detected in 1 case of RhD-negative to RhD-positive transplant. Donor microchimerism was found in only 1 patient. In conclusion, passenger lymphocyte mediated hemolysis is frequent in minor mismatched liver and kidney transplantation. Recognizing PLS as a potential cause of post transplant anemia may allow for early diagnosis and management to decrease the morbidity and mortality in some patients.

RhD Immunization Despite Adequate Immunoprophylaxis: Role of Fc Gamma Receptor Gene Polymorphisms

▪Introduction: One of the most effective immunological interventions in clinical medicine is the prevention of hemolytic disease of the newborn by prophylactic Rh immune globulin (Rh-Ig) therapy. The administration of ante- and postnatal Rh-Ig has reduced the risk of RhD immunization in the Netherlands from 17% to a mere 0.31%, yet its mechanism of action is still unknown. To gain more insight into the possible working mechanism of the Rh-Ig prophylaxis we analyzed potential risk factors and genotyped all known IgG-Fc receptor (protein FcγR, gene FCGR) variants known to date, on a cohort of Dutch women who failed Rh-Ig prophylaxis and developed anti-D antibodies. Adequate Rh-Ig immunoprophylaxis was defined as an antenatal and postnatal prophylaxis of 1,000 IU (200 µg) in both current and previous pregnancies, according to the Dutch guidelines.Material and Methods: Between 1999 and 2013 we identified 274 women who produced anti-D antibodies. Through a structured questionnaire we collected information about Rh-Ig prophylaxis and additional clinical data for potential risk factors. In 122 cases, adequate Rh-Ig prophylaxis was given, and clinical risk factors for fetal maternal hemorrhage (FMH) could be collected. Their clinical circumstances were compared to a control group of 339 randomly selected pregnant women. The Rh-Ig therapy failure of 57 of those women could not be explained through our risk factor analysis. From these 57 cases, DNA was obtained, and used for the FcγR-specific multiplex ligation-dependent probe amplification (MLPA) assay, identifying both single nucleotide polymorphisms and copy number variations in the FCGR locus. The results were compared to a control group of 200 healthy donors.Results: A history of red blood cell transfusion (p=0.05) and caesarean section (p<0.0001) were identified to be independent risk factors for RhD immunization. All other described risk factors for FMH such as miscarriage, termination of pregnancy, or invasive diagnostic procedures, requiring an additional Rh-Ig dose according to the guidelines, were not found to increase the risk of immunoprophylaxis failure. RhD-immunization due to caesarian section or red blood cell transfusion accounted for 53% of our cohort, suggesting an alternative explanation for the production of Rh-Ig alloantibodies in the remaining 47% of the cases - despite adequate amount of prophylaxis given in current and previous pregnancies. We therefore postulate the existence of a genetic variation that puts women at increased risk for RhD immunization during pregnancy. To test this hypothesis we analyzed the genetic variation in the FCGR locus and found a significantly (p=0.02) increased prevalence of the FCGR2 -ORF, expressing a functional copy of the activating FcγRIIc, which is otherwise a pseudogene. Strikingly, the prevalence of the 2B.4-promotor haplotype of the FCGR2B gene, associated with a 1.5 fold increase of the inhibitory FcγRIIb, was strongly (p=0.0001) increased.Conclusion: Caesarian section and red blood cell transfusion are risk factors that increase RhD immunization during pregnancies, accounting for about half failed Rh-Ig prophylactic cases. Genetic variation in the FCGR-gene might be a possible explanation for increased immunization risk. In our cohort we encountered a significantly increased frequency of individuals expressing FcγRIIc, along with a polymorphism encoding for a higher expression of the inhibitory receptor FcγRIIb, suggesting these genes to influence immune responses to RBC in a manner previously unrecognized. DisclosuresNo relevant conflicts of interest to declare.

Reassessing critical maternal antibody threshold in RhD alloimmunization: a 16-year retrospective cohort study

To determine the critical maternal antibody threshold for specialist referral in cases of RhD alloimmunization. This was a retrospective cohort study, covering a 16-year period at the national tertiary fetal medicine center for management of alloimmunization. Data concerning RhD alloimmunized pregnant women were extracted from an institutional database and maternal anti-D antibody levels were cross-checked with the national reference laboratory. Fetal hemoglobin (Hb) levels were determined only at the first intrauterine transfusion (IUT) and were compared with the pretransfusion maternal anti-D antibody level (IU/mL). Sensitivity, specificity and positive and negative predictive values of maternal antibody thresholds for detecting moderate to severe (Hb ≤ 0.64MoM) fetal anemia were calculated. Between 1996 and 2011, 66 women underwent a first IUT for RhD alloimmunization at our institution. The highest serum anti-D antibody level was extracted for 208 RhD alloimmunized women who did not require IUT during the last 10 years of the study period. The traditional maternal antibody threshold of > 15 IU/mL failed to detect 20% of cases of moderate to severe fetal anemia. The ≥ 4 IU/mL threshold had 100% sensitivity but a 45% false-positive rate. The optimal anti-D antibody threshold for specialist referral in our population was ≥ 6 IU/mL; at this level, no case of moderate to severe anemia was missed and specificity was 61%. Use of this threshold would have eliminated 10% of referrals to our fetal medicine unit without compromising fetal outcomes. Setting the critical maternal RhD antibody level at >15 IU/mL does not provide sufficient sensitivity. The lower threshold of ≥ 4 IU/mL, though sensitive, is associated with a 45% false-positive rate. In our population, a threshold of ≥ 6 IU/mL minimizes false-positive referrals while maintaining 100% sensitivity for moderate to severe fetal anemia.

Clinical and laboratory update on the DEL variant.

Serological assays for the RhD blood group are based on detection of the RhD antigen on human red blood cells using a specific anti-D antibody. The weak expression of the RhD antigen in the DEL variant hinders the sensitivity of conventional serological assays. Evidence of anti-D immunization in patients with D-negativity who have received DEL-variant blood units has been reported in various populations. This observation has prompted the need for genetic epidemiological and clinical data on the DEL variant in the development of DEL molecular diagnostic testing. This review highlights the molecular features of the DEL variant, the clinical consequences of DEL-blood transfusion, and current approaches for detection of the DEL-variant for donor screening and transfusion.