Low Fcgamma receptor III and high granulocyte colony-stimulating factor serum levels correlate with the risk of infection in neutropenia due to Felty's syndrome or systemic lupus erythematosus

The prevalence of neutropenia and association with infections in patients with systemic lupus erythematosus: a Swedish single-center study conducted over 14 years

Hematologic abnormalities are common manifestations of SLE, although neutropenia is observed less frequently and is not included in the classification criteria. Nonetheless, neutropenia is a risk factor for infections, especially those caused by bacteria or fungi. We aimed to evaluate the impact of neutropenia in SLE through a systematic investigation of all infections in a large cohort of well-characterized patients, focusing on neutropenia, lymphopenia, and hypocomplementemia. Longitudinal clinical and laboratory parameters obtained at visits to the Rheumatology Unit, Linköping University Hospital, and linked data on all forms of healthcare utilization for all the subjects included in our regional SLE register during 2008-2022 were assessed. Data regarding confirmed infections were retrieved from the medical records. Overall, 333 patients were included and monitored during 3,088 visits to a rheumatologist during the study period. In total, 918 infections were identified, and 94 occasions of neutropenia (ANC < 1.5 × 109/L) were detected in 40 subjects (12%). Thirty neutropenic episodes in 15 patients occurred in association with infections, of which 13 (43%) required in-hospital care, 4 (13%) needed intensive care, and 1 (3%) resulted in death. Bayesian analysis showed that patients with ≥ 1 occasion of neutropenia were more likely to experience one or more infections (OR = 2.05; probability of association [POA] = 96%). Both invasiveness (OR = 7.08; POA = 98%) and severity (OR = 2.85; POA = 96%) of the infections were significantly associated with the present neutropenia. Infections are common among Swedish SLE patients, 12% of whom show neutropenia over time. Importantly, neutropenia is linked to both the invasiveness and severity of infections. Awareness of the risks of severe infections in neutropenic patients is crucial to tailor therapies to prevent severe illness and death.

Activation of stem cell up-regulation/mobilization: a cardiovascular risk in both mice and humans with implications for liver disease, psoriasis and SLE

Experimentally induced injury triggers up-regulation and mobilization of stem cells in Apoe -/- mice that causes accelerated atherosclerosis. Abca1 -/- Abcg1-/- mice have chronic activation of stem cell up-regulation/mobilization and accelerated atherosclerosis. In addition, the Abca1 -/- Abcg1-/- mice have elevation of serum cytokines G-CSF, IL-17 and IL-23, each necessary for stem cell mobilization. IL-17 and IL-23 are elevated in two human illnesses that have cardiovascular (CV) risk independent of traditional risk factors—SLE and psoriasis. Serum G-CSF, which can be elevated in liver disease, predicts major adverse cardiovascular events in humans. These serum cytokine elevations suggest activation of the stem cell mobilization mechanism in humans that results, as in mice, in accelerated atherosclerosis. Efforts to reduce CV disease in these patient populations should include mitigation of the diseases that trigger stem cell mobilization. Since activation of the stem cell up-regulation/mobilization mechanism appears to accelerate human atherosclerosis, use of stem cells as therapy for arterial occlusive disease should distinguish between direct administration of stem cells and activation of the stem cell up-regulation/mobilization mechanism.

Hypersplenism in liver disease and SLE revisited: current evidence supports an active rather than passive process

BACKGROUND

Active and passive theories have been advanced to explain splenomegaly and cytopenias in liver disease. Dameshek proposed active downregulation of hematopoiesis. Doan proposed passive trapping of blood components in a spleen enlarged by portal hypertension. Recent findings do not support a passive process.

DISCUSSION

Cytopenias and splenomegaly in both liver disease and systemic lupus erythematosus (SLE) poorly correlate with portal hypertension, and likely reflect an active process allocating stem cell resources in response to injury. Organ injury is repaired partly by bone-marrow-derived stem cells. Signaling would thus be needed to allocate resources between repair and routine marrow activities, hematologic and bone production. Granulocyte-colony stimulating factor (G-CSF) may play a central role: mobilizing stem cells, increasing spleen size and downregulating bone production. Serum G-CSF rises with liver injury, and is elevated in chronic liver disease and SLE. Signaling, not sequestration, likely accounts for splenomegaly and osteopenia in liver disease and SLE. The downregulation of a non-repair use of stem cells, bone production, suggests that repair efforts are prioritized. Other non-repair uses might be downregulated, namely hematologic production, as Dameshek proposed.

