'Double whammy': An Unusual Co-occurrence of Idiosyncratic phenytoin-induced agranulocytosis and acute liver failure in a child.

Idiosyncratic adverse events to phenytoin therapy, such as agranulocytosis and acute liver failure, though rare, may be life-threatening. Simultaneous occurrence of both adverse events is exceedingly rare; only two cases have been reported in the literature to date. We describe such a case in a 15-year-old girl. Prompt haematological and hepatic recovery occurred after discontinuation of the drug. Given the widespread use of phenytoin in seizure disorders, clinicians prescribing this drug should be aware of its potential complications. Early recognition can considerably improve outcomes.

Pure white cell aplasia before and after thymectomy in the rare conundrum of thymoma: A case report and review of the literature.

RATIONALE: Pure white cell aplasia (PWCA) is a rare paraneoplastic syndrome that occurs in patients with thymomas. Currently, the pathogenesis and treatment of this disease remain in the exploratory stage. PATIENT CONCERNS: We report a 68-year-old woman with thymoma experienced PWCA involvement as her first presentation. The patient had high fever and agranulocytosis at the onset of the disease. The white blood cell count in the complete blood count was 1.9 × 109/L with a neutrophil of 0.1 × 109/L. The bone marrow aspirates showed decreased granulocyte proliferation. Computed tomography showed a large mass in the anterior mediastinum. DIAGNOSES: The final diagnosis of our patient was PWCA and thymoma. INTERVENTIONS: She underwent a thymectomy and cyclosporine A administration during first remission. OUTCOMES: Long-term remission was achieved following the readministration of cyclosporine A after the disease recurrence. LESSONS: PWCA or agranulocytosis with thymoma has been confirmed to be an extremely rare disease. Thymomas with PWCA correlate with autoimmunity. From this case study and the literature review, we concluded that the pathogenesis of thymomas in PWCA is mainly related to the activation of autoreactive T cells. Thymectomy and the immunosuppressive drug, cyclosporine A, were chosen for treatment. The patient's granulocyte levels were unable to recover after surgery because of the inability to promptly clear activated T cells. After surgery, cyclosporine A continued to take for a long time. Thymectomy combined with prolonged cyclosporine A administration may be an effective method for treating this rare disease.

Novel Association of KLRC4-KLRK1 Gene Polymorphisms with Susceptibility and Progression of Antithyroid Drug-Induced Agranulocytosis.

OBJECTIVE: Antithyroid drug (ATD)-induced agranulocytosis (TIA) is the most serious adverse effect during ATD treatment of Graves' disease (GD). Previously, the MICA gene was reported to be associated with TIA. MICA protein is an important ligand for the NKG2D protein, which is encoded by the KLRK1 gene and KLRC4-KLRK1 read-through transcription. This study further investigated the association between KLRC4-KLRK1 gene polymorphisms and susceptibility to TIA. METHODS: Twenty-eight candidate single nucleotide polymorphisms (SNPs) on KLRC4-KLRK1 read-through transcription were evaluated by the iPLEX MassARRAY system in 209 GD control patients and 38 TIA cases. RESULTS: A significant association of rs2734565 polymorphism with TIA was found (p=0.02, OR=1.80, 95% CI=1.09-2.96). The haplotype C-A-A-C-G, including rs2734565-C, was associated with a significantly higher risk of TIA (p=4.79E-09, OR=8.361, 95% CI=3.737-18.707). In addition, the interval time from hyperthyroidism to agranulocytosis onset was shorter in patients carrying the rs2734565-C allele than in non-carrying groups (45.00 (14.00-6570.00) d vs. 1080.00 (30.00-3600.00) d, p=0.046), and the interval from ATD treatment to agranulocytosis onset was also shorter in patients carrying rs2734565-C allele (29.00 (13.00-75.00) d vs. 57.50 (21.00-240.00) d, p=0.023). CONCLUSIONS: The findings suggest that the KLRC4-KLRK1 gene polymorphism is associated with susceptibility and progression of ATD-induced agranulocytosis. Patients carrying the rs2734565-C allele had a higher susceptibility and faster onset time of TIA.

Clozapine-Associated Agranulocytosis: A Systematic Review. Is It Really So Frighteningly Common?

