Circulating bioactive bacterial DNA is associated with immune activation and complications in common variable immunodeficiency.

Common variable immunodeficiency (CVID) is characterized by profound primary antibody defects and frequent infections, yet autoimmune/inflammatory complications of unclear origin occur in 50% of individuals and lead to increased mortality. Here, we show that circulating bacterial 16S rDNA belonging to gut commensals was significantly increased in CVID serum (P < 0.0001), especially in patients with inflammatory manifestations (P = 0.0007). Levels of serum bacterial DNA were associated with parameters of systemic immune activation, increased serum IFN-γ, and the lowest numbers of isotype-switched memory B cells. Bacterial DNA was bioactive in vitro and induced robust host IFN-γ responses, especially among patients with CVID with inflammatory manifestations. Patients with X-linked agammaglobulinemia (Bruton tyrosine kinase [BTK] deficiency) also had increased circulating bacterial 16S rDNA but did not exhibit prominent immune activation, suggesting that BTK may be a host modifier, dampening immune responses to microbial translocation. These data reveal a mechanism for chronic immune activation in CVID and potential therapeutic strategies to modify the clinical outcomes of this disease.

Resolution of serologic problems due to cold agglutinin mediated autoimmune hemolytic anemia and its transfusion decision.

BACKGROUND: Autoimmune hemolytic anemia (AIHA) is a rare disease characterized by hemolysis caused by autoantibodies against erythrocyte surface antigen. These antibodies can be classified as warm, cold, or mixed types. METHODS: We report two cases of cold agglutinin disease (CAD), which were eventually diagnosed owing to blood group discrepancy. Resolution was achieved after washing the red blood cells (RBCs) with warm saline and absorbing the autoantibodies at 4°C with the washed RBCs. We also assessed the patient's condition and discussed the strategy of blood transfusion. RESULTS: The first case occurred after postoperative chemotherapy for rectal cancer, and the other manifested with anemia from the outset. Direct antiglobulin tests were positive and revealed autoantibodies against C3d only. Cold agglutinin titration was performed, and the titers of both were 1:1024. Eventually, the patient's condition stabilized without blood transfusion. CONCLUSION: The serological discrepancies observed in the blood transfusion department can successfully guide blood transfusion decisions in cases of CAD.

Serologic characteristics of oxaliplatin antibodies in 15 patients with drug-induced immune hemolytic anemia.

BACKGROUND: Oxaliplatin, a third-generation platinum derivative is commonly used in combination treatment of metastatic colorectal cancer. Since 2008, it is the second most common cause of drug-induced immune hemolytic anemia (DIIHA) investigated in our laboratory. STUDY DESIGN AND METHODS: Samples from fifteen patients including nine (60%) with intravascular hemolysis, suspected of having DIIHA were studied for the presence of anti-oxaliplatin. Direct antiglobulin tests (DATs) and tests with oxaliplatin-treated red blood cells (RBCs) or untreated and enzyme-treated RBCs in the presence of oxaliplatin were performed. A pool of normal AB sera with no unexpected antibodies was used as a control for nonimmunologic protein adsorption (NIPA). RESULTS: Eleven (73%) of the fifteen patients had antibodies to oxaliplatin that reacted with drug-treated RBCs and untreated RBCs in the presence of drug by tube and/or gel method. Lower-titer reactivity (<20) obtained with four patients' sera and the corresponding pooled normal sera was most likely due to NIPA. Eighty seven percent (13/15) of the patients had positive DAT either with anti-IgG only (33%), IgG + C3d (40%), or C3d only (13%). Two patients had a negative DAT. No directly agglutinating antibody was observed with the pools of normal donor's sera in the presence of oxaliplatin. CONCLUSION: Anti-oxaliplatin can cause severe intravascular hemolysis. Complement can usually be detected on the patient's RBCs and anti-oxaliplatin can be detected in the patient's serum. RBC-bound albumin detection with anti-human albumin needs to be performed to confirm NIPA which could have contributed to the patient's hemolytic anemia.