SUMMARY

Recognition that an active process may exist to allocate stem-cell resources would provide new approaches to diagnosis and treatment of cytopenias in liver disease, SLE and potentially other illnesses.

Analysis of Erythrocyte C4d to Complement Receptor 1 Ratio: Use in Distinguishing between Infection and Flare-Up in Febrile Patients with Systemic Lupus Erythematosus

Objective. Fever in systemic lupus erythematosus (SLE) can be caused by infection or flare-up of the disease. This study aimed to determine whether the ratio of the level of erythrocyte-bound C4d to that of complement receptor 1 (C4d/CR1) can serve as a useful biomarker in the differentiation between infection and flare-up in febrile SLE patients. Methods. We enrolled febrile SLE patients and determined the ratio on the day of admission. The patients were divided into 2 groups according to the subsequent clinical course. Results. Among the febrile SLE patients, those with flare-up had higher ratios and lower C-reactive protein (CRP) levels than those with infection. Cut-off values of <1.2447 and >4.67 for C4d/CR1 ratio and CRP, respectively, were 40.91% sensitive and 100.0% specific for the presence of infection in febrile SLE patients; similarly, cut-off values of >1.2447 and <2.2, respectively, were 80% sensitive and 100% specific for the absence of infection in febrile SLE patients. Conclusion. The C4d/CR1 ratio is a simple and quickly determinable biomarker that enables the differentiation between infection and flare-up in febrile SLE patients at initial evaluation. Further, when combined with the CRP level, it is useful to evaluate disease activity in SLE patients with infection.

Felty's Syndrome, Insights and Updates

Felty’s syndrome (FS) is characterized by the triad of seropositive rheumatoid arthritis (RA) with destructive joint involvement, splenomegaly and neutropenia. Current data shows that 1-3 % of RA patients are complicated with FS with an estimated prevalence of 10 per 100,000 populations. The complete triad is not an absolute requirement, but persistent neutropenia with an absolute neutrophil count (ANC) generally less than 1500/mm3 is necessary for establishing the diagnosis. Felty’s syndrome may be asymptomatic but serious local or systemic infections may be the first clue to the diagnosis. FS is easily overlooked by parallel diagnoses of Sjӧgren syndrome or systemic lupus erythematosus or lymphohematopoietic malignancies. The role of genetic (HLA DR4) is more prominent in FS in comparison to classic rheumatoid arthritis. There is large body of evidence that in FS patients, both cellular and humoral immune systems participate in neutrophil activation, and apoptosis and its adherence to endothelial cells in the spleen. It has been demonstrated that proinflammatory cytokines may have inhibitory effects on bone marrow granulopoiesis. Binding of IgGs to neutrophil extracellular chromatin traps (NET) leading to neutrophil death plays a crucial role in its pathophysiology. In turn, "Netting" neutrophils may activate auto-reactive B cells leading to further antibody and immune complex formation. In this review we discuss on basic pathophysiology, epidemiology, genetics, clinical, laboratory and treatment updates of Felty’s syndrome.

Autoimmune neutropenia

Autoimmune neutropenia (AIN) is a rare entity caused by antibodies directed against neutrophil-specific antigens. It includes primary and secondary autoimmune neutropenia. Acute autoimmune neutropenia can be related to drug-induced mechanism or viral infections. Chronic autoimmune neutropenias occur in the context of autoimmune diseases, hematological malignancies, such as large granular lymphocyte leukemia, primary immune deficiency syndromes or solid tumors. The therapeutic management depends on the etiology. Granulocyte growth factor is the main therapeutic option, raising the question of their long-term utilization safety. Corticosteroids or immunosuppressive therapy are indicated in infection-related AIN or in case of symptomatic autoimmune disease or LGL leukemia.

Management of autoimmune neutropenia in Felty's syndrome and systemic lupus erythematosus

Autoimmune neutropenia, caused by neutrophil-specific autoantibodies is a common phenomenon in autoimmune disorders such as Felty's syndrome and systemic lupus erythematosus. Felty's syndrome is associated with neutropenia and splenomegaly in seropositive rheumatoid arthritis which can be severe and with recurrent bacterial infections. Neutropenia is also common in systemic lupus erythematosus and it is included in the current systemic lupus classification criteria. The pathobiology of the autoimmune neutropenia in Felty's syndrome and systemic lupus erythematosus is complex, and it could be a major cause of morbidity and mortality due to increased risk of sepsis. Treatment should be individualized on the basis of patient's clinical situation, and prevention or treatment of the infection. Recombinant human granulocyte colony-stimulating factor is a safe and effective therapeutic modality in management of autoimmune neutropenia associated with Felty's syndrome and systemic lupus erythematosus, which stimulates neutrophil production. There is a slight increased risk of exacerbation of the underlying autoimmune disorder, and recombinant human granulocyte colony-stimulating factor dose and frequency should be adjusted at the lowest effective dose.

