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Late onset neutropenia (LON) related to rituximab or rituximab plus chemotherapy is defined as an unexplained absolute neutrophil count of ≤1.5 × 10 9 /L starting at least four weeks after the last rituximab administration. LON is infrequent and its pathophysiology remains unknown. There are no guidelines or consensus strategies for the optimal management of patients developing LON. The majority of the patients recover promptly with no specific treatment and only some cases need to be managed with granulocytic colony stimulating factor (G-CSF), usually with a rapid response. Here, we describe a 69-year-old patient with Waldenström's macroglobulinemia who presented a septic event in the context of severe LON after rituximab plus bendamustine. The diagnosed of agranulocytosis was established by bone marrow examination. Interestingly, anti-neutrophil antibodies bound to the patient's granulocytes were found suggesting an autoimmune mechanism. The patient did not respond to G-CSF but achieved a rapid response after high doses of intravenous immunoglobulins with full white blood cell recovery., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Diez-Feijóo, Rodríguez-Sevilla, Fernández-Rodríguez, Flores, Raya, Ferrer, Colomo and Salar.)

Aims: Antithyroid drug (ATD)-induced agranulocytosis is a life-threatening adverse drug reaction. Previous studies suggested that HLA genotypes may play an important role in ATD-induced agranulocytosis. To examine the associations between HLA genotypes and ATD-induced agranulocytosis, we conducted a systematic review and meta-analysis of pharmacogenomics studies., Methods: We searched the MEDLINE, Embase and CENTRAL databases on 16 June 2018 for case-control studies on the associations between HLA genotypes with ATD-induced agranulocytosis. The Newcastle-Ottawa scale was used to evaluate the risk of bias of included studies. We conducted random-effects model meta-analysis to obtain pooled odds ratios (ORs) with 95% confidence intervals (CIs) to determine the associations between HLA genotypes and ATD-induced agranulocytosis., Results: We included 5 studies with 142 ATD-induced agranulocytosis cases, 1529 matched ATD-tolerant controls and 5945 healthy controls. The risk of bias of included studies was generally low. ATD-induced agranulocytosis was associated with HLA-B*27:05 (OR 10.97; 95% CI 0.75-159.99), HLA-B*38:02 (OR 19.85; 95% CI 7.94-49.57) and HLA-DRB1*08:03 (OR 5.29; 95% CI 3.44-8.14). After excluding propylthiouracil, the associations of ATD-induced agranulocytosis with HLA-B*27:05 and HLA-B*38:02 were strengthened (OR being 20.61 (95% CI 5.21-81.58) and 40.59 (95% CI 13.24-124.47), respectively). The associations of ATD-induced agranulocytosis with HLA-B*27:05, HLA-B*38:02 and HLA-DRB1*08:03 remained significant when compared to population controls (OR being 7.37 (95% CI 3.86-14.07), 36.43 (95% CI 12.80-103.70) and 5.42 (95% CI 2.36-12.47), respectively). HLA-B*27:05, HLA-B*38:02, and HLA-DRB1*08:03 alleles were associated with ATD-induced agranulocytosis, especially in carbimazole/methimazole-induced agranulocytosis., Conclusions: HLA-B*27:05, HLA-B*38:02 and HLA-DRB1*08:03 alleles were associated with ATD-induced agranulocytosis, especially in carbimazole/methimazole-induced agranulocytosis., (© 2019 The British Pharmacological Society.)

Mycoplasma pneumoniae is a common respiratory pathogen which may cause haematological manifestations including haemolytic anaemia and thrombocytopaenia. Severe neutropaenia is rare with very few cases reported in the literature. An 85-year-old man was transferred to our facility with agranulocytosis in the context of an infective exacerbation of chronic obstructive pulmonary disease with positive serological testing for M. pneumoniae. No alternative infective, autoimmune or lymphoproliferative cause of the neutropaenia was identified. Granulocyte autoantibody testing was performed with a positive result for neutrophil-bound IgG and IgM autoantibodies and significant agglutination reactions. The patient was treated with azithromycin and granulocyte colony-stimulating factor which resulted in a sustained resolution of his neutropaenia., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Purpose of Review: Clozapine-induced agranulocytosis/granulocytopenia (CIAG) is an uncommon condition, but potentially fatal in consequences. The pathogenesis, despite multiple experiments, is not fully elucidated. The current theory suggests reactive oxygen species - nitrenium ion as the most important factor of CIAG. In this review, mechanism and monitoring of CIAG will be discussed., Recent Findings: The mechanism of CIAG seems to have an autoimmune background, rather than toxic. Clozapine has a high potential to undergo biochemical activation to nitrenium ion. The role of the primary metabolite of clozapine - N-desmethylclozapine - is in decline. Nitrenium ion is mainly synthesized by CYP3A4, CYP2D6, and myeloperoxidase system in leukocytes. An important component of CIAG pathogenesis is genetic aberration in human leukocyte antigen genes, and also genes associated with apoptosis and ubiquitination. Clozapine monitoring regimes differ between countries. US-derived clozapine Risk Evaluation and Mitigation Strategy is the most tolerant in the aspect of blood parameter thresholds. Therefore, it provides the opportunities for physician to continue the treatment and also to rechallenge the drug after the episode of CIAG., Summary: Each patient with the episode of CIAG should be assessed individually, with special attention to risk factors and drug-drug interactions. Upon that, the decision about clozapine rechallenge or withdrawal should be made.