BACKGROUND: Clozapine is a very effective therapeutic option for schizophrenic disorders that have been refractory to most other therapies. This extremely positive aspect clashes easily with an adverse effect of the drug that is deemed to be a very dangerous one: agranulocytosis. We asked whether the mandatory strict hematological follow-up prescribed in the black box warning of clozapine's label is proportioned to the actual incidence of agranulocytosis, considering that is the main reason that such a drug is often used only late in the treatment course. METHODS: We carried out a systematic review of reports examining clozapine administration and agranulocytosis incidence. We specifically selected those where mild and moderate neutropenia was not used as a trigger to stop administration of clozapine, to better estimate the sheer incidence of agranulocytosis when clozapine was continued even with mild hematological effect, where detected. We used PubMed, MEDLINE, EMBASE, Cochrane, and ScienceDirect databases to identify clinical studies conducted between January 1975 and April 2023. RESULTS: We included 14 studies, mostly retrospective ones, that examined the incidence of hematological adverse effects in patients using clozapine. A total of 2354 subjects were included. The mean age of the subjects was 33.5 years. The mean duration of observation of subjects who took clozapine was 800 days, with a mean daily dose of 319.5 mg per day. Of the 2354 subjects examined, we found that 11 of them experienced agranulocytosis (0.47%). CONCLUSIONS: These results suggest the evidence of a lower incidence of agranulocytosis than previously estimated and are in line with more recent meta-analyses. We may therefore think that clinical practice may demand a revision of the approach that both psychiatrists and supervising organizations often take when talking about clozapine.

Clinical characteristics and risk factors of acute lymphoblastic leukemia in children with severe infection during maintenance treatment.

BACKGROUND: Infection is the most common adverse event of acute lymphoblastic leukemia (ALL) treatment and is also one of the main causes of death. METHODS: To investigate the clinical characteristics and risk factors of severe infections during the maintenance phase of ALL treatment, we conducted a retrospective study. RESULTS: A total of 181 children were eligible and 46 patients (25.4%) suffered from 51 events of severe infection, most of which occurred in the first half year of the maintenance phase (52.9%). The most common infection was pulmonary infection (86.3%) followed by bloodstream infection (19.6%). The main symptoms of ALL patients with pulmonary infection were fever, cough, and shortness of breath. The main manifestations of computer tomography (CT) were ground glass shadow (56.8%), consolidation shadow (27.3%), and streak shadow (25%). Multivariate binary logistic regression analysis showed that agranulocytosis, agranulocytosis ≥7 days, anemia, and low globulin level were independent risk factors for severe infection during the maintenance phase (all p < 0.05). CONCLUSIONS: Taken together, blood routine examinations and protein levels should be monitored regularly for ALL patients in the maintenance phase, especially in the first 6 months. For ALL patients with risk factors, preventive anti-infective or supportive therapies can be given as appropriate to reduce the occurrence of severe infections.

As-Required Filgrastim for Late-Onset Neutropenia Complicating Long-Term Clozapine Treatment: a Case Report.

Clozapine is considered the most effective antipsychotic for schizophrenia, but it can cause neutropenia and even agranulocytosis. We describe the first case in Hong Kong involving the use of filgrastim, a recombinant form of human granulocyte colony-stimulating factor, to enable clozapine continuation therapy for a severely ill patient with treatment-resistant schizoaffective disorder who developed recurrent neutropenia after almost 20 years of continuous clozapine therapy. Therefore, clinical vigilance is important, regardless of clozapine treatment duration. Filgrastim can facilitate long-term clozapine therapy in patients with clozapine-induced neutropenia.

Impact of rhG-CSF on Clinical Efficacy and Immune Cell Subsets after Initial Induction Chemotherapy in AML.

BACKGROUND: The impact of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in acute myeloid leukemia (AML) is still controversial. The purpose of this study is to explore the impact of rhG-CSF administration on clinical efficacy and immune cell subsets after initial induction chemotherapy in AML. METHODS: The clinical efficacy and immune cell subsets were compared in the newly diagnosed patients with AML according to whether rhG-CSF was used after initial induction chemotherapy. Next, rhG-CSF stimulation experi-ments on leukemia cell lines and primary leukemia blasts were performed in vitro. RESULTS: There was no statistical difference between control group and rhG-CSF therapy group in complete remission rate and relapse free survival. The duration of agranulocytosis was significantly shortened in rhG-CSF therapy group compared with control group. The percentage of circulating monocytic myeloid-derived suppressor cells (M-MDSCs) and regulatory T cells (Tregs) were significantly increased after the administration of rhG-CSF. Furthermore, it was found that rhG-CSF did not promote the proliferation of leukemia cell lines and primary leukemia blasts, but increased the proportion of M-MDSCs and Tregs in vitro. CONCLUSIONS: Administration of rhG-CSF after initial induction therapy of AML does not affect the clinical remission and relapse rate, but reduces the duration of agranulocytosis and increases the proportion of M-MDSCs and Tregs.