Late-onset myocardial infarction and autoimmune haemolytic anaemia in a COVID-19 patient without respiratory symptoms, concomitant with a paradoxical increase in inflammatory markers: a case report.

BACKGROUND: In December 2019, a new coronavirus (named severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) spread from China, causing a pandemic in a very short time. The main clinical presentation of SARS-CoV-2 infection (COVID-19, coronavirus disease-2019) is pneumonia, but several cardiovascular complications may also occur (e.g., acute coronary syndromes, pulmonary embolism, stroke, arrhythmias, heart failure and cardiogenic shock). Direct or indirect mechanisms induced by SARS-CoV-2 could be implicated in the pathogenesis of these events. CASE PRESENTATION: We report herein the third case of COVID-19 autoimmune haemolytic anaemia (AIHA) reported so far, which occurredwithout any other possible explanations in a Caucasian patient. The patient also suffered from ST-elevation myocardial injury. CONCLUSIONS: Both complications occurred quite late after COVID-19 diagnosis and were probably precipitated by systemic inflammation, as indicated by a significant delayed increase in inflammatory markers, including interleukin-6 (IL-6).

Silent red blood cell autoantibodies: Are they naturally occurring or an effect of tolerance loss for a subsequent autoimmune process?

Unexpected anti-red blood cell (RBC) alloantibodies are routinely investigated in immunohematology and blood banking since their existence in pregnant women may induce haemolytic disease of the foetus and newborn, and their presence in donors may induce haemolytic transfusion reactions or hyperacute rejection in solid organ transplantation. Unexpected anti-RBC alloantibodies may target antigens of the most blood types excluding the expected antibodies targeting the ABO antigens. Their incidence in humans was originally linked to alloimmunization events such as blood transfusions, transplants, or pregnancies. But later, many findings revealed their existence in pathogenic processes such as malignancies, infections, and autoimmune diseases; and usually (but not always) associated to autoimmune haemolytic anaemia (AIHA). Nevertheless, unexpected anti-RBC autoantibodies are also occasionally found in healthy individuals in the absence of AIHA and with no history of alloimmunization or the associated pathologic processes. Hence, they are generally known as non-clinically significant, are excluded for typification and called "silent red blood cell autoantibodies (SRBCAA)". This review highlights evidence related to genetic predisposition, molecular mimicry, immune dysregulation, and immune tolerance loss surrounding the existence of anti-RBC antibodies, describing the presence of SRBCAA as possible early witnesses of the development of autoimmune diseases.

The Changing Landscape of Autoimmune Hemolytic Anemia.

Autoimmune hemolytic anemia (AIHA) is a greatly heterogeneous disease due to autoantibodies directed against erythrocytes, with or without complement activation. The clinical picture ranges from mild/compensated to life-threatening anemia, depending on the antibody's thermal amplitude, isotype and ability to fix complement, as well as on bone marrow compensation. Since few years ago, steroids, immunesuppressants and splenectomy have been the mainstay of treatment. More recently, several target therapies are increasingly used in the clinical practice or are under development in clinical trials. This has led to the accumulation of refractory/relapsed cases that often represent a clinical challenge. Moreover, the availability of several drugs acting on the different pathophysiologic mechanisms of the disease pinpoints the need to harness therapy. In particular, it is advisable to define the best choice, sequence and/or combination of drugs during the different phases of the disease. In particular relapsed/refractory cases may resemble pre-myelodysplastic or bone marrow failure syndromes, suggesting a careful use of immunosuppressants, and vice versa advising bone marrow immunomodulating/stimulating agents. A peculiar setting is AIHA after autologous and allogeneic hematopoietic stem cell transplantation, which is increasingly reported. These cases are generally severe and refractory to standard therapy, and have high mortality. AIHAs may be primary/idiopathic or secondary to infections, autoimmune diseases, malignancies, particularly lymphoproliferative disorders, and drugs, further complicating their clinical picture and management. Regarding new drugs, the false positivity of the Coombs test (direct antiglobulin test, DAT) following daratumumab adds to the list of difficult diagnosis, together with the passenger lymphocyte syndrome after solid organ transplants. Diagnosis of DAT-negative AIHAs and evaluation of disease-related risk factors for relapse and mortality, notwithstanding improvement in diagnostic approach, are still an unmet need. Finally, AIHA is increasingly described following therapy of solid cancers with inhibitors of immune checkpoint molecules. On the whole, the double-edged sword of new pathogenetic insights and therapies has changed the landscape of AIHA, both providing enthusiastic knowledge and complicating the clinical management of this disease.