Although anti-neutrophil antibodies (ANAs) often exist and immunoreaction may be involved in agranulocytosis, few reports have so far described ANA-positive cases of agranulocytosis with an unknown etiology. We herein describe the case of a 69-year-old woman who presented with ANA-positive agranulocytosis. In this case, both the withdrawal of the drugs that had possibly caused neutropenia and the use of granulocyte-colony stimulating factor (G-CSF) were ineffective treatment measures. Approximately 2 weeks after the discontinuation of the suspected drugs, we initiated corticosteroid pulse therapy; the neutrophil count recovered by day 19 of steroid therapy. High-dose methylprednisolone therapy should thus be considered for patients demonstrating ANA-positive agranulocytosis with an unknown etiology that is refractory to G-CSF treatment.

Use of the atypical antipsychotic clozapine (CZP) is compromised by the risk of potentially fatal agranulocytosis/granulocytopenia (CIAG). To address this, we have established a simple, personalized cell culture-based strategy to identify CIAG-susceptible patients, hypothesizing that an immunogenic and possibly haptene-based mechanism underlies CIAG pathophysiology. To detect a putative haptene-induced response to CZP in vitro exposure, a traditional lymphocyte stimulation assay was adapted and applied to patient-specific peripheral blood-derived mononuclear cells (PBMC). 6 patients with a history of CIAG, 6 patients under CZP treatment (without CIAG) and 12 matched healthy controls were studied. In vitro CZP exposure, even at strikingly low levels, resulted in significantly increased proliferation rates only in CIAG patients' PBMC. Other parameters including cell viability and mitogen-induced proliferation were also affected by in vitro CZP exposure, yet there was no significant difference between the groups. This personalized approach is a starting point for further investigations into a putative haptene-based mechanism underlying CIAG development, and may facilitate the future development of predictive testing., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease that presents with sicca symptoms of the main mucosal surfaces. Patients with pSS have a broad spectrum of laboratory features, such as cytopenias and hypergammaglobulinemia. Although hematological abnormalities are usually seen in pSS patients, agranulocytosis and autoimmune hemolytic anemia (AIHA) are rare. Here we describe a 40-year-old woman with pSS who developed both agranulocytosis and mixed-type AIHA. An increased risk of malignancies has also been reported in pSS patients with hematological changes. Although there is no evidence of malignancies, this patient should be closely followed up in case of developing lymphoma., (© 2015 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.)

Amodiaquine (AQ) is associated with a relatively high incidence of idiosyncratic drug-induced liver injury (IDILI) and agranulocytosis. A previous study reported that a combination of high dose AQ and glutathione (GSH) depletion led to liver injury. However, the characteristics of this toxicity were very different from AQ-induced liver injury in humans. We developed a model of AQ-induced liver injury with characteristics similar to the injury in humans by treating mice with lower doses of AQ for several weeks. In this study we found that not only did GSH depletion not increase AQ covalent binding to hepatic proteins at this lower dose, but also it paradoxically prevented the liver injury. We extended the model to rats and found AQ treatment led to a mild delayed onset liver injury that resolved despite continued treatment with AQ. Immunohistochemistry indicated the presence of Kupffer cell activation, apoptosis and hepatocyte proliferation in the liver. There was also an increase in serum IL-2, IL-5, IL-9, IL-12, MCP-1 and TGFβ, but a decrease in leptin. Coincident with the elevated serum ALT, the number of liver CD4(+) T-cells, IL-17 secreting cells and TH17/Treg cells increased at Week 3 and decreased during continued treatment. Increases in NK1.1+ cells and activated M2 macrophages were also observed during liver injury. These results suggest that the outcome of the liver injury was determined by the balance between effector and regulatory cells. Co-treatment with cyclosporin prevented AQ-induced liver injury, which supports an immune mechanism. Retinoic acid (RA), which has been reported to enhance natural killer (NK) cell activity, exacerbated AQ-induced liver injury. These results suggest that AQ-induced IDILI is immune mediated and the subsequent adaptation appears to represent immune tolerance.

Good's syndrome is an immunodeficiency disease involving thymoma accompanied by hypogammaglobulinemia. We encountered a case of Good's syndrome accompanied by agranulocytosis that followed a rapid clinical course. A 72-year-old man visited our hospital with a two-week history of a sore throat. Candida albicans was detected in the pharynx, and hypogammaglobulinemia was detected in addition to granulocytopenia. The patient subsequently developed septic shock and followed a rapid clinical course which ended in death. Good's syndrome with agranulocytosis was diagnosed at autopsy. Good's syndrome accompanied by agranulocytosis can follow a rapid clinical course and some cases remain asymptomatic until old age. Its prompt treatment is crucial.

Antithyroid medications such as methimazole and propylthiouracil are commonly used to treat hyperthyroid disorders. Thionamide-induced agranulocytosis is a rare but life-threatening potential side effect of these medicines. In addition to routine monitoring of blood counts, healthcare workers caring for patients on such medication need to be mindful of atypical presentations of acute agranulocytosis throughout the treatment course. The manifestations of underlying infectious aetiologies can be mistaken for more common illness and result in delayed diagnosis. We present a case of a 41-year-old woman receiving methimazole for Grave's disease, who presented to outpatient care with high fever, pharyngitis, lymphadenopathy and jaundice. After failing to respond to empiric antibiotics, a diagnosis of neutropenia was made and the patient was admitted for inpatient care with eventual recovery following a course of granulocyte colony-stimulating factor. A diagnosis of atypical Bartonella henselae was eventually made and treated appropriately. The patient was later discharged and underwent radioactive iodine ablation., (2015 BMJ Publishing Group Ltd.)