Significantly higher percentage of circulating CD27(high) plasma cells in systemic lupus erythematosus patients with infection than with disease flare-up

PURPOSE

To distinguish lupus flare-up from infection in systemic lupus erythematosus (SLE), we analyze the expression of circulating CD27(high) plasma cells in SLE patients with and without infection, in comparison to non-SLE patients with infection.

MATERIALS AND METHODS

The percentage of circulating CD27(high) plasma cells was measured by flow cytometry in the following four groups: 36 SLE patients without infection, 23 SLE patients with infection, eight non-SLE patients with infection, and 26 healthy controls.

RESULTS

The frequency of CD27(high) plasma cells had a correlation with the SLE disease activity index (SLEDAI) (r = 0.866, p < 0.05), level of anti-dsDNA (r = 0.886, p < 0.05), C3 (r = - 0.392, p < 0.05), and C4 (r = - 0.337, p < 0.05) in SLE patients without infection, but there was no correlation with disease activity in SLE patients with infection. Among three groups in particular-SLE without infection, SLE with infection, and non-SLE with infection- the percentages of CD27(high) plasma cells were elevated. The percentage of CD27(high) plasma cells was higher in SLE patients with infection, when compared to SLE patients without infection.

CONCLUSION

The percentage of CD27(high) plasma cells is a biomarker for disease activity of SLE without infection, under correlation with SLEDAI, anti-dsDNA, and C3 and C4 level. However, when the SLE patients have an infection, the percentage of CD27(high) plasma cells is not an adequate biomarker for the survey of disease activity. The percentage of CD27(high) plasma cells may serve as a potential parameter to distinguish a lupus flare-up from infection.

Diffuse disseminated candidiasis in a patient with Felty's syndrome: a case report

Severe granulocytopenia predispose patients with Felty's syndrome to severe infectious diseases. The following report deals with an occurrence of chronic disseminated candidiasis in a patient with Felty's syndrome who presented with prolonged and severe granulocytopenia. To the best of our knowledge this coexistence has never been described before.

Determination of ligand binding capacity of soluble Fc gamma RII and Fc gamma RIII in sera of patients with SLE

BACKGROUND

Soluble, human low affinity Fcgamma receptors, such as sFcgammaRII and sFcgammaRIII, are known to play a pathologic role in different diseases. Sandwich ELISAs had previously been applied for the specific detection and determination of these soluble receptors. In these ELISAs, commercial monoclonal antibodies (Ab) were used as capture antibodies with monoclonal or polyclonal antibodies serving as detector Abs. Increased levels of cell-free FcgammaRIII have been detected in patients with lupus but the functions and levels of sFcgammaRII have not been fully characterized yet.

OBJECTIVES

The aim of this work was to determine the ligand binding capacities and levels of soluble FcgammaRII and FcgammaRIII in sera of patients with systemic lupus erythematosus (SLE). Moreover, correlation between the levels of sFcgammaRII and sFcgammaRIII and the clinical activity of the disease were investigated.

METHODS

Sera of 47 patients with SLE, and 51 healthy subjects were analyzed. In the newly developed indirect sandwich ELISAs commercial monoclonal anti-FcgammaRs are used as capture antibodies, and the ligand of FcgammaRII and FcgammaRIII, an artificial immune complex (IC), serves as a detection component replacing the second antibodies used in previous methods.

RESULTS

The ligand binding capacity of both soluble FcgammaRII and sFcgammaRIII were elevated in the sera of SLE patients compared to control samples. This increase was significant in patients with the active disease (n = 30; p < 0.01). It was also revealed that a substantial part of the soluble Fcgamma receptors in these patients was bound in vivo to circulating IC.

CONCLUSION

These newly developed ELISAs are probably more phisiologically relevant than other previous assays because they detect the circulating receptors on the basis their in vitro ligan binding capacities. Therefore this method can separately measure the levels of the soluble, free FcgammaRs and those bound circulating IC in vivo.

Moderate and severe neutropenia in patients with systemic lupus erythematosus

OBJECTIVES

Neutropenia is an uncommon albeit relevant finding in patients with systemic lupus erythematosus (SLE). It has been ascribed to several aetiologies and represents a challenging dilemma in which clinical findings, laboratory data and medication history must be carefully evaluated. The aim of this work was to review the cases of moderate and severe neutropenia in our cohort of SLE patients in order to identify predisposing factors, clinical outcomes and related prognostic implications.

