Hyperkalemia and maintenance of renin-angiotensin system inhibitor therapy after initiating SGLT-2 or DPP-4 inhibitors.

BACKGROUND: Post-hoc analyses of clinical trials suggest that sodium-glucose cotransporter-2 inhibitors (SGLT-2i) lower the risk of hyperkalemia and facilitate the use of renin-angiotensin system inhibitors (RASi) in people with type 2 diabetes. Whether this is also observed in routine care is unclear. We investigated whether SGLT-2i lowered the risk of hyperkalemia and RASi discontinuation as compared to dipeptidyl peptidase 4 inhibitors (DPP-4i). METHODS: Using the target trial emulation framework, we studied adults with type 2 diabetes (T2D) who started SGLT-2i or DPP-4i in Stockholm, Sweden (2014-2021). The outcomes were incident hyperkalaemia (potassium > 5.0 mmol/L), mild hyperkalemia (potassium > 5-≤5.5 mmol/L) and moderate to severe hyperkalemia (potassium > 5.5 mmol/L). Among RASi users, we studied time to RASi discontinuation through evaluation of pharmacy fills. Cox regression with inverse probability of treatment weighting was used to estimate per-protocol hazard ratios (HRs). RESULTS: 29 849 individuals (15 326 SGLT-2i and 14 523 DPP-4i initiators) were included (mean age 66 years, 37% women). About one third of participants in each arm discontinued treatment within a year. Compared with DPP-4i, SGLT-2i use was associated with a lower rate of hyperkalemia (HR 0.77; 95% CI: 0.64-0.93), including both mild (0.76; 0.62-0.93) and moderate/severe (0.53; 0.40-0.69) hyperkalemia events. Of 19.116 participants that used RASi at baseline, 7% discontinued therapy. Initiation of SGLT-2i vs. DPP-4i was not associated with the rate of RASi discontinuation (0.97; 0.83-1.14). Results were consistent in intention-to-treat analyses and across strata of age, sex, cardiovascular comorbidity, and baseline kidney function. CONCLUSIONS: In patients with diabetes managed in routine clinical care, the use of SGLT-2i was associated with lower rates of hyperkalemia compared with DPP-4i. Possibly because of a relatively high rate of treatment discontinuations, this was not accompanied by higher persistence on RASi therapy.

Quality of laboratory biomarker monitoring during treatment with lithium in patients with bipolar disorder.

BACKGROUND: Clinical guidelines recommend monitoring of creatinine and lithium throughout treatment with lithium. We here assessed the extent to which this occurs in healthcare in Sweden. METHODS: This is an observational study of all adults with bipolar disorder starting lithium therapy in Stockholm, Sweden, during 2007-2018. The main outcome was monitoring of blood lithium and creatinine at therapy initiation and/or once annually. The secondary outcome was monitoring of calcium and thyroid-stimulating hormone (TSH). Patients were followed up until therapy cessation, death, out-migration, or to the end of 2018. RESULTS: We identified 4428 adults with bipolar disorder who started lithium therapy and were followed up for up to 11 years. Their median age was 39 years, and 63% were women. The median duration on lithium therapy was 4.3 (IQR: 1.9-7.45) years, and the majority who discontinued therapy started another mood stabilizer soon after. Overall, 21% started lithium therapy without assessing the serum/plasma concentration of creatinine. The proportion of people who did not have both lithium and creatinine measured increased from 21% in the first year to 33% in the eleventh year. The proportion with annual testing for TSH or calcium was slightly lower. As few as 16% of patients had both lithium and creatinine tested once annually during their complete time on lithium. CONCLUSIONS: In a Swedish community sample, lithium and creatinine monitoring was inconsistent with guideline recommendations that call for measurement of annual biomarker levels.

Pulmonary embolism in a patient with eltrombopag-treated aplastic anaemia and paroxysmal nocturnal haemoglobinuria clone during COVID-19 pneumonia.

Thrombosis in patients with thrombocytopenia has several risk factors, both disease-related and treatment-associated. Recently, COVID-19 infection was recognized as an additional risk factor, further complicating the delicate balance between thrombosis and bleeding in these patients. Here we describe the case of a patient with aplastic anaemia on eltrombopag who developed pulmonary embolism during COVID-19 pneumonia, despite receiving oral anticoagulation with edoxaban. Notably, he was also carrying a large paroxysmal nocturnal haemoglobinuria clone, although without evidence of haemolysis. The presented case recapitulates some of the open questions in thrombotic risk management of cytopenic patients, such as the management of thrombopoietin receptor agonists and the choice of anticoagulation in PNH, while also accounting for the additional thrombotic risk linked to COVID-19.