Real-world evidence for beneficial effects of dipyrone in 4,278 patients with pulmonary hypertension - Analysis of the risk of ventilation, hospitalization, and agranulocytosis.

INTRODUCTION: Dipyrone has been used as an analgesic for a century, but recently was proposed as a novel therapeutic strategy for the prevention and therapy of pulmonary hypertension (PH). The aim of this study was to analyze whether the risk for ventilation procedures and hospitalization was lower among patients with PH who used dipyrone compared to subjects who did not use dipyrone. MATERIALS AND METHODS: Initially, patients with PH were retrieved from the TriNetX database, whereby subjects who used dipyrone were assigned to cohort I, and cohort II was formed by those individuals who did not use dipyrone. Both cohorts were matched for several variables. The outcomes were requirement for ventilation procedures and hospital admission, whereby the time window to record events was 5 years after diagnosis of PH. Subsequently, risk analysis was carried out, and risk ratio (RR) and odds ratio (OR) were calculated. In addition, the risk of agranulocytosis was determined for both cohorts. RESULTS: Out of 741,875 individuals diagnosed with PH 4,282 and 737,593 patients were assigned to the cohorts I and II. After matching, each cohort accounted for 4,278 individuals. Among the cohorts I and II 10 and 187 individuals required ventilation procedures. The according risks of 0.2% vs. 4.4% were significantly different (p < 0.0001; Log-Rank test). RR and OR were 0.053 and 0.051. Within the cohorts I and II 10 and 1,195 subjects required hospital admission. The risks of hospitalization of 0,4% vs. 27.9% differed significantly (p < 0.0001). RR and OR were 0.016 and 0.012. Among the cohorts I and II 47 and 66 individuals were diagnosed with agranulocytosis, whereby no significance was found (p > 0.05). CONCLUSIONS: The risk for ventilation measures and hospitalization among patients with PH was found to be significantly lower when dipyrone was used. Even though the underlying mechanisms remain unknown to date, they are supposedly mediated by an active metabolite of dipyrone. The obtained results appear to be promising for patients suffering from PH. Hence, the present study may encourage further research.

Unmasking of Metamizole-induced Liver Injury by Simult aneous Development of Characteristic Agranulocytosis.

BACKGROUND: Metamizole is one of the most used analgesic, antipyretic, and spasmolytic agents in many countries worldwide. While metamizole-induced agranulocytosis is an, albeit seldom, well-known adverse event, metamizole-associated drug-induced liver injury has been reported rarely in the literature and hence often remains unconsidered. Here, we present a unique case where metamizole-induced hepatotoxicity got unmasked by the simultaneous development of characteristic agranulocytosis. CASE REPORT: A 22-year-old woman without known conditions presented with a new onset of fever, jaundice, and maculopapular rash and explicitly denied intake of any new substances. Laboratory tests showed liver injury, granulopenia, and positive anti-nuclear and anti-mitochondrial (AMA-M2) antibodies. Liver biopsy revealed a histological pattern characteristic of drug-induced liver injury and bone marrow biopsy, the classical picture of metamizole-induced agranulocytosis. Indeed the in-depth interview of the patient unveiled metamizole consumption over the last two months. Therefore, we could diagnose metamizole-induced hepato- and myelotoxicity. Accordingly, steroid therapy led to normalization of liver parameters and stimulation with granulocyte colony- stimulating factor to leukocyte recovery. CONCLUSION: This case report is intended to increase the awareness of metamizole-associated druginduced liver injury which should always be kept in mind due to its occasionally life-threatening course. Diagnosis can be difficult particularly if anamnesis and written records are without hints for prior metamizole intake.