METHODS

Thirty-three cases of neutropenia (neutrophil count <1000/microl) in patients with SLE were included. Sixty-five age- and sex-matched patients with SLE served as controls. Information was obtained by medical chart review. Statistical analyses included descriptive statistics, Student's t-test, paired t-test, chi 2 or Fisher's exact test, and logistic regression.

RESULTS

Baseline characteristics did not differ between groups. Use of concomitant medications and immunosuppressive drugs, as well as history of thrombocytopenia and central nervous system involvement, were associated with an increased risk for developing neutropenia. Along with neutropenia, cases had lower haemoglobin and platelet values and higher levels of liver enzymes. Moreover, disease activity was lower than in controls. One month after the neutropenia event, leucocyte and total granulocyte counts were still lower in patients than in controls. Mortality did not differ between patients with neutropenia and controls.

CONCLUSIONS

Most episodes of severe granulocytopenia in SLE patients occur as part of drug toxicity-induced medullar hypoplasia.

Infections and SLE

Viral and bacterial infections may serve as an environmental trigger for the development or exacerbation of systemic lupus erythematosus (SLE) in the genetically predetermined individual. In addition, SLE patients are more prone to develop common (pneumonia, urinary tract infection, cellulitis, sepsis), chronic (tuberculosis), and opportunistic infections possibly due to inherit genetic and immunologic defects (complement deficiencies, mannose-binding lectin [MBL] polymorphisms, elevated Fcgamma III and GM-CSF levels, osteopontion polymorphism), but also due to the broad spectrum immunosuppressive agents that are part of therapy for severe manifestations of the disease. Hence, SLE patients are considered a high-risk population, where identification and treatment of chronic infections such as tuberculosis, hepatitis B or human immunodeficiency virus, are important prior to the institution of immunosuppression so as to prevent reactivation or exacerbation of the infection. Infections in SLE patients remain a source of morbidity and mortality. A caveat often encountered is to distinguish between a lupus flare and an acute infection; in such cases parameters including elevated CRP (and adhesion molecules) may aid in the diagnosis of infection. Recent research has provided convincing evidence that EBV infection may play a major role not only in molecular mimicry but also in aberrations of B cells and apoptosis leading to a state of perpetual heightened immune response in SLE.

Proteomic signature of myeloproliferation and neutrophilia: analysis of serum and plasma from healthy subjects given granulocyte colony-stimulating factor

OBJECTIVE

Proteomic analysis could improve our understanding of the mechanisms and consequences of myeloproliferation. Healthy subjects treated with granulocyte colony-stimulating factor (G-CSF) were used as a model of myeloproliferation.

METHODS

Levels of 80 soluble factors were measured by enzyme-linked immunosorbent assay before and after 5 days of G-CSF. Both serum and plasma levels were measured to generate a comprehensive profile and determine whether serum or plasma best portrays biological and physiological changes.

RESULTS

Comparison of samples collected prior to G-CSF demonstrated that 44 factors differed between serum and plasma. Concentrations of several growth factors and chemokines were greater in serum than in plasma, while the opposite was true for several interleukins. Following G-CSF serum levels of 14 factors and plasma levels of 15 factors changed. Eleven increased in both serum and plasma, including cell adhesion molecules (vascular cell adhesion molecule-1, E-selectin, and L-selectin), matrix metalloproteases (MMP-1, -8, and -13), cytokine receptors (tumor necrosis factor receptor 1 and 2, and interleukin-2 receptor), the acute phase reactant, serum amyloid A, and a growth factor, hepatocyte growth factor.

CONCLUSION

Some protein levels differ markedly in serum and plasma. Myeloproliferation is associated with changes in the levels of several proteases, adhesion molecules, and cytokines.

[Early diagnosis of chronic systemic inflammatory disorders]

Functionally relevant damage caused by chronic systemic inflammatory disorders of autoimmune and/or unknown origin can be reduced or sometimes avoided by early initiation of treatment. This requires a correct diagnosis which makes treatment as early as possible. Due to the often uncharacteristic symptoms at the onset of disease, early diagnosis in systemic inflammatory disorders represents a diagnostic challenge. This review outlines current standards and limitations in the early diagnosis of rheumatoid arthritis, collagen vascular diseases and primary systemic vasculitides. Recent advances especially in serology and imaging techniques have improved early diagnosis of systemic inflammatory disorders.