Evaluation of the introduction of novel potassium binders in routine care; the Stockholm CREAtinine measurements (SCREAM) project.

BACKGROUND: The pharmacological management of hyperkalemia traditionally considered calcium or sodium polystyrene sulfonate and, since recently, the novel binders patiromer and sodium zirconium cyclosilicate. We evaluated their patterns of use, duration of treatment and relative effectiveness/safety in Swedish routine care. METHODS: Observational study of adults initiating therapy with sodium polystyrene sulfonate or a novel binder (sodium zirconium cyclosilicate or patiromer) in Stockholm 2019-2021. We quantified treatment duration by repeated dispensations, compared mean achieved potassium concentration within 60 days, and potential adverse events between treatments. RESULTS: A total of 1879 adults started treatment with sodium polystyrene sulfonate, and 147 with novel binders (n = 41 patiromer and n = 106 sodium zirconium cyclosilicate). Potassium at baseline for all treatments was 5.7 mmol/L. Sodium polystyrene sulfonate patients stayed on treatment a mean of 61 days (14% filled ≥3 consecutive prescriptions) compared to 109 days on treatment (49% filled ≥3 prescriptions) for novel binders. After 15 days of treatment, potassium similarly decreased to 4.6 (SD 0.6) and 4.8 (SD 0.6) mmol/L in the sodium polystyrene sulfonate and novel binder groups, respectively, and was maintained over the 60 days post-treatment. In multivariable regression, the odds ratio for novel binders (vs sodium polystyrene sulfonate) in reaching potassium ≤ 5.0 mmol/L after 15 days was 0.65 (95% CI 0.38-1.10) and after 60 days 0.89 (95% CI 0.45-1.76). Hypocalcemia, hypokalemia, and initiation of anti-diarrheal/constipation medications were the most-commonly detected adverse events. In multivariable analyses, the OR for these events did not differ between groups. CONCLUSION: We observed similar short-term effectiveness and safety for all potassium binders. However, treatment duration was longer for novel binders than for sodium polystyrene sulfonate.

Natural history of chronic idiopathic neutropenia of the adult.

Chronic idiopathic neutropenia (CIN) is a rare benign condition  caused by an immune attack against neutrophils, either primary or in the context of other autoimmune conditions, lymphoproliferative syndromes, and inborn errors of immunity. In this single-center prospective study, 131 adult CIN patients were enrolled (median age 55 years, range: 20-93). At baseline, 56% had anti-neutrophil autoantibodies and 31% had autoimmune comorbidities. Over a median 3-year follow-up, the rate of grade ≥ 2 infections was 42%, with 10% grade ≥ 3, irrespective of neutrophil counts, demographics, and anti-neutrophil antibodies positivity, and G-CSF was used in 6 patients only. No malignant evolution nor deaths were observed. Bone marrow evaluation showed a large granular lymphocyte (LGL) infiltrate in 52%, mostly polyclonal, and hypocellularity in 31% of cases. Immune-histochemistry highlighted deposits of IgG, IgM, and complement fractions C3 and C4d in most cases. Interestingly, 19% of tested patients displayed somatic mutations of myeloid genes with an association with age. In conclusion, adult CIN appears to be a benign condition without life-threatening infections, yet deserving an extensive hematologic evaluation including bone marrow assessment to inform the differential diagnosis.

GLP-1RA vs DPP-4i Use and Rates of Hyperkalemia and RAS Blockade Discontinuation in Type 2 Diabetes.

