Antibodies to human neutrophil antigen HNA-3b implicated in cases of neonatal alloimmune neutropenia.

BACKGROUND: Neonatal alloimmune neutropenia results from maternal alloimmunization to human neutrophil antigens. The alloantibodies involved in neonatal alloimmune neutropenia are against human neutrophil antigens HNA-1a, HNA-1b, HNA-1c, HNA-1d, HNA-2, HNA-3a, HNA-4a, HNA-4b, and HNA-5a; however, to date, antibodies specific to HNA-3b have not been reported. STUDY DESIGN AND METHODS: Blood samples from 10,000 unselected neonates were analyzed, resulting in the selection of 88 neutropenic newborns (neutrophil count <1.5 × 109 /L) from 83 mothers (three pairs of twins and one triplet). HNA-3 genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism to identify the cases of maternal-fetal HNA-3 incompatibility. Serologic studies for detecting maternal HNA-3 alloantibodies were performed with the granulocyte agglutination test, the white blood cell immunofluorescence test, and a LABScreen Multi-HNA Kit. RESULTS: Genotyping studies identified 13 of 88 (14.8%) instances of maternal-fetal HNA-3 incompatibility, with all mothers typed as HNA-3a/a and neonates typed as HNA-3a/b. Serologic studies revealed that five of 13 (38.5%) mothers carried anti-HNA-3b plus human leukocyte antigen antibodies and that three of 13 (23.1%) mothers had anti-HNA-3b without human leukocyte antigen antibodies. CONCLUSION: Here, we report the first three cases of neonatal alloimmune neutropenia associated with HNA-3b antibodies resulting in a neonatal alloimmune neutropenia incidence of one in 3333 live births.

Down regulation of protective genes is associated with cellular and antibody-mediated rejection.

Despite advances in immunosuppressive therapy, rejection still remains the main obstacle to a successful transplant. This study aims to explore the gene expression profile of the rejection process in order to decrease the number of unnecessary endomyocardial biopsies in stable patients. METHODS: A total of 300 formalin-fixed and paraffin-embedded (FFPE) endomyocardial biopsies sampled from 63 heart allograft recipients were included in this study. Acute cellular rejection (ACR) and antibody-mediated rejection (AMR) were diagnosed by histological analysis and immunohistochemical C4d staining, respectively. Analysis of gene expression was performed by quantitative real-time polymerase chain reaction. The samples were grouped according to the ISHLT rejection classification, aiming the statistical analysis. RESULTS: There was a significant decrease in the HMOX1, AIF1, and CCL2 transcript over the post-transplantation period in non-rejection group (P<.001). Furthermore, the ADIPOR1, ADIPOR2, BCL2L1, and VEGFA protective genes were significantly downregulated in the ACR group (P<.05). ADIPOR2, BCL2L1, IL6, and NOS2 genes were also significantly downregulated in the AMR group than in the non-rejection group (P<.05). CONCLUSION: The downregulations of the protective genes contribute to the allograft rejection, and the archived FFPE samples are useful for the gene expression analysis aiming the allograft rejection surveillance.

Proteasome Inhibitor Carfilzomib-Based Therapy for Antibody-Mediated Rejection of the Pulmonary Allograft: Use and Short-Term Findings.

We present this observational study of lung transplant recipients (LTR) treated with carfilzomib (CFZ)-based therapy for antibody-mediated rejection (AMR) of the lung. Patients were considered responders to CFZ if complement-1q (C1q)-fixing ability of their immunodominant (ID) donor-specific anti-human leukocyte antibody (DSA) was suppressed after treatment. Treatment consisted of CFZ plus plasma exchange and immunoglobulins. Fourteen LTRs underwent CFZ for 20 ID DSA AMR. Ten (71.4%) of LTRs responded to CFZ. DSA IgG mean fluorescence intensity (MFI) fell from 7664 (IQR 3230-11 874) to 1878 (653-7791) after therapy (p = 0.001) and to 1400 (850-8287) 2 weeks later (p = 0.001). DSA C1q MFI fell from 3596 (IQR 714-14 405) to <30 after therapy (p = 0.01) and <30 2 weeks later (p = 0.02). Forced expiratory volume in 1s ( FEV1 ) fell from mean 2.11 L pre-AMR to 1.92 L at AMR (p = 0.04). FEV1 was unchanged after CFZ (1.91 L) and subsequently rose to a maximum of 2.13 L (p = 0.01). Mean forced expiratory flow during mid forced vital capacity (25-75) (FEF25-75 ) fell from mean 2.5 L pre-AMR to 1.95 L at AMR (p = 0.01). FEF25-75 rose after CFZ to 2.54 L and reached a maximum of 2.91 L (p = 0.01). Responders had less chronic lung allograft dysfunction or progression versus nonresponders (25% vs. 83%, p = 0.04). No deaths occurred within 120 days and 7 patients died post CFZ therapy of allograft failure. Larger prospective interventional studies are needed to further describe the benefit of CFZ-based therapy for pulmonary AMR.

Frequency of intron 1 and 22 inversions of Factor VIII gene in Mexican patients with severe hemophilia A.

