The diagnostic values of C-reactive protein and procalcitonin in identifying systemic lupus erythematosus infection and disease activity

Evaluation of disease activity in systemic lupus erythematosus using standard deviation of lymphocyte volume combined with red blood cell count and lymphocyte percentage

Systemic lupus erythematosus (SLE) commonly damages the blood system and often manifests as blood cell abnormalities. The performance of biomarkers for predicting SLE activity still requires further improvement. This study aimed to analyze blood cell parameters to identify key indicators for a SLE activity prediction model. Clinical data of 138 patients with SLE (high activity, n = 40; moderate activity, n = 44; mild activity, n = 37; low activity, n = 17) and 100 healthy controls (HCs) were retrospectively analyzed. Data from 89 paired admission-discharge patients with SLE were collected. Differences and associations between blood cell parameters and disease indicators, as well as the relationship between the these parameters and organ damage, were examined. Machine-learning methods were employed to develop a prediction model for disease activity evaluation. Most blood cell parameters (22/26, 84.62%) differed significantly between patients with SLE and HCs. Analysis of 89 paired patients with SLE revealed significant changes in most blood cell parameters at discharge. The standard deviation of lymphocyte volume (SD-V-LY), red blood cell (RBC) count, lymphocyte percentage (LY%), hemoglobin(HGB), hematocrit(HCT), and neutrophil percentage(NE%) correlated with disease activity. By employing machine learning, an optimal model was established to predict active SLE using SD-V-LY, RBC count, and LY% (area under the curve [AUC] = 0.908, sensitivity = 0.811). External validation indicated impressive performance (AUC = 0.940, sensitivity = 0.833). Correlation analysis revealed that SD-V-LY was positively correlated with ESR, IgG, IgA, and IgM but was negatively correlated with C3 and C4. The RBC count was linked to renal and hematopoietic system impairments, whereas LY% was associated with joint/muscle involvement. In conclusion, SD-V-LY is associated with SLE disease activity. SD-V-LY combined with RBC count and LY% contributes to a prediction model, which can be utilized as an effective tool for assessing SLE activity.

Infection versus disease activity in systemic lupus erythematosus patients with fever

BACKGROUND

to detect the role of procalcitonin, erythrocyte sedimentation rate to c-reactive protein (ESR/CRP) ratio, neutrophils-to-lymphocyte ratio (NLR), and platelets-to-lymphocyte ratio (PLR) in the diagnosis of infection in systemic lupus erythematosus (SLE) patients with fever, their diagnostic value to differentiate between infection and disease activity, and their correlation with disease activity.

METHODS

Forty SLE patients and forty healthy control cases were included in the study. Disease activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K), and quality of life was assessed by Lupus QoL. A bacterial infection was detected by clinical symptoms and positive culture results. Laboratory tests were done for all patients and controls: complete blood count (CBC), ESR, CRP, and procalcitonin (PCT). NLR, PLR, and ESR/CRP ratios were calculated.

RESULTS

There was a statistically significant difference between infected SLE patients and non-infected SLE patients regarding PCT (p < 0.001), ESR (p = 0.002), CRP (p = 0.005), ESR/CRP ratio (0.002), and NLR (p = 0.023). PCT, ESR, CRP, and NLR were positively correlated with the presence of infection in SLE patients, while the ESR/CRP ratio was negatively correlated. There was no significant correlation with the SLEDAI-2 K score. Logistic regression analysis revealed that PCT was the best significant predictor of infection (OR 224.37, 95% CI 8.94-5631.35). PCT was a good predictor of infection, with a cut-off value of 0.90 ng/ml, which gave the best combination of sensitivity (84.62%) and specificity (85.71%).

CONCLUSION

PCT, ESR/CRP ratio, and NLR provide good diagnostic markers for the diagnosis of infection and can distinguish between infection and disease flare in SLE patients with fever.

Prognosis prediction of procalcitonin within 24 h for acute diquat poisoning

BACKGROUND

To explore the predictive value of procalcitonin (PCT) within 24 h after poisoning for prognosis of acute diquat poisoning.

METHODS

This retrospective study included acute diquat poisoning patients in the Nanyang City Hospital between May 2017 and July 2021.

RESULTS

Among the 45 patients included, 27 survived. The maximum PCT value within 24 h after poisoning was significantly higher in the non-survival patients [9.65 (2.63, 22.77) vs. 0.15 (0.10, 0.50) µg/mL, P < 0.001] compared to the survival patients. The area under the ROC curve (AUC) indicated that the maximum PCT value within 24 h had a good predictive value (AUC = 0.905, 95% CI: 0.808-1.000) compared to ingested quantity (AUC = 0.879, 95% CI: 0.776-0.981), serum creatinine (AUC = 0.776, 95% CI: 0.640-0.912), or APACHE II score (AUC = 0.778, 95% CI: 0.631-0.925). The predictive value of maximum PCT value within 24 h was comparable with blood lactate (AUC = 0.904, 95%CI: 0.807-1.000).