Efficacy and Safety of the PD-1 Inhibitor Combined with Albumin-Bound Paclitaxel and Nedaplatin in Preoperative Neoadjuvant Therapy of Unresectable Stage III Lung Squamous Cell Carcinoma.

Aim: To investigate the efficacy and safety of preoperative neoadjuvant therapy (PD-1 inhibitor plus nab-PTX and nedaplatin) for resectable stage III lung squamous cell carcinoma (SCC) patients. Methods: Patients with locally advanced lung SCC (stage IIIA, IIIB) who received PD-1 inhibitor combined with nab-PTX and NED between February 2019 and June 2021 in Weihai Municipal Hospital were included and underwent surgical treatment 4 weeks after 2-4 cycles neoadjuvant therapy. The rate of resection R0, the effective rate, the complete pathological remission rate (pCR) and the rate of major pathological remission (MPR) were observed. Results: A total of 14 initially unresectable male patients with lung SCC were included and received neoadjuvant treatment after evaluation. Nine out of 14 patients (64.3%) experienced treatment-related adverse events (TRAE), among which 8 (57.1%) experienced grade (G) I-II TRAEs including nausea, vomiting, fatigue, constipation, elevated ALT and AST, hyperthyroidism, hypothyroidism, rash, granulocytopenia, and thrombocytopenia, and 1 (7.1%) experienced grade III-V TRAEs (G), including granulocytopenia and atelectasis. Thirteen patients (92.86%) achieved RECIST-assessed partial remission (PR), while 1 patient (7.14%) achieved stable disease (SD) on imaging assessment after neoadjuvant treatment and continued to be progression-free for 26 months. Of the 11 patients who underwent resection, all were alive and recurrence/progression-free. MPR and pCR were observed in 2 (18.18%) and 9 (81.82%), respectively. IHC results exhibited that all NSCLC patients exhibited positive PD-L1 expression (9/14, TPS ≥50% or greater; 5/14, 1% < TPS < 50%). Two were negative for ALK, EGFR, and ros-1, and the rest were not examined for driver oncogene mutation. Conclusion: The neoadjuvant therapy of the PD-1 inhibitor combined with nab-PTX and NED demonstrated remarkable therapeutic efficacy and good safety on stage III lung SCC without increasing the risk of TRAE, mortality and surgery-related complications, or impede surgery feasibility.

A Medication Hiccup: Chlorpromazine-Induced Agranulocytosis in a 72-Year-Old Male.

INTRODUCTION: Agranulocytosis, a severe decrease or absence of neutrophils, is a side effect of several medications, including chlorpromazine. If not promptly recognized, it can lead to overwhelming infection, sepsis, and death. CASE PRESENTATION: A 72-year-old man with adenocarcinoma of the lung status-post recent lobectomy was admitted for postsurgical pain and electrolyte derangement. During his admission, he had intractable hiccups and was started on chlorpromazine 25 mg by mouth 3 times a day. Within a week, he developed pneumonia, type 1 respiratory failure, and a progressive neutropenia. Chlorpromazine-induced agranulocytosis was suspected and chlorpromazine was discontinued; however, the patient expired, with postmortem findings of aspergillus bronchopneumonia as cause of death. DISCUSSION: Chlorpromazine is a well-studied cause of agranulocytosis. This case is novel in its rapid time course of less than 1 week; most cases report the resultant agranulocytosis on the order of weeks rather than days. CONCLUSION: This case highlights an important need to recognize this medication side effect early so the offending agent may be stopped and the patient properly supported, so as to avoid the severe risk of neutropenic infection, sepsis, and death.

Long-term treatment with clozapine and other antipsychotic drugs and the risk of haematological malignancies in people with schizophrenia: a nationwide case-control and cohort study in Finland.