Amodiaquine (AQ) treatment is associated with a high incidence of idiosyncratic drug-induced liver injury (IDILI) and agranulocytosis. Evidence suggests that AQ-induced IDILI is immune mediated. A significant impediment to mechanistic studies of IDILI is the lack of valid animal models. This study reports the first animal model of IDILI with characteristics similar to mild IDILI in humans. Treatment of female C57BL/6 mice with AQ led to liver injury with delayed onset, which resolved despite continued treatment. Covalent binding of AQ was detected in the liver, which was greater in female than in male mice, and higher in the liver than in other organs. Covalent binding in the liver was maximal by Day 3, which did not explain the delayed onset of alanine aminotransferase (ALT) elevation. However, coincident with the elevated serum ALT, infiltration of liver and splenic mononuclear cells and activation of CD8 T-cells within the liver were identified. By Week 7, when ALT levels had returned close to normal, down-regulation of several inflammatory cytokines and up-regulation of PD-1 on T-cells suggested induction of immune tolerance. Treatment of Rag1(-/-) mice with AQ resulted in higher ALT activities than C57BL/6 mice, which suggested that the adaptive immune response was responsible for immune tolerance. In contrast, depletion of NK cells significantly attenuated the increase in ALT, which implied a role for NK cells in mild AQ-induced IDILI. This is the first example of a delayed-onset animal model of IDILI that appears to be immune-mediated.

Introduction: Idiosyncratic drug-induced agranulocytosis (IDIAG) is a life-threatening adverse reaction characterized by an absolute neutrophil count < 500 cells/μl of blood. It shares many of the characteristics of other idiosyncratic drug reactions (IDRs), and this presumably reflects mechanistic similarities., Areas Covered: This review describes the evidence for mechanistic hypotheses of IDIAG and new hypotheses are explored., Expert Opinion: The characteristics of IDIAG are most consistent with an immune mechanism. Where genetic studies have been done, the genes associated with an increased risk of IDIAG are either human leukocyte antigen genes or other genes associated with the immune response, which provides further evidence for an immune mechanism. There is evidence that the immune response leading to most IDRs is triggered by reactive metabolites of the offending drug, and most drugs that are associated with IDIAG are either known to be oxidized to a reactive metabolite by neutrophils or have a functional group that has the potential to be easily oxidized to a reactive metabolite. There is new evidence that drugs that cause IDRs including IDIAG can activate inflammasomes. Thus, the ability of a drug to be oxidized to a reactive metabolite by neutrophils and to activate inflammasomes may be useful biomarkers to predict IDIAG risk.

Primary aromatic amine drugs are structural alerts in drug development because of their association with a high incidence of idiosyncratic drug reactions (IDRs). If biomarkers could be found that predict IDR risk, it would have a major impact on drug development. Previous attempts to do this through screening of hepatic gene expression profiles in rodents treated with aromatic amine drugs found limited changes. Of the drugs studied, aminoglutethimide (AMG) induced the most changes, and this led to a more comprehensive study of its effects on the liver. Brown Norway rats treated with AMG for up to 14 days showed only a transient elevation of glutamate dehydrogenase. Pathway-specific PCR arrays found few AMG-induced gene changes associated with an immune response and, of these changes, the majority were involved with innate immunity such as Tlr2, Ticam2, CD14, and C3. AMG treatment also led to significant changes in the apoptosis and mitochondrial panel of genes. It was recently found that AMG does induce significant changes in the bone marrow of rats, and agranulocytosis is a common IDR caused by AMG. In contrast, liver injury is not a common IDR associated with AMG. Therefore, the liver may be able to effectively deal with AMG reactive metabolites, and changes observed in this study may be involved in adaptation. Myeloperoxidase is also known to be able to oxidize aromatic amines to reactive metabolites, and these observations suggest that metabolism outside of the liver may be important for the mechanism of aromatic amine-induced IDRs.

Clozapine is a particularly effective antipsychotic medication but its use is curtailed by the risk of clozapine-induced agranulocytosis/granulocytopenia (CIAG), a severe adverse drug reaction occurring in up to 1% of treated individuals. Identifying genetic risk factors for CIAG could enable safer and more widespread use of clozapine. Here we perform the largest and most comprehensive genetic study of CIAG to date by interrogating 163 cases using genome-wide genotyping and whole-exome sequencing. We find that two loci in the major histocompatibility complex are independently associated with CIAG: a single amino acid in HLA-DQB1 (126Q) (P=4.7 × 10(-14), odds ratio (OR)=0.19, 95% confidence interval (CI)=0.12-0.29) and an amino acid change in the extracellular binding pocket of HLA-B (158T) (P=6.4 × 10(-10), OR=3.3, 95% CI=2.3-4.9). These associations dovetail with the roles of these genes in immunogenetic phenotypes and adverse drug responses for other medications, and provide insight into the pathophysiology of CIAG.

Background: Agranulocytosis is a rare but serious complication of antithyroid drug (ATD) therapy. Characteristics of agranulocytosis have been reported in only a small number of patients., Method: We studied 754 cases of ATD-induced agranulocytosis reported over 30 years. The age distribution and sex ratio were compared with those in 12 503 untreated Graves' patients at Kuma Hospital. The annual number of new Graves' patients in Japan was estimated from the Japan Medical Data Center Data Mart-Pharmacovigilance health insurance receipt database., Results: Agranulocytosis developed within 90 days after starting ATD therapy in most patients (84.5%). The methimazole dose given at onset was 25.2 ± 12.8 mg/d (mean ± SD). The mean age was 43.4 ± 15.2 years, and the male to female ratio was 1:6.3. When compared with patients at Kuma Hospital, patients with agranulocytosis were older (P < .001) and more females (P < .0001). Of 211 patients with more than 1 granulocyte measurement before onset, 131 (62%) showed normal counts (>1000/μL) within 2 weeks before onset, demonstrating real sudden onset of agranulocytosis. In contrast, some of the 20 patients with more than 4 measurements showed gradual decreases in granulocyte counts. Analysis of physician reports for 30 fatal cases revealed that some deaths might have been prevented. The number of new Graves' patients treated with ATD was estimated at about 35 000 per year, and the incidence rate of agranulocytosis was 0.1% to 0.15% in Japan., Conclusion: This is the largest study of agranulocytosis. Agranulocytosis tends to occur abruptly within 3 months after initiation of ATD therapy, although it develops gradually in some patients. Providing every patient with sufficient information on agranulocytosis is critical.