Tolerization of recent thymic emigrants is required to prevent RBC-specific autoimmunity.

Autoimmune hemolytic anemia (AIHA) leads to accelerated destruction of autologous red blood cells (RBCs) by autoantibodies. AIHA is a severe and sometimes fatal disease. While there are several therapeutic strategies available, there are currently no licensed treatments for AIHA and few therapeutics result in treatment-free durable remission. The etiology of primary AIHA is unknown; however, secondary AIHA occurs concurrently with lymphoproliferative disorders and infections. Additionally, AIHA is the second most common manifestation of primary immunodeficiency disorders and has been described as a side effect of checkpoint inhibitor therapy. Given the severity of AIHA and the lack of treatment options, understanding the initiation of autoimmunity is imperative. Herein, we utilized a well-described model of RBC biology to dissect how RBC-specific autoreactive T cells become educated against RBC autoantigens. We show that, unlike most autoantigens, T cells do not encounter RBC autoantigens in the thymus. Instead, when they leave the thymus as recent thymic emigrants (RTEs), they retain the ability to positively respond to RBC autoantigens; only after several weeks in circulation do RTEs become nonresponsive. Together, these data suggest that any disruption in this process would lead to breakdown of tolerance and initiation of autoimmunity. Thus, RTEs and this developmental process are potential targets to prevent and treat AIHA.

Systemic Lupus Erythematosus, Evans Syndrome, and Neurofibromatosis: An Unusual Combination in Pediatric Patient.

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organ systems. Patients can have hematologic manifestations, including Evans syndrome (ES), which is characterized by immune-mediated thrombocytopenia and anemia. The association of neurofibromatosis 1 (NF1) with autoimmune disorders is rarely reported. We will review the literature for this combination of disorders and describe a case of a 16-year-old girl who presents with immune-mediated cytopenias and is diagnosed with SLE, ES, and NF1. There are 7 reported cases of SLE and NF1 and only 2 are pediatric cases. There are no reports of the combination of SLE, ES, and NF1.

A Retrospective Study of the Combination of Rituximab, Cyclophosphamide and Dexamethasone for the Treatment of Relapsed/Refractory Warm Antibody Autoimmune Hemolytic Anemia.

The combination of rituximab, cyclophosphamide, and dexamethasone (RCD) is highly effective in the treatment of warm autoimmune hemolytic anemia (WAIHA) associated with chronic lymphocytic leukemia (CLL). We treated a cohort of patients with relapsed/refractory WAIHA, without CLL, with RCD. The primary objective was to evaluate the overall response (OR) of RCD therapy. Complete response (CR) was defined as a hemoglobin (Hgb) ≥12 g/dL. Partial response (PR) was defined as Hgb 10-11.9 g/dL or ≥2 g/dL increase in Hgb. Sustained response was defined as Hgb ≥10 g/dL with no treatment changes. A total of 16 patients with relapsed/refractory WAIHA received RCD (7 primary WAIHA, 9 secondary WAIHA) for a median of 4 cycles (range: 2-6). The median pretreatment Hgb was 10.0 g/dL (range: 4.3-12.2). The median best Hgb achieved was 12.5 g/dL (range: 10.6-15.1) with a median of 2 cycles until best Hgb response. The OR was 94% (11 CR, 4 PR). Two immunocompromised patients were admitted for infections during RCD treatment. There were no deaths during the treatment or follow-up period. Following a response to RCD, 4 patients received noncorticosteroid immune modulation therapy and 4 patients continued on corticosteroid therapy. Seven patients received no additional treatment.