Autoantibodies against granulocyte-macrophage colony stimulating factor and interleukin-3 are rare in patients with Felty's syndrome

OBJECTIVES

Antibodies against granulocyte colony stimulating factor are frequently found in patients with Felty's syndrome (FS). In this study, we examined the prevalence of antibodies against two other granulopoietic cytokines: granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-3 (IL3).

METHODS

Sera of 32 patients with FS, 20 normocytic patients with rheumatoid arthritis (RA), and 72 healthy individuals were screened for the presence of antibodies against GM-CSF and IL3 by ELISA and bioassays, using the human erythroleukaemia cell line TF-1.

RESULTS

In two of the 32 patients with FS, antibodies to GM-CSF and IL3 were detectable by ELISA. Binding anti-GM-CSF antibodies were also detected in one of the 72 healthy controls, while in another healthy subject and in one of the patients with normocytic RA, anti-IL3 antibodies were present. Serum from one of the two patients with FS who tested positive for anti-IL3 and anti-GM-CSF antibodies by ELISA showed strong neutralising capacity to the biological effect of IL3, but not to GM-CSF in vitro. Patients with FS had significantly higher serum levels of GM-CSF (median; 2.82 pg/mL; interquartile range 2.64-3.19 pg/mL) compared with patients with RA (2.52 pg/mL; 2.28-2.72 pg/mL; p = 0.012) and healthy controls (2.23 pg/mL; 2.04-2.52; p<0.001). In addition, serum levels of IL3 in patients were significantly higher in FS (10.05 pg/mL; 8.94-11.98) compared with controls (4.79 pg/mL; 3.72-7.22; p<0.001), but not compared with RA patients (9.52 pg/mL; 8.32-10.42; p = 0.17).

CONCLUSIONS

Antibodies to GM-CSF and IL3 are rare in patients with FS and RA and in healthy subjects. In individual patients with FS, the presence of neutralising anti-IL3 antibodies may contribute to the development of cytopenia.

TNF-related apoptosis-inducing ligand is involved in neutropenia of systemic lupus erythematosus

Neutropenia is a common laboratory finding in systemic lupus erythematosus (SLE). However, the molecular mechanism of SLE neutropenia has not been fully explained. In this study, we examined whether TNF-related apoptosis-inducing ligand (TRAIL) is involved in the pathogenesis of SLE neutropenia using samples from SLE patients. Serum TRAIL levels in SLE patients with neutropenia were significantly higher than those of SLE patients without neutropenia and healthy volunteers. Serum TRAIL levels showed a significant negative correlation with neutrophil counts in SLE patients. The expression of TRAIL receptor 3 was significantly lower in SLE patients with neutropenia than in patients without neutropenia or in healthy volunteers. Treatment with glucocorticoids negated the decrease of TRAIL receptor 3 expression on neutrophils of SLE patients. TRAIL may accelerate neutrophil apoptosis of neutrophils from SLE patients, and autologous T cells of SLE patients, which express TRAIL on surface, may kill autologous neutrophils. Interferon gamma and glucocorticoid modulated the expression of TRAIL on T cells of SLE patients and also modulated the expression of cellular Fas-associating protein with death domain–like interleukin-1β–converting enzyme (FLICE)–inhibitory protein (cFLIP), an inhibitor of death receptor signaling, in neutrophils. Thus, our results provide a novel insight into the molecular pathogenesis of SLE neutropenia.

SLE and infections

Infections are common in systemic lupus erythematosus (SLE), and remain a source of mortality. The types of infections (such as pneumonia, urinary tract infection, cellulitis, and sepsis) in SLE patients are similar to the general population and include the same pathogens (Gram-positive and Gram-negative). SLE patients may also develop opportunistic infections, especially when treated with immunosuppressive agents. As a high-risk population, identification and treatment of chronic infections such as tuberculosis, hepatitis B, or human immunodeficiency virus (HIV), are important prior to the institution of immunosuppression to prevent reactivation or exacerbation of the infection. A common caveat is to distinguish between a lupus flare and an acute infection; judicious use of corticosteroids and cytotoxic drugs is critical in limiting infectious complications. The risk factors associated with susceptibility to disease include severe flares, active renal disease, treatment with moderate or high doses of corticosteroids and/or immunosuppressive agents, and others. Genetic factors (complement deficiencies, mannose-binding lectin, Fcgamma III, granulocyte macrophage colony-stimulating factor [GM-CSF], osteopontin) may predispose certain SLE patients to develop infections. Parameters including C-reactive protein (CRP) and adhesion molecules may help to differentiate an infectious disease from an exacerbation of the disease. Finally, the mechanism of molecular mimicry by specific microbial agents may play a role in the induction of SLE.