Antithyroid drugs as thionamides are largely used in the treatment of the thyrotoxicosis. Side effects were reported in less than 10% of the cases, especially hematological, hepatic or skin allergies. One of the most severe manifestations is agranulocytosis, probably based on an immune mechanism that is exacerbated by the presence of the thyroid autoimmune disease itself. If the presence of the severe leucopenia is actually an epiphenomenon of a preexisting hematological disturbance as multiple myeloma is debated. The myeloma may also be correlated with an autoimmune predisposition. We present the case of a 56 years old female patient diagnosed with Graves' disease, who developed agranulocytosis after 8 months of therapy with thiamazole. Two months after antithyroid drug's withdrawal, the granulocytes number increased and she received therapy with radioiodine. Two years later she came back for diffuse bone pain that turned out to be caused by a multiple myeloma, confirmed by bone marrow biopsy. It might be a connection between the severe form of leucopenia that the patient developed and the medullar malignancy.

The clinical course of chronic lymphocytic leukemia (CLL) may be complicated at any time by autoimmune phenomena.The most common ones are hematologic disorders, such as autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP). Pure red cell aplasia (PRCA) and autoimmune agranulocytosis (AG) are, indeed, more rarely seen. However, they are probably underestimated due to the possible misleading presence of cytopenias secondary to leukemic bone marrow involvement or to chemotherapy cytotoxicity. The source of autoantibodies is still uncertain, despite the most convincing data are in favor of the involvement of resting normal B-cells. In general, excluding the specific treatment of underlying CLL, the managementof these complications is not different from that of idiopathic autoimmune cytopenias or of those associated to other causes. Among different therapeutic approaches, monoclonal antibody rituximab, given alone or in combination, has shown to be very effective.

Levamisole-contaminated cocaine has recently been recognized in North America and Europe, and its use is associated with a variety of clinical and autoimmune abnormalities. The clinical characteristic seems to be the presence of a painful purpuric skin rash that predominantly affects the ear lobes and cheeks, often accompanied by systemic manifestations including fever, malaise, arthralgias, myalgias, and laboratory abnormalities, for example leukopenia, neutropenia, positive ANA, ANCA, and phospholipid antibodies. Most of these manifestations can be seen with the use of either drug, especially levamisole. There is no specific therapy, and discontinuation of its use is followed by improvement. Prednisone and immunosuppressive therapy may be needed at times. Further use of the drug is characterized by recurrence of most of the complaints.

The United States Public Health Service Administration is alerting medical professionals that a substantial percentage of cocaine imported into the United States is adulterated with levamisole, a veterinary pharmaceutical that can cause blood cell disorders such as severe neutropenia and agranulocytosis. Levamisole was previously approved in combination with fluorouracil for the treatment of colon cancer; however, the drug was withdrawn from the U.S. market in 2000 because of the frequent occurrence of agranulocytosis. The detection of autoantibodies such as antithrombin (lupus anticoagulant) and an increased risk of agranulocytosis in patients carrying the human leukocyte antigen B27 genotype suggest that toxicity is immune-mediated. In this perspective, we provide an historical account of the levamisole/cocaine story as it first surfaced in 2008, including a succinct review of levamisole pharmacology, pharmacokinetics, and preclinical/clinical evidence for levamisole-induced agranulocytosis. Based on the available information on levamisole metabolism in humans, we propose that reactive metabolite formation is the rate-limiting step in the etiology of agranulocytosis associated with levamisole, in a manner similar to other drugs (e.g., propylthiouracil, methimazole, captopril, etc.) associated with blood dyscrasias. Finally, considering the toxicity associated with levamisole, we propose that the 2,3,5,6-tetrahydroimidazo[2,1-b]thiazole scaffold found in levamisole be categorized as a new structural alert, which is to be avoided in drug design.

A 73-year-old woman with Sjögren's syndrome and autoimmune neutropenia (AIN) associated with large granular lymphocytosis of the polyclonal T cell type, demonstrated autoimmune thrombocytopenia (AIT) at diagnosis of sigmoid colon cancer. Ten months later, both AIN and AIT had exacerbated to agranulocytosis and severe thrombocytopenia below 10×10(9)/L, respectively. There were no dysplastic features of bone marrow hematopoietic cells. Furthermore, an in vitro assay of hematopoietic progenitors showed normal granuloid and erythroid colony formation. Although we serially treated her with prednisolone (oral), filgrastim, intravenous high-dose immunoglobulin infusion, cyclophosphamide (oral), danazol, cyclosporine A (oral), and rituximab, number of neutrophils and platelets elevated only temporarily. During the course of agranulocytosis and severe thrombocytopenia, the patient also developed autoimmune hemolytic anemia (AIHA). She died of pneumonia 5 months after the onset of agranulocytosis. This case is very unique and novel in terms of autoimmune phenomena simultaneously directed to granulocytes, platelets, and red blood cells under the background of Sjögren's syndrome.

Since 2004, the US Food And Drug Administration and the European Medicine Agency are giving warnings about cocaine adulterated with levamisole. Levamisole is primarily used as an anti-helminthic. One of the side-effects of levamisole is a decreased bone marrow function. Herein we describe the first case of agranulocytosis and neutropenic fever due to cocaine adulterated with levamisole reported in Europe.