Importance: Hyperkalemia is a common complication in people with type 2 diabetes (T2D) that may limit the use of guideline-recommended renin-angiotensin system inhibitors (RASis). Emerging evidence suggests that glucagon-like peptide-1 receptor agonists (GLP-1RAs) increase urinary potassium excretion, which may translate into reduced hyperkalemia risk. Objective: To compare rates of hyperkalemia and RASi persistence among new users of GLP-1RAs vs dipeptidyl peptidase-4 inhibitors (DPP-4is). Design, Setting, and Participants: This cohort study included all adults with T2D in the region of Stockholm, Sweden, who initiated GLP-1RA or DPP-4i treatment between January 1, 2008, and December 31, 2021. Analyses were conducted between October 1, 2023, and April 29, 2024. Exposures: GLP-1RAs or DPP-4is. Main Outcomes and Measures: The primary study outcome was time to any hyperkalemia (potassium level >5.0 mEq/L) and moderate to severe (potassium level >5.5 mEq/L) hyperkalemia. Time to discontinuation of RASi use among individuals using RASis at baseline was assessed. Inverse probability of treatment weights served to balance more than 70 identified confounders. Marginal structure models were used to estimate per-protocol hazard ratios (HRs). Results: A total of 33 280 individuals (13 633 using GLP-1RAs and 19 647 using DPP-4is; mean [SD] age, 63.7 [12.6] years; 19 853 [59.7%] male) were included. The median (IQR) time receiving treatment was 3.9 (1.0-10.9) months. Compared with DPP-4i use, GLP-1RA use was associated with a lower rate of any hyperkalemia (HR, 0.61; 95% CI, 0.50-0.76) and moderate to severe (HR, 0.52; 95% CI, 0.28-0.84) hyperkalemia. Of 21 751 participants who were using RASis, 1381 discontinued this therapy. The use of GLP-1RAs vs DPP-4is was associated with a lower rate of RASi discontinuation (HR, 0.89; 95% CI, 0.82-0.97). Results were consistent in intention-to-treat analyses and across strata of age, sex, cardiovascular comorbidity, and baseline kidney function. Conclusions: In this study of patients with T2D managed in routine clinical care, the use of GLP-1RAs was associated with lower rates of hyperkalemia and sustained RASi use compared with DPP-4i use. These findings suggest that GLP-1RA treatment may enable wider use of guideline-recommended medications and contribute to clinical outcomes in this population.

An increase in albuminuria is associated with a higher incidence of malignancies.

Background: A single albuminuria measurement is reported to be an independent predictor of cancer risk. Whether change in albuminuria is also independently associated with cancer is not known. Methods: We included 64 303 subjects of the Stockholm CREAtinine Measurements (SCREAM) project without a history of cancer and with at least two urine albumin-creatinine ratio (ACR) tests up to 2 years apart. Albuminuria changes were quantified by the fold-change in ACR over 2 years, and stratified into the absence of clinically elevated albuminuria (i.e. never), albuminuria that remained constant, and albuminuria that increased or decreased. The primary outcome was overall cancer incidence. Secondary outcomes were site-specific cancer incidences. Results: During a median follow-up of 3.7 (interquartile range 3.6-3.7) years, 5126 subjects developed de novo cancer. After multivariable adjustment including baseline estimated glomerular filtration rate and baseline ACR, subjects with increasing ACR over 2 years had a 19% (hazard ratio 1.19; 95% confidence interval 1.08-1.31) higher risk of overall cancer compared with those who never had clinically elevated ACR. No association with cancer risk was seen in the groups with decreasing or constant ACR. Regarding site-specific cancer risks, subjects with increasing ACR or constant ACR had a higher risk of developing urinary tract and lung cancer. No other associations between 2-year ACR changes and site-specific cancers were found. Conclusions: Increases in albuminuria over a 2-year period are associated with a higher risk of developing overall, urinary tract and lung cancer, independent of baseline kidney function and albuminuria. These data add important weight to the link that exists between albuminuria and cancer incidence.

Androgen use in bone marrow failures and myeloid neoplasms: Mechanisms of action and a systematic review of clinical data.

Despite recent advancements, treatment of cytopenia due to bone marrow failures (BMF) and myeloid neoplasms remains challenging. Androgens promote renewal and maturation of blood cells and may be beneficial in these forms. Here we report a systematic review of androgens use as single agent in hematologic conditions. Forty-six studies, mainly retrospective with various androgen types and doses, were included: 12 on acquired aplastic anemia (AA), 11 on inherited BMF, 17 on myelodysplastic syndromes (MDS), and 7 on myelofibrosis. Responses ranged from 50 to 70% in inherited BMF, 40-50% in acquired AA and MDS, while very limited evidence emerged for myelofibrosis. In acquired AA, response was associated with presence of non-severe disease; in MDS androgens were more effective on thrombocytopenia or mild to moderate anemia, whilst limited benefit was observed for transfusion dependent anemia. Toxicity profile mainly consisted of virilization and liver enzyme elevation, whilst the risk of leukemic evolution remains controversial.

Novel glucose-lowering drugs and the risk of acute kidney injury in routine care; the Stockholm CREAtinine Measurements (SCREAM) project.