BACKGROUND: Clozapine is the most efficacious treatment for schizophrenia and is associated with lower overall mortality than are other antipsychotic drugs, despite the risk of agranulocytosis. Preliminary reports over the past 10 years suggest a possible risk of haematological malignancies, but the issue has remained unsettled. We aimed to study the risk of haematological malignancies associated with use of clozapine and other antipsychotics. METHODS: We did a nationwide case-control (and cohort) study of people with schizophrenia, using prospectively gathered data from Finnish national registers. A nested case-control study was constructed by individually matching cases of lymphoid and haematopoietic tissue malignancy with up to ten controls without cancer by age, sex, and time since first schizophrenia diagnosis. For the case-control study, we restricted inclusion criteria to malignancies diagnosed on a histological basis, and excluded individuals outside of the age range 18-85 years, and any patients that had a previous malignancy. Analyses were done using conditional logistic regression adjusting for comorbid conditions. FINDINGS: For the case-control study 516 patients with a first-time diagnosis of lymphoid and haematopoietic tissue malignancy during years 2000-17 and diagnosed after their first diagnosis of schizophrenia were identified. 102 patients were excluded due to diagnosis that was without a histological basis, five patients were excluded because of their age, and 34 were excluded for a previous malignancy, resulting in 375 patients being matched to controls. We selected up to ten controls without cancer (3734 in total) for each case from the base cohort of people with schizophrenia. For the cohort study, data for 55 949 people were included for analysis. Cumulative incidence of haematological malignancies during the mean follow-up of 12·3 years (SD 6·5) was 102 (0·7%) cases among 13 712 patients who had used clozapine (corresponding to event rate of 61 cases per 100 000 person-years), and during mean follow-up of 12·9 years (SD 7·2) was 235 (0·5%) malignancies among 44 171 patients having used other antipsychotic medication than clozapine (corresponding to 41 cases per 100 000 person-years). Of the 375 individuals with haematological malignancies (305 lymphomas, 42 leukaemia, 22 myelomas, 6 unspecified) observed from 2000-17, 208 (55%) were males and 167 (45%) were female. Ethnicity data were not available. Compared with non-use of clozapine (most had used other antipsychotics and a few had used no antipsychotics), clozapine use was associated with increased odds of haematological malignancies in a dose-response manner (adjusted odds ratio 3·35, [95% CI 2·22-5·05] for ≥5000 defined daily dose cumulative exposure, p<0·0001). Exposure to other antipsychotic drugs was not associated with increased odds. A complementary analysis showed that the clozapine-related risk increase was specific for haematological malignancies, because no such finding was observed for other malignancies. Over 17 years of follow-up of the base cohort, 37 deaths occurred due to haematological malignancy among patients exposed to clozapine (26 with ongoing use at time of haematological malignancy diagnosis, and 11 in patients who did not use clozapine at the exact time of their cancer diagnosis), whereas only three deaths occurred due to agranulocytosis. INTERPRETATION: Unlike other antipsychotics, long-term clozapine use is associated with increased odds of haematological malignancies. Long-term clozapine use has a higher effect on mortality due to lymphoma and leukaemia than due to agranulocytosis. However, acknowledging that the absolute risk is small compared with the previously observed absolute risk reduction in all-cause mortality is important. Our results suggest that patients and caregivers should be informed about warning signs of haematological malignancies, and mental health clinicians should be vigilant for signs and symptoms of haematological malignancy in patients treated with clozapine. FUNDING: The Finnish Ministry of Social Affairs and Health and Academy of Finland.

Clozapine and COVID-19 Vaccination: Effects on blood levels and leukocytes. An observational cohort study.

OBJECTIVE: To investigate the safety of COVID-19 vaccination in patients on clozapine as regards plasma clozapine concentration and haematological parameters. METHODS: We conducted a multicentre observational cohort study from 22 February 2021 to 2 September 2021. Primary outcomes were clinically relevant increase in clozapine blood levels (>100 µg/L increase compared to baseline) and clozapine alert levels (>1000 µg/L). Secondary outcomes were granulocytopenia, leukocytopenia and lymphocytopenia. Outcomes were measured approximately 5 days after the first and (where applicable) second dose of COVID-19 vaccine. RESULTS: This study included 139 patients. Compared to baseline, clozapine blood levels increased significantly (ES = 0.28, p = 0.003) after the second vaccination. Clinically relevant increases in clozapine blood levels occurred in 20/92 patients (22%) and in 16/56 patients (29%) during the first and second phases, respectively. Clozapine alert levels developed in one patient (1%) following the first dose and in three patients (5%) after the second dose. In both phases, changes in white blood cells (WBC) were limited to mild granulocytopenia (3% and 5%), moderate granulocytopenia (1% and 0%) and leukocytopenia (2% and 3%) without cause for extra monitoring according to the guideline. CONCLUSION: In general, as regards WBC counts COVID-19 vaccination seems to be safe in patients with SMI. Changes in WBC had no clinical implications. Psychoeducation on the symptoms of clozapine intoxication is recommended, especially in patients with clozapine blood levels approaching the upper limit of the therapeutic range. Increase in the C-reactive protein (CRP) level can signal inflammation rapidly and help to prevent clozapine intoxication following vaccination.