Propylthiouracil (PTU) is an antithyroid drug which is known to cause drug-induced vasculitis. PTU is implicated in 80-90% of cases of anti-neutrophil cytoplasm circulating antibody (ANCA)-associated vasculitis caused by anti-thyroid drugs which induce ANCA production. Sweet's syndrome is characterized by fever, leucocytosis, neutrophilia and the sudden onset of painful skin lesions. The pathology of the disease is still unclear. Cytokine dysregulation including interleukin-6 and endogenous granulocyte colony-stimulating factor (G-CSF) are thought to play a role in the pathogenesis of Sweet's syndrome. PTU and G-CSF are known to cause Sweet's syndrome and other neutrophilic dermatosis. The presence of ANCA can have a diagnostic value in Sweet's syndrome. Systemic corticosteroids are the first-line therapy for both diseases. Here we report a female patient with Graves' disease who developed ANCA and Sweet's syndrome after using PTU and G-CSF.

Objective: To report a case of a patient with Graves disease presenting with agranulocytosis induced by methimazole, with subsequent thyroid storm and successful therapeutic use of plasmapheresis., Methods: The clinical features and laboratory findings in a patient with agranulocytosis and thyroid storm are presented, and the available literature on utilization of plasmapheresis in the setting of thyrotoxicosis is reviewed., Results: A 40-year-old Vietnamese woman with Graves disease was admitted with methimazole-induced agranulocytosis. Treatment with methimazole was discontinued, and therapy with antibiotics, granulocyte colony-stimulating factor, and ibuprofen was initiated. During hospitalization of the patient, her clinical status deteriorated, with development of pericarditis, thrombocytopenia, and thyroid storm. Treatment with plasmapheresis yielded near-euthyroidism in 3 days. Subsequently, she underwent successful total thyroidectomy., Conclusion: Our case highlights the effectiveness of plasmapheresis when clinical situations prohibit the use of traditional treatment methods for thyrotoxicosis or thyroid storm (or both).

Carbimazole is a drug that is widely used for hyperthyroid disorders, such as Graves' disease. Agranulocytosis is a rare idiosyncratic adverse reaction to the drug which is potentially fatal. This report describes a patient with a history of successfully treated pyoderma gangrenosum, who developed agranulocytosis 3 weeks after commencement of carbimazole for Graves' disease. It may give credence to the theory that implicates antineutrophil cytoplasmic antibodies in the pathogenesis of agranulocytosis induced by antithyroid drugs.

Levamisole is a known contaminant of cocaine and, via this route, has been associated with otherwise unexplained agranulocytosis. Levamisole is currently present in the majority of cocaine samples seized by the US Drug Enforcement Agency. We identified 20 cases of unexplained agranulocytosis in our practice locations of Albuquerque, NM, and Vancouver, Canada. Epidemiologic investigation revealed recent or ongoing cocaine use in 14 cases (70%). Certain morphologic features, including circulating plasmacytoid lymphocytes, increased bone marrow plasma cells, and mild megakaryocytic hyperplasia, were associated with the cocaine-exposed group. Of 5 patients tested, 3 (60%) were HLA-B27+ and showed antineutrophil antibodies, consistent with known associations of levamisole-induced agranulocytosis. One patient, who was positive for cocaine and levamisole by toxicology testing, died of infectious complications. Inadvertent consumption of levamisole via cocaine is a severely under-appreciated risk factor for agranulocytosis, and specific laboratory features are suggestive of this etiology.

The incidence of drug-induced neutropenia has not changed in the western hemisphere over the last 30 years. Yet, the drug panorama has changed considerably. This implies that host factors may play an intriguing role for this idiosyncratic reaction. The knowledge as to mechanisms for the reaction has advanced with emerging understanding of neutropoiesis and immune regulation. Nonetheless, it is still remarkably difficult to pinpoint why and how a drug causes this unexpected, severe adverse event in a patient. Patient characteristics, e.g. genetics, appear to be keys for better understanding, predictions and prevention. Am. J. Hematol. 2009. (c) 2009 Wiley-Liss, Inc.

A 56-year-old female with Crohn's disease was admitted to the hospital with malaise, fever, and a low white blood cell count (0.8 x 10(9)/l) with no granulocytes or myeloid precursor cells in the bone marrow. The leucopenia was initially thought to be the result of an infection and she was treated with antibiotics and granulocyte colony-stimulating factor (G-CSF, filgrastim). However, the bacterial cultures and viral tests were all negative. The patient's condition deteriorated and she became morbidly ill, but recovered after high dose steroid treatment. Six weeks later she relapsed whilst receiving 7.5 mg daily dose of prednisolone. She recovered quickly after being given high dose methylprednisolone in combination with filgrastim. A high maintenance dose of prednisolone was tapered over 5 months. She has not relapsed since and is currently well. Antibodies to the human neutrophil antigen (HNA)-3a were detected, but these antibodies could not easily explain her agranulocytosis as she had a HNA-3a negative phenotype. It seems plausible that her agranulocytosis was immune mediated through autoantibodies directed towards the early myeloid cells.

Clozapine-induced agranulocytosis (CA) is still among the least understood adverse drug reactions in psychopharmacology. In particular, its genetic background is far from being clarified. Within the framework of a case-control study, we performed human leukocyte antigen (HLA) genotyping and haplotype analyses in 42 non-Jewish Caucasian schizophrenic patients (N=42) suffering from CA and 75 non-Jewish Caucasian schizophrenic patients treated with clozapine without developing CA. While controlling for age (P<0.0001) and sex (P=0.835), testing of the alleles from both HLA-loci resulted in borderline results for Cw2 (P=0.085, odds ratio (OR)=0.36, 95% confidence interval (CI): 0.08-1.23), Cw7 (P=0.058, OR=2.0, 95% CI: 0.87-4.63) and DRB5*0201 (P=0.005, adjusted OR=22.15). For haplotype analysis, we obtained significant association results with CA for the two-locus haplotypes HLA-Cw-B (P=0.022) and HLA-DRB5-DRB4 (P=0.050), and for the three-locus haplotype HLA-Cw-B-DRB5 (P=0.030). The complex nature of CA implies that many genes might play a role, but currently, only HLA associations with CA are identified as clinically relevant.