INTRODUCTION: Little is known about the comparative effects of sodium glucose cotransporter-2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor agonists (GLP1-RA), or dipeptidyl peptidase-4 inhibitors (DPP-4i) on the risk of acute kidney injury (AKI) in routine care, which may differ from the controlled setting of trials. METHODS: Observational study comparing risks of AKI among new users of SGLT2i, GLP1-RA or DPP-4i in the region of Stockholm, Sweden, during 2008-2018. AKI was defined by ICD-10 codes and creatinine-based KDIGO criteria. We used inverse probability of treatment weighting (IPTW) to adjust for 60 potential confounders, weighted Kaplan-Meier curves and Cox regression to estimate hazard ratios and absolute risks. RESULTS: We included 17,407 participants who newly initiated DPP-4i (N = 10,605), GLP1-RA (N = 4448) or SGLT2i (N = 2354). Mean age was 63 years (39% women) and median (IQR) eGFR was 89 (73-100) ml/min/1.73 m2. During a median follow-up of 2.5 years, 1411 participants experienced AKI. SGLT2i users had the lowest incidence rate of AKI, 18.3 [CI 95% 14.1-23.4] per 1000 person years, followed by GLP1-RA (22.5; 19.9-25.3) and DPP-4i (26.6; 25-28.2). The weighted 3-year absolute risk for AKI was 5.79% [3.63-8.52] in the SGLT2i group, compared with 7.03% [5.69-8.69] and 7.00% [6.43-7.58] in the GLP1-RA and DPP-4i groups, respectively. The adjusted hazard ratio was 0.73 [CI 95% 0.45-1.16] for SGLT2i vs. DPP-4i, and 0.98 [CI 95% 0.82-1.18] for GLP1-RA vs. DPP-4i. CONCLUSION: This study of routine care patients initiating novel glucose-lowering drugs showed similar occurrence of AKI between therapies, and suggests lower risk for SGLT2i.

Real-life monocentric experience of venetoclax-based regimens for acute myeloid leukemia.

Introduction: Combination of venetoclax and hypomethylating agents (HMAs) has become a standard of care in acute myeloid leukemia (AML) aged >75 years or who have comorbidities that preclude intensive induction chemotherapy. Methods: We conducted a monocentric retrospective analysis on adult patients affected by treatment-naïve AML not eligible for standard induction therapy or refractory/relapsed (R/R) AML treated with venetoclax combinations outside clinical trials. Venetoclax was administered at the dose of 400 mg/daily after a short ramp-up and reduced in case of concomitant CYP3A4 inhibitors. Results: Sixty consecutive AML were identified. Twenty-three patients (38%) were affected by treatment-naïve AML and 37 (62%) by R/R AML. Median age was 70 years. Among R/R AML 30% had received a prior allogeneic stem cell transplantation (allo-HSCT). In combination with venetoclax, 50 patients (83%) received azacitidine. Antifungal prophylaxis was performed in 33 patients (55%).Overall response rate was 60%, with 53% of complete remission (CR; 78% for treatment-naïve and 49% for R/R, p 0.017). Median overall survival was 130 days for R/R patients and 269 days for treatment-naïve patients; median event free survival was 145 days for R/R cohort and 199 days for treatment-naïve AML.Measurable residual disease was negative in 26% of evaluable patients in CR/CR with incomplete hematologic recovery after 2 cycles and in 50% after 4 cycles, with no significant association with survival.Eleven patients (18%) received an allo-HSCT after venetoclax combinations. Most common grade 3/4 adverse events were infectious (51% of the patients), or hematological without infections (25% of the patients). Use of CYP3A4 inhibitors was associated with a trend to shorter cytopenias and with a lower rate of infections. Invasive fungal infections were less frequent among patients receiving azole prophylaxis (6% vs 26%; p 0.0659). Discussion: Venetoclax-based regimens are a viable option for AML considered not eligible for standard induction therapy and a valid rescue therapy in the R/R setting.Azole prophylaxis did not significantly affect response and it was associated with a lower rate of invasive fungal infections. Despite a limited number of patients, the association of venetoclax and HMAs proved to be also a feasible bridging therapy to transplantation.

Absolute and Relative Risks of Kidney Outcomes Associated With Lithium vs Valproate Use in Sweden.