Absolute Agranulocytosis After 9 Weeks of Clozapine 25 mg Daily.

BACKGROUND: Clozapine has been shown to be an effective and well-tolerated treatment for Parkinson disease (PD) psychosis as well as for refractory tremor in PD. Doses used are generally less than one tenth those used in treating schizophrenia. While the risk of leukopenia and agranulocytosis are reported to be independent of dose, that belief is based on the use of doses used in refractory schizophrenia. There are no published data on the risk of agranulocytosis in patients taking extremely low doses of clozapine. CASE REPORT: This 87-year-old man with diabetes and PD experienced a granulocyte count drop from normal, 3900, at dose initiation, to 0, at the ninth week of treatment taking clozapine 12.5 mg twice daily for refractory tremor. He recovered without developing an infection. CONCLUSIONS: This is the first known reported case of agranulocytosis due to clozapine used at an extremely low dose. This report underscores the importance of blood monitoring, even at extremely low doses, although the exact risk remains unknown.

A puerperal patient with agranulocytosis during tazobactam / piperacillin administration†:†A case report.

Tazobactam / piperacillin (TAZ / PIPC) is an injectable combination drug consisting of a broad-spectrum penicillin and a ß-lactamase inhibitor. This antimicrobial has a wide spectrum of efficacy against both Gram-positive bacteria and anaerobes. Adverse events usually present as diarrhea or liver dysfunction ; agranulocytosis has not been reported in Japanese patients with puerperal disorders. However, we report a 32-year-old Japanese woman who received TAZ / PIPC to treat an intraperitoneal infection that developed after complications related to transvaginal delivery. Within 14 days of beginning TAZ / PIPC therapy, the patient developed agranulocytosis, indicated by a white blood cell count of 1900 cells / µL and a neutrophil count of 475 cells / µL. We discontinued TAZ / PIPC at this point and changed the antimicrobial to meropenem. Seven days later, her white blood cell count increased to 3700 cells / µL (neutrophil count : 1684 cells / µL), and the intraperitoneal infection resolved. Patients receiving TAZ / PIPC should be monitored periodically for agranulocytosis as well as for diarrhea and liver dysfunction. J. Med. Invest. 68 : 368-371, August, 2021.

Naringin treatment improved main clozapine-induced adverse effects in rats; emphasis on weight gain, metabolic abnormalities, and agranulocytosis.

Schizophrenia is one of the major neuropsychiatric disorders affecting people worldwide. Unfortunately, currently available antipsychotic medications possess several side effects. Among them, clozapine is one of the atypical antipsychotics prescribed in schizophrenia wing to its blocking effect on dopamine (D2) and serotonin (5-HT1c ) receptors. However, it has been recently reserved for resistant schizophrenia due to its several side effects. The current research aimed at investigating potential naringin add-on benefit to cease the main side effects of clozapine in ketamine-induced psychosis in rats. In this study, schizophrenia was induced in rats via ketamine administration that could promote neuropathological patterns of schizophrenia. Afterwards, clozapine and naringin were administered to rats in order to improve such effects induced by ketamine. Clozapine administration promoted weight gain, hyperglycemia, dyslipidemia, and agranulocytosis. However, naringin was able to reduce such adverse effects when added to clozapine treatment. Naringin increased total leukocyte count preventing agranulocytosis either when administered alone or in combination with clozapine. In addition, via its metabolic activities, naringin treatment lowered serum total cholesterol and triglycerides levels. Moreover, naringin prevented weight gain when administered. Finally, naringin reduced serum glucose level preventing hyperglycemia associated with clozapine treatment. Collectively, these findings may suggest that naringin possesses a potential add-on benefit to clozapine in treatment of schizophrenia.

Case Report: High Doses of Intravenous Immunoglobulins as a Successful Treatment for Late Onset Immune Agranulocytosis After Rituximab Plus Bendamustine.

Late onset neutropenia (LON) related to rituximab or rituximab plus chemotherapy is defined as an unexplained absolute neutrophil count of ≤1.5 × 109/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.