By the action of UVA light, fluphenazine reacted with nucleophiles through a mechanism involving defluorination of its trifluoromethyl group, giving rise to carboxylic acid derivatives that were easily detected by electrospray mass spectrometry. This photoreaction took place with alcohols, sulphydryls, and amines. When irradiation of fluphenazine was carried out in the presence of an amino acid at pH 7.4, the alpha-amino group was covalently bound to the drug. With amino acids possessing a further nucleophilic residue on the side chain, such as lysine, tyrosine, and cysteine--but not serine--both groups reacted, resulting in a fluphenazine-amino acid-fluphenazine diadduct. The same occurred with the physiological peptide glutathione (gamma-glutamylcysteinylglycine). By means of MALDI mass spectrometry, it was shown that fluphenazine also covalently bound to peptides and proteins such as calmodulin. This binding may result in the formation of antibodies, ultimately leading to the destruction of the granulocytes and thus suggesting that photoactivation of this drug may play a role in its clinical side effects, such as agranulocytosis.

Until recently, IgE-activated mast cells have been regarded merely as effector cells of adaptive immune responses, involved in allergic reactions and mucosal immunity to parasites. Herein, we report that murine dermal mast cells, activated by local administration of a cream containing the synthetic TLR7 ligand imiquimod, are essential to initiate an early inflammatory reaction. The mast-cell-derived cytokines TNF-alpha and IL-1beta play an important role in this process. Furthermore, TLR7-activated mast cells are also able to promote the emigration of Langerhans cells, which partly depends on the expression of mast-cell-derived IL-1beta. We have previously shown that TLR7 ligation enhances transcutaneous immunization evoked by topical application of vaccine antigens to the skin, a procedure that directly targets skin-resident antigen-presenting cells. Consequently, we now demonstrate here that the capacity to mount a peptide-specific cytotoxic T-lymphocyte response following transcutaneous immunization using imiquimod as adjuvant is severely impaired in mast-cell-deficient mice. Thus, these findings demonstrate the potent versatility of alternatively activated mast cells at the interface of innate and adaptive immunity.

Basophils represent less than 1% of peripheral blood leukocytes and have often been considered as minor and possibly redundant circulating mast cells. The recent finding that basophils readily generate large quantities of T helper 2 (Th2) cytokines such as IL-4 provided new insights into the possible role of basophils in allergic disorders and immunity to pathogens. However, in-depth studies on basophils, particularly their functions in vivo, have been hampered by the lack of appropriate animal models, such as mutant animals deficient only in basophils. Here, we established a mAb that reacted with mouse basophils and depleted them when administered in vivo. The mAb treatment of mice did not show any significant effect on classical allergic reactions such as passive cutaneous anaphylaxis and contact hypersensitivity. In contrast, it completely abolished the development of IgE-mediated chronic allergic dermatitis that is characterized by massive eosinophil infiltration, even though basophils accounted for only approximately 2% of the infiltrates. The treatment during the progression of the dermatitis resulted in drastic reduction in numbers of infiltrating eosinophils and neutrophils, concomitantly with elimination of basophils from the skin lesions. Thus, basophils play a pivotal role in the development of IgE-mediated chronic allergic inflammation, as an initiator rather than as an effector.

Granulocyte colony-stimulating factor (G-CSF) levels in serum were determined by a highly-sensitive chemiluminescent enzyme immunoassay (limit of detection, 0.5 pg/ml) in 54 patients with Graves' disease including 6 patients complicated with methimazole-induced agranulocytosis. Serum G-CSF levels in patients with Graves' disease were not different from normal subjects and did not correlate with serum FT4 level or circulating neutrophil counts. Before the onset of agranulocytosis, there was no difference in serum G-CSF level between the patients complicated with agranulocytosis and the uncomplicated patients. When circulating neutrophil counts decreased to less than 0.5 x 10(9)/L, serum G-CSF level elevated with the mean of 106.8 +/- 82.2 (SD) pg/ml, but the level did not correlate with the duration of agranulocytosis. Interestingly, maximum serum G-CSF level during the treatment with recombinant human G-CSF (100 microg/day) was related to bone marrow finding at the onset of agranulocytosis and correlated with the duration of agranulocytosis (r = 0.824, p < 0.05). In conclusion, measuring serum G-CSF levels with a highly-sensitive chemiluminescent enzyme immunoassay revealed that 1) thyrotoxicosis does not affect serum G-CSF level, 2) serum G-CSF level during antithyroid drug treatment does not play an important role in development of agranulocytosis, 3) the maximum serum G-CSF level in the course of agranulocytosis is related to the responsiveness of bone marrow to G-CSF and the recovery time from agranulocytosis.

IL-21 is an immune-stimulatory four alpha helix cytokine produced by activated T cells. To study the in vivo antitumor activities of IL-21, TS/A murine mammary adenocarcinoma cells were genetically modified to secrete IL-21 (TS/A-IL-21). These cells developed small tumors that were subsequently rejected by 90% of s.c. injected syngeneic mice. Five days after injection, TS/A-IL-21 tumors showed numerous infiltrating granulocytes, NK cells, and to a lesser extent CD8(+) T cells, along with the expression of TNF-alpha, IFN-gamma, and endothelial adhesion molecules ICAM-1 and VCAM-1. At day 7, CD8(+) and CD4(+) T cells increased together with IFN-gamma, and the CXC chemokines IFN-gamma-inducible protein 10, monokine induced by IFN-gamma, and IFN-inducible T cell alpha-chemoattractant. The TS/A-IL-21 tumor displayed a disrupted vascular network with abortive sprouting and signs of endothelial cell damage. In vivo depletion experiments by specific Abs showed that rejection of TS/A-IL-21 cells required CD8(+) T lymphocytes and granulocytes. When injected in IFN-gamma-deficient mice, TS/A-IL-21 cells formed tumors that regressed in only 29% of animals, indicating a role for IFN-gamma in IL-21-mediated antitumor response, but also the existence of IFN-gamma-independent effects. Most immunocompetent mice rejecting TS/A-IL-21 cells developed protective immunity against TS/A-pc (75%) and against the antigenically related C26 colon carcinoma cells (61%), as indicated by rechallenge experiments. A specific CTL response against the gp70-env protein of an endogenous murine retrovirus coexpressed by TS/A and C26 cells was detected in mice rejecting TS/A-IL-21 cells. These data suggest that IL-21 represents a suitable adjuvant in inducing specific CTL responses.