Warm red blood cell autoantibodies and clinical diagnoses in patients with or without autoimmune hemolysis.

OBJECTIVES: Red blood cell autoantibodies (RBC autoAbs) of IgG class are found in the majority of patients with warm autoimmune hemolytic anemia (wAIHA) but sometimes also during the pretransfusion testing of patients with different diagnoses but without hemolysis. The aim of the study was to identify the main differences between these two groups of patients according to age, gender, subclass and titer of IgG RBC autoAbs and diagnosis. MATERIAL AND METHODS: In the 9-year retrospective study, data were collected from records of 291 patients with IgG RBC autoAbs detected by gel technique, from which 111 with wAIHA. RESULTS: More than 85% of patients in both groups were over 40 years old, with male to female ratio 1:1.9 in wAIHA vs 1:1.3 in patients without hemolysis (P=0.0916). The main characteristics of patients with wAIHA vs patients without hemolysis were: IgG only 38% vs 70%, IgG+Complement 62% vs 30%, total IgG1 79% vs 55%, IgG1+IgG3 35% vs 11%, titer of 100 for IgG1+IgG3 17% vs 3% (P<0.0001), respectively, while titer of 100 for IgG1 18% vs 9% (P=0.0241). The underlying diagnosis in wAIHA vs patients without hemolysis: hematologic disorders 41% vs 22% (P=0.0006), autoimmune disorders 12% vs 13% (P=0.8033), solid tumors 5% vs 14% (P=0.0154) and surgery procedures 6% vs 26% (P<0.0001). CONCLUSION: We observed more wAIHA patients with high titer of IgG1 and high prevalence of IgG1+IgG3 and consider that patients without hemolysis having identical results might be interesting to find out how they are protected from damage by RBC autoAbs.

Pembrolizumab-induced autoimmune haemolytic anaemia and cholangitis.

Increasing numbers of patients are now offered immunotherapy as part of their cancer treatment. These treatments, while often very effective, have a wide range of adverse effects that are distinct from those of traditional chemotherapy regimens. Thyroid disease, dermatological disease, colitis and pneumonitis are some of the most commonly reported immune side effects. We present a case of life-threatening de novo autoimmune haemolytic anaemia (AIHA) complicated by immune cholangitis induced by pembrolizumab. An 81-year-old woman with metastatic melanoma completed a two-year course of pembrolizumab in August 2018 and six weeks later presented to hospital with jaundice. Admission haemoglobin (Hb) was 91 g/L, rapidly decreasing to 31 g/L, at which point she required admission to the intensive care unit. AIHA is a rare but potentially life-threatening complication of checkpoint inhibitors and should be considered in patients presenting with anaemia during or after immunotherapy treatment.

Anti tissue transglutaminase antibody in idiopathic autoimmune haemolytic anemia.

BACKGROUND: In idiopathic autoimmune haemolytic anaemia (AIHA haemolytic antibodies are directed to every type of red cellsWestern blot studies have shown antibody positivity towards red cell anion channel complex which also includes band 4.2 a protein with similarities to tissue trans glutaminase. OBJECTIVE: Evaluation of AIHA for anti tissue transglutaminase antibody (Anti tTG). MATERIALS & METHODS: Twenty three AIHA patients were tested along with routine hamatogical work up, for a series of auto antibodies and red cell eluates and serum from the patents were tested against solubilised group O red cell ghosts on western blot. Other ancillary investigations were done to rule out complications and secondary causes of haemolysis. RESULTS: 11/23 patients (48%) were positive for anti tTG, Four, 3 and 8,7 patients were positive for anti thyroid, anti b2 glycoprotein, lupus anticoagulant and ANA respectively. One patient with anti tTG had biopsy proven celiac disease. Three patient developed DVT and all of them were lupus anticoagulant as well as b2 gp-1 antibody positive.17 had become Coombs test negative on treatment while 21/23 had positive western blot test. DISCUSSION & CONCLUSION: There is strong association of anti tTG antibody with idiopathic AIHA. Aetiological association of this finding needs exploration.