Importance: Among patients with bipolar disorder, discordant findings have been published on the nephrotoxic effects of lithium therapy. Objective: To quantify absolute and relative risks of chronic kidney disease (CKD) progression and acute kidney injury (AKI) in people who initiated lithium compared with valproate therapy and to investigate the association between cumulative use and elevated lithium levels and kidney outcomes. Design, Setting, and Participants: This cohort study had a new-user active-comparator design and used inverse probability of treatment weights to minimize confounding. Included patients initiated therapy with lithium or valproate from January 1, 2007, to December 31, 2018, and had a median follow-up of 4.5 years (IQR, 1.9-8.0 years). Data analysis began in September 2021, using routine health care data from the period 2006 to 2019 from the Stockholm Creatinine Measurements project, a recurrent health care use cohort of all adult residents in Stockholm, Sweden. Exposures: New use of lithium vs new use of valproate and high (>1.0 mmol/L) vs low serum lithium levels. Main Outcomes and Measures: Progression of CKD (composite of >30% decrease relative to baseline estimated glomerular filtration rate [eGFR] and kidney failure), AKI (by diagnosis or transient creatinine elevations), new albuminuria, and annual eGFR decrease. Outcomes by attained lithium levels were also compared in lithium users. Results: The study included 10 946 people (median [IQR] age, 45 [32-59] years; 6227 female [56.9%]), of whom 5308 initiated lithium therapy and 5638 valproate therapy. During follow-up, 421 CKD progression events and 770 AKI events were identified. Compared with patients who received valproate, those who received lithium did not have increased risk of CKD (hazard ratio [HR], 1.11 [95% CI, 0.86-1.45]) or AKI (HR, 0.88 [95% CI, 0.70-1.10]). Absolute 10-year CKD risks were low and similar: 8.4% in the lithium group and 8.2% in the valproate group. No difference in the risk of developing albuminuria or the annual rate of eGFR decrease was found between groups. Among more than 35 000 routine lithium tests, only 3% of results were in the toxic range (>1.0 mmol/L). Lithium values greater than 1.0 mmol/L, compared with lithium values of 1.0 mmol/L or less, were associated with increased risk of CKD progression (HR, 2.86; 95% CI, 0.97-8.45) and AKI (HR, 3.51; 95% CI, 1.41-8.76). Conclusions and Relevance: In this cohort study, compared with new use of valproate, new use of lithium was meaningfully associated with adverse kidney outcomes, with low absolute risks that did not differ between therapies. However, elevated serum lithium levels were associated with future kidney risks, particularly AKI, emphasizing the need for close monitoring and lithium dose adjustment.

Albuminuria and the risk of cancer: the Stockholm CREAtinine Measurements (SCREAM) project.

Background: Studies investigating the association of chronic kidney disease and cancer have focused on estimated glomerular filtration (eGFR) rather than on albuminuria. This study aimed to examine whether albuminuria is associated with cancer incidence, and whether this association is independent of eGFR. Methods: We included subjects of the Stockholm Creatinine Measurements (SCREAM) project without a history of cancer-250 768 subjects with at least one urine albumin-creatinine ratio (ACR) test (primary cohort) and 433 850 subjects with at least one dipstick albuminuria test (secondary cohort). Albuminuria was quantified as KDIGO albuminuria stages. The primary outcome was overall cancer incidence. Secondary outcomes were site-specific cancer incidence rates. Multivariable Cox proportional hazards regression models adjusted for confounders including eGFR to calculate hazard ratios and 95% confidence intervals (HRs, 95% CIs). Results: During a median follow-up of 4.3 (interquartile range 2.0-8.2) years, 21 901 subjects of the ACR cohort developed de novo cancer. In multivariable analyses, adjusting among others for eGFR, subjects with an ACR of 30-299 mg/g or ≥300 mg/g had a 23% (HR 1.23; 95% CI 1.19-1.28) and 40% (HR 1.40; 95% CI 1.31-1.50) higher risk of developing cancer, respectively, when compared with subjects with an ACR <30 mg/g. This graded, independent association was also observed for urinary tract, gastrointestinal tract, lung and hematological cancer incidence (all P < .05). Results were similar in the dipstick albuminuria cohort. Conclusions: Albuminuria was associated with the risk of cancer independent of eGFR. This association was primarily driven by a higher risk of urinary tract, gastrointestinal tract, lung and hematological cancers.

Mobility of solid and porous hollow SiO2 nanoparticles in saturated porous media: Impacts of surface and particle structure.