Background: Haemodialysis (HD) with cuprophan (CU) dialysers leads to a severe transient granulocytopenia. In the present study, we challenge the hypothesis that granulocytes sequester within the pulmonary vasculature simply because this is the first vascular bed encountered. This hypothesis is based upon experiments in which activated plasma or complement fragments were infused into animals, and may not pertain to the more complex HD situation., Methods: We used a rabbit model of HD, and returned the blood into the caval vein (v-HD) or aorta (a-HD). The mesentery was continuously monitored by intravital video microscopy, whereas other tissues were collected at the nadir of granulocytopenia and analysed immunohistochemically., Results: Compared with controls, the number of granulocytes within alveolar walls was almost 2-fold higher following HD, with no difference between venous and arterial blood return. In addition, both v-HD and a-HD induced granulocyte accumulation within part of the larger pulmonary microvessels, though the amount of granulocytes found was 2-fold higher after v-HD. At no time did a-HD induce granulocyte sequestration within the mesenteric microcirculation. Neither did arterial return increase their number in other first-pass tissues like skeletal muscle or renal glomeruli, but it did so in the liver. In the heart, granulocyte content decreased during HD., Conclusions: Pulmonary sequestration of granulocytes during CU HD is not simply a first-pass effect, but is organ specific to a great extent. The accumulation within larger microvessels suggests an important role for adhesion molecules, whereas cellular stiffening may be involved in granulocyte retention within alveolar capillaries.

A patient developed agranulocytosis after Epstein-Barr infection. Bone marrow examination revealed normal myelopoiesis with reduced mature neutrophil polymorphonuclear cells. IgG-specific antineutrophil antibodies (anti-HNA-1a) were found in serum and on polymorphonuclear cells, suggesting that the agranulocytosis after infectious mononucleosis was caused by an autoimmune mechanism.

In two young children with leukaemia, a girl and a boy aged 5 and 4 years, respectively, an invasive infection due to Moraxella catarrhalis was diagnosed at the time of granulocytopenia. They were treated with antibiotics. The first child developed pneumonia and recovered, the other developed severe septic shock and died. M. catarrhalis is a Gram-negative diplococcus, frequently colonising the upper respiratory tract in young children. In childhood this pathogen mainly causes infections such as otitis media and sinusitis, while in adults it primarily causes laryngitis, bronchitis and pneumonia. Immunocompromised patients or patients with chronic cardiopulmonary disease have an increased risk of severe infections.

Objective: To report on an uncommon association of agranulocytosis in primary Sjögren's syndrome (SS)., Methods: The clinical, haematological, and immunological features of seven patients with primary SS associated with a chronic (>6 months) agranulocytosis, and the outcome of the patients, were analysed., Results: Patients were white women with an unexplained agranulocytosis. They all had non-erosive arthritis and three had a thrombocytopenia or Evan's syndrome. In three patients, transient or durable expansion of T lymphocytes was present in the peripheral blood or in the bone marrow, but evolved independently from neutrophil counts. There was no paroxysmal nocturnal haemoglobinuria clone or antibodies to neutrophil surface antigens. In vitro bone marrow culture was normal (four patients) or showed a decrease in colony forming unit-granulocyte monocyte (CFU-GM) and colony forming unit-erythroblast (CFU-E) (one patient). Serum levels of soluble Fas ligand (sFasL) were normal, and granulocyte-colony stimulating factor (G-CSF) concentrations were either normal or raised. One patient was treated with steroids associated with intravenous immunoglobulins and achieved a lasting response. Two other patients were treated with steroids and methotrexate, with poor efficacy. Short courses of subcutaneous G-CSF produced a transient and mild response in all three patients. Complete recovery of the neutrophils occurred temporarily during pregnancy in two patients. After a mean follow up of 34.8 months (range 6-139) all patients were alive and none developed serious infections., Conclusion: A subset of patients with primary SS and non-destructive arthritis may develop a chronic but well tolerated agranulocytosis that is usually poorly responsive to steroids and oral methotrexate.

Pure white cell aplasia (PWCA) is a rare disorder of unknown origin, often associated with thymoma, characterized by selective neutropenia or pure agranulocytosis, and absence of granulocyte precursors in the bone marrow, but with normal erythroblasts and megakaryocytes. We report a case of PWCA associated with thymoma. Unusual findings in this case report included simultaneous presence of autoimmune thyroiditis, type 1 diabetes, anti-striated muscle antibodies, and the presence in the peripheral blood of CD8+ T cells that expressed a homogeneous naive phenotype. Neutrophil count became normal on immunosuppressive therapy after thymectomy.