Hemophilia A (HA) is one of the most common inherited bleeding disorders caused by FVIII gene mutations. Inversion of intron 22 (inv22) originates 50% of cases of severe HA and is a major risk factor for inhibitor development. Inversion of intron 1 (inv1) has been reported to occur in 2-3% of severe HA patients. We studied both inversions to determine their frequencies in Mexican patients with severe HA and to compare these data with other HA populations. The inv22 was evaluated as a risk factor for FVIII inhibitor development in severe HA patients. We studied 44 patients from 31 severe HA families for the detection of inv22 and 94 patients from 65 families to detect inv1. We used the subcycling long-distance PCR to detect inv22 and rapid PCR in duplex reactions to detect inv1. We found a frequency of 45% for the inv22 and no inv1-positive patients (0%). These frequencies were not statistically different from other populations, although haplotype analyses of FVIII gene and telomeric regions should be incorporated to explore population-specific variation of inv1 frequencies. Inv22-positive patients showed 1.88X higher risk for developing inhibitors with respect to patients carrying other severe mutations; however, this OR value was not significant. Our findings confirm inv22 as a hot-spot for severe HA and evidence the low frequency of inv1 in a Mexican population. The non-significant risk for developing inhibitors among inv22-positive patients agrees with the variety of genetic and non-genetic factors involved in such a complication.

Severe immune haemolysis in a group A recipient of a group O red blood cell unit.

Haemolysis caused by passive ABO antibodies is a rare transfusional complication. We report a case of severe haemolytic reaction in a 38-year-old man (blood group A) with lymphoma who had received one red blood cell (RBC) unit group O. After transfusion of 270 mL, the patient experienced fever, dyspnoea, chills and back pain. On the following morning he was icteric and pale. Haptoglobin was inferior to 5.8 mgdL(-1), haemoglobin was not increased and lactate dehydrogenase was elevated. Haemolysis was evident on observation of the patient's post-transfusion samples. The recipient's red cells developed a positive direct antiglobulin test and Lui elution showed anti-A coated the cells. Fresh donor serum had an anti-A titre of 1024, which was not reduced by treating the serum with dithiothreitol. Donor isoagglutinin screening has been determined by microplate automated analyser and showed titre higher than 100. Physicians should be aware of the risk of haemolysis associated with ABO-passive antibodies. There is generally no agreement justifying the isoagglutinin investigation prior to transfusion. However, automated quantitative isoagglutinin determination could be part of the modern donor testing process, mainly in blood banks where identical ABO group units (platelets or phenotyped RBCs) are not available owing to limited supply.

Transfusión del paciente con autoanticuerpos / Transfusion of the patient with auto-antibodies

La transfusión de sangre en pacientes con AHAI, al igual que transfusión de sangre a otros pacientes, debe realizarse con los mismos criterios de compatibilidad. La sangre a transfundirse debe ser del mismo tipo ABO y Rh y no debe tener antígenos correspondientes a la especificidad de aloanticuerpos CS que pudiera tener el paciente. En pacientes no transfundidos y sin historia de embarazo no es necesario investigar exhaustivamente la presencia de aloanticuerpos, ya que muy rara vez los tienen. En pacientes transfundidos o con historia de embarazos, la posibilidad de tener algún aloanticuerpo clínicamente significativo está en el orden de los 14 a 40 por ciento. En pacientes con AHAI por anticuerpo caliente se recomienda investigar esta posibilidad primero mediante las técnicas de autoabsorción. En lo posible se recomienda obtener suficiente sangre (50-100 ml) y guardarla para posibles autoabsorciones futuras. Una vez que el paciente recibe sangre, la autoabsorción deja de ser confiable y la mejor técnica resulta la absorción diferencial. En pacientes con el síndrome de aglutininas frías la gran mayoría de los casos se resuelven mediante la técnica de precalentamiento a 37ºC en solución salina. Una vez seleccionada la sangre negativa para los antígenos correspondientes a los aloanticuerpos CS se procedería a la transfusión de la misma, en cantidades mínimas necesarias según la clínica del pacientes. Todo esto con el objeto de aliviar/prevenir posibles disfunciones de órganos vitales secundarias a una insuficiencia en el transporte de oxígeno.

Transfusión del paciente con autoanticuerpos / Transfusion of the patient with auto-antibodies

La transfusión de sangre en pacientes con AHAI, al igual que transfusión de sangre a otros pacientes, debe realizarse con los mismos criterios de compatibilidad. La sangre a transfundirse debe ser del mismo tipo ABO y Rh y no debe tener antígenos correspondientes a la especificidad de aloanticuerpos CS que pudiera tener el paciente. En pacientes no transfundidos y sin historia de embarazo no es necesario investigar exhaustivamente la presencia de aloanticuerpos, ya que muy rara vez los tienen. En pacientes transfundidos o con historia de embarazos, la posibilidad de tener algún aloanticuerpo clínicamente significativo está en el orden de los 14 a 40 por ciento. En pacientes con AHAI por anticuerpo caliente se recomienda investigar esta posibilidad primero mediante las técnicas de autoabsorción. En lo posible se recomienda obtener suficiente sangre (50-100 ml) y guardarla para posibles autoabsorciones futuras. Una vez que el paciente recibe sangre, la autoabsorción deja de ser confiable y la mejor técnica resulta la absorción diferencial. En pacientes con el síndrome de aglutininas frías la gran mayoría de los casos se resuelven mediante la técnica de precalentamiento a 37ºC en solución salina. Una vez seleccionada la sangre negativa para los antígenos correspondientes a los aloanticuerpos CS se procedería a la transfusión de la misma, en cantidades mínimas necesarias según la clínica del pacientes. Todo esto con el objeto