Silica nanoparticles (SiO2 NPs) are of increasing interest in nano-enabled agriculture, particularly as nanocarriers for the targeted delivery of agrochemicals. Their direct application in agricultural soils may lead to the release of SiO2 NPs in the environment. Although some studies have investigated transport of solid SiO2 NPs in porous media, there is a knowledge gap on how different SiO2 NP structures incorporating significant porosities can affect the mobility of such particles under different conditions. Herein, we investigated the effect of pH and ionic strength (IS) on the transport of two distinct structures of SiO2 NPs, namely solid SiO2 NPs (SSNs) and porous hollow SiO2 NPs (PHSNs), of comparable sizes (~200 nm). Decreasing pH and increasing ionic strength reduced the mobility of PHSNs in sand-packed columns more significantly than for SSNs. The deposition of PHSNs was approximately 3 times greater than that of SSNs at pH 4.5 and IS 100 mM. The results are non-intuitive given that PHSNs have a lower density and the same chemical composition of SSNs but can be explained by the greater surface roughness and ten-fold greater specific surface area of PHSNs, and their impacts on van der Waals and electrostatic interaction energies.

Use of nephrotoxic medications in adults with chronic kidney disease in Swedish and US routine care.

Background: To characterize the use of nephrotoxic medications in patients with chronic kidney disease (CKD) Stages G3-5 in routine care. Methods: We studied cohorts of adults with confirmed CKD G3-5 undergoing routine care from 1 January 2016 through 31 December 2018 in two health systems [Stockholm CREAtinine Measurements (SCREAM), Stockholm, Sweden (N = 57 880) and Geisinger, PA, USA (N = 16 255)]. We evaluated the proportion of patients receiving nephrotoxic medications within 1 year overall and by baseline kidney function, ranked main contributors and examined the association between receipt of nephrotoxic medication and age, sex, CKD G-stages comorbidities and provider awareness of the patient's CKD using multivariable logistic regression. Results: During a 1-year period, 20% (SCREAM) and 17% (Geisinger) of patients with CKD received at least one nephrotoxic medication. Among the top nephrotoxic medications identified in both cohorts were non-steroidal anti-inflammatory drugs (given to 11% and 9% of patients in SCREAM and Geisinger, respectively), antivirals (2.5% and 2.0%) and immunosuppressants (2.7% and 1.5%). Bisphosphonate use was common in SCREAM (3.3%) and fenofibrates in Geisinger (3.6%). Patients <65 years of age, women and those with CKD G3 were at higher risk of receiving nephrotoxic medications in both cohorts. Notably, provider awareness of a patient's CKD was associated with lower odds of nephrotoxic medication use {odds ratios [OR] 0.85[95% confidence interval (CI) 0.80-0.90] in SCREAM and OR 0.80 [95% CI 0.72-0.89] in Geisinger}. Conclusions: One in five patients with CKD received nephrotoxic medications in two distinct health systems. Strategies to increase physician's awareness of patients' CKD and knowledge of drug nephrotoxicity may reduce prescribing nephrotoxic medications and prevent iatrogenic kidney injury.

Follicular lymphoma subgroups with and without t(14;18) differ in their N-glycosylation pattern and IGHV usage.

We previously reported that t(14;18)-negative follicular lymphomas (FL) show a clear reduction of newly acquired N-glycosylation sites (NANGS) in immunoglobulin genes. We therefore aimed to investigate in-depth the occurrence of NANGS in a larger cohort of t(14;18)-positive and t(14;18)-negative FL, including early (I/II) and advanced (III/IV) stage treatment-naive and relapsed tumors. The clonotype was determined by using a next-generation sequencing approach in a series of 68 FL with fresh frozen material [36 t(14;18) positive and 32 t(14;18) negative]. The frequency of NANGS differed considerably between t(14;18)-positive and t(14;18)-negative FL stage III/IV, but no difference was observed among t(14;18)-positive and t(14;18)-negative FL stage I/II. The introduction of NANGS in all t(14;18)-negative clinical subgroups occurred significantly more often in the FR3 region. Moreover, t(14;18)-negative treatment-naive FL, specifically those with NANGS, showed a strong bias for IGHV4-34 usage compared with t(14;18)-positive treatment-naive cases with NANGS; IGHV4-34 usage was never recorded in relapsed FL. In conclusion, subgroups of t(14;18)-negative FL might use different mechanisms of B-cell receptor stimulation compared with the lectin-mediated binding described in t(14;18)-positive FL, including responsiveness to autoantigens as indicated by biased IGHV4-34 usage and strong NANGS enrichment in FR3.