Recent advances on the pathogenesis of chronic urticaria have defined a group of patients with autoantibodies directed to the IgE or to the alpha chain of the Fc high affinity receptor of IgE, Fc epsilon RI alpha. These antibodies are detected in vivo through the autologous serum test (AST) and in vitro with a variety of techniques. We here describe 37 patients with chronic urticaria, 28 female and 9 male, with a f/m ratio of 3.1. Mean age at onset was 36.5 years (range 16-78). AST was positive in 25 (68%) of 37 patients. Serum induced a wheal significantly larger than plasma (122 +/- 78 mm2 vs 57 +/- 66 mm2, p < 0.05). Median persistence of the chronic urticaria, estimated by Kaplan-Meyer analysis, was 437 days, with no difference between AST(+) and AST(-) patients (437 vs. 369, p = 0.18). Mean IgE concentration was 157 +/- 173 IU/mL, as expected in an unselected population. Basophil count was lower in patients compared with controls (17 +/- 12 cel/microL vs. 43 +/- 27 cel/microL, p < 0.008). Only sera from 2/7 (28.6%) patients AST (+) and very low basophil count consistently induced expression of CD63. This effect was abrogated in non-releasing basophils, confirming the presence of antibodies directed to the Fc epsilon RI alpha-IgE. We conclude that functional antibodies are present in only a minority of patients and that their identification does not predict the outcome.

Invasive pulmonary aspergillosis (IPA) is an acute infection of Aspergillus species to the lungs. It generally occurs in immunocompromised hosts, especially with neutropenia. We report a 30-year-old puerperant, who developed IPA from agranulocytosis. She had been treated for threatened labor with ritodrine and cefepime, one of which induced agranulocytosis. After vaginal delivery of twins, pneumonia emerged in the right lower lobe. She was diagnosed to have IPA according to the halo sign on computed tomography (CT) and positive circulating antibody against Aspergillus, and was treated successfully with oral itraconazole followed by surgical resection. It is important to note that IPA might arise in otherwise immunocompetent hosts when neutropenia is long-standing.

Drug-induced cytopenias are sometimes related to the so-called immuno-allergic mechanism which involves an unusual and unpredictable (i.e.: allergic) immune mediated reaction against the drug, leading to the cell-lysis of either peripheral blood granulocytes, thrombocytes; or erythrocytes. Agranulocytosis is typically induced by amidopyrine, whereas thrombocytopenia and hemolytic anemia are observed with drugs like quinine-quinidine, betalactams antibiotics, sulfonamides, rifampicin etc. In vitro methods for identification of the offending drug are cumbersome and poorly suitable for routine use. Therefore, definite diagnosis in these cases is first based on clinical and hematological grounds. These accidents recover spontaneously. However, potentially severe complications (infection, bleeding) deserve to prevent the risk of recurrence by a lifetime prohibition of the identified or suspected drug.

The role of neutrophils in psoriasis has long been discussed. We report a patient with long-standing psoriasis vulgaris who showed rapid improvement during agranulocytosis caused by ticlopidine. The patient did not develop any new psoriatic lesions for several days, although neutrophils increased daily after the administration of ticlopidine was stopped. The day after the peripheral blood neutrophil count recovered, several psoriatic plaques reappeared. The correlation of psoriatic activity with peripheral blood neutrophil counts suggests that a certain number of neutrophils may be required to initiate and maintain psoriasis.

The use of propylthiouracil (PTU) for the treatment of Graves' disease is associated with few adverse effects such as skin eruptions, liver dysfunction, and agranulocytosis. Furthermore, recent studies described the development of antineutrophil cytoplasmic antibody (ANCA)-related glomerulonephritis and vasculitis in patients treated with PTU. Here we investigated whether PTU therapy per se is associated with the appearance of ANCA in patients with Graves' disease. We analyzed 119 serum samples from 117 patients with Graves' disease treated with either PTU (n = 56), or methimazole (MMI) (n = 21), as well as untreated patients (n = 42). Myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA were tested by enzyme-linked immunosorbent assay (ELISA) kits. MPO-ANCA was negative in all patients treated with MMI therapy and untreated patients. However, MPO-ANCA was detected in 21 (37.5%) of 56 patients treated with PTU therapy. Furthermore, two patients who were negative for MPO-ANCA became positive after PTU therapy. The proportion of patients positive for MPO-ANCA increased with the prolongation of PTU therapy, but did not correlate with age, gender, and positive antithyroperoxidase (TPO) antibody. Among 21 MPO-ANCA positive patients, 12 had no symptoms, but 9 patients complained of myalgia, arthralgia, or common cold like symptoms after the appearance of MPO-ANCA. Three patients developed agranulocytosis or granulocytopenia, but none showed abnormal urinary findings. Our results suggest that PTU per se is associated with the production of MPO-ANCA in patients with Graves' disease.

The atypical antipsychotic agent clozapine is known to be effective in schizophrenic patients refractory to other medications; however, it induces agranulocytosis in approximately 1-2%. In Jews, this complication is associated with the haplotype HLA B38,DR4,DQ3. The aim of the present study was to determine which human leukocyte antigen (HLA) antigens are involved in clozapine-induced agranulocytosis. We performed HLA typing in 88 Jewish Israeli schizophrenic patients and in 127 ethnically matched healthy individuals. Thirty-eight patients responsive to standard antipsychotic medications were treated with haloperidol, and 50 refractory patients received clozapine. A trend was noted for elevated rates of HLA B38 among control individuals and clozapine-treated patients of Ashkenazi origin compared to individuals of non-Ashkenazi origin, but the findings failed to reach statistical significance. No association was found between HLA class I antigens and the response to haloperidol or clozapine. Neutropenia developed in two clozapine-treated patients and agranulocytosis in one. Two of these three patients were of Ashkenazi origin, and both demonstrated the HLA B38 phenotype. Although the findings did not reach a statistical significance because of the small number of patients, they may support an association between clozapine-induced neutropenia/agranulocytosis and Ashkenazi origin and the HLA B38 phenotype. The rate of agranulocytosis in our sample (2%) is similar to the usual cumulative risk of agranulocytosis but in contrast to its high frequency among Jewish American patients. One possible explanation for this difference is the high rate of Ashkenazi patients in the American sample and the preponderance of non-Ashkenazi patients in our population.