CONCLUSIONS

The maximum PCT value within 24 h after poisoning might be a good predictor for the prognosis of patients with acute diquat poisoning.

Recurrent Temporal Infections: The Link to Systemic Lupus Erythematosus

BACKGROUND Systemic lupus erythematosus (SLE) is an autoimmune disease with diverse manifestations. The involvement of the musculoskeletal system is very common, and infection is one of the manifestations, which can involve any part of the body. We report a case of a middle-aged woman with recurrent episodes of infection of her left temple. CASE REPORT A 51-year old woman was referred to our clinic following failures to eradicate infection on her left temple for 9 months. Examination revealed facial asymmetry, with diffuse non-tender swelling involving her left temple area, which extended to her cheek. Computed tomography and magnetic resonance imaging (MRI) showed a periosteal reaction of the zygomatic bone. Left temporalis muscle thickening and residual osteomyelitis of the zygomatic bone were also shown by MRI. In view of the unresolved infection with incision and drainage and antibiotics, further blood investigations led to the discovery of SLE. The antinuclear antibody and anti-double-stranded DNA were positive. In addition, low nephelometry markers, C3 (26.7 mg/dL) and C4 (8.24 mg/dL), were observed. This patient was treated with 200 mg of oral hydrochloroquine once daily and 5 mg of oral prednisolone once daily. After 6 months of treatment, the infection subsided, and the structures involved showed remarkable healing. The patient is still taking the same dose and frequency of both drugs at the present time. CONCLUSIONS Temporalis pyomyositis and osteomyelitis of the zygomatic bone could be manifestation of SLE disease; however, the involvement of infection cannot be ruled out.

Diagnostic value of serum procalcitonin and C-reactive protein in discriminating between bacterial and nonbacterial colitis: a retrospective study

BACKGROUND

Differentiating between bacterial and nonbacterial colitis remains a challenge. We aimed to evaluate the value of serum procalcitonin (PCT) and C-reactive protein (CRP) in differentiating between bacterial and nonbacterial colitis.

METHODS

Adult patients with three or more episodes of watery diarrhea and colitis symptoms within 14 days of a hospital visit were eligible for this study. The patients' stool pathogen polymerase chain reaction (PCR) testing results, serum PCT levels, and serum CRP levels were analyzed retrospectively. Patients were divided into bacterial and nonbacterial colitis groups according to their PCR. The laboratory data were compared between the two groups. The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic accuracy.

RESULTS

In total, 636 patients were included; 186 in the bacterial colitis group and 450 in the nonbacterial colitis group. In the bacterial colitis group, Clostridium perfringens was the commonest pathogen (n=70), followed by Clostridium difficile toxin B (n=60). The AUC for PCT and CRP was 0.557 and 0.567, respectively, indicating poor discrimination. The sensitivity and specificity for diagnosing bacterial colitis were 54.8% and 52.6% for PCT, and 52.2% and 54.2% for CRP, respectively. Combining PCT and CRP measurements did not increase the discrimination performance (AUC, 0.522; 95% confidence interval, 0.474-0.571).

CONCLUSION

Neither PCT nor CRP helped discriminate bacterial colitis from nonbacterial colitis.

Biosensors; noninvasive method in detection of C-reactive protein (CRP)

Early diagnosis of C reactive protein (CRP) is critical to applying effective therapies for related diseases. Diagnostic technology in today's healthcare systems is mostly deployed in central laboratories, involves expensive and time-consuming processes, and is operated by specialized personnel. For example, the enzyme-linked immunosorbent assay (ELISA), considered the gold standard diagnostic method, is labor-intensive and requires complex procedures such as multiple washing and labeling steps. Due to these limitations of current diagnostic techniques, it is difficult for people to regularly monitor their health and ultimately the disease is more likely to be diagnosed at a later stage. The problem is exacerbated for economically disadvantaged people living in underdeveloped countries. To address these challenges in the traditional diagnostic field, point-of-care (POC) biosensors have emerged as a promising alternative. This allows patients to have their health checked regularly at or near their bedside without resorting to laboratory tests. Nanotechnology-based methods such as biosensors have been extensively researched and developed. Among biosensors, there are also label-free biosensors with high sensitivity that do not require complicated procedures and reduce test time. However, some drawbacks such as high cost, bulky size and need for trained personnel to operate have not been improved. In this review article, we provide an overview of routine methods in CRP diagnosis and then introduce biosensors as a modern, advanced alternative to older methods. Readers of this article can learn about biosensing and its benefits while being aware of the limitations of routine methods.

The Inflammatory Profile Orchestrated by Inducible Nitric Oxide Synthase in Systemic Lupus Erythematosus

(1) Background: The pathogenesis of systemic lupus erythematosus (SLE) involves complicated and multifactorial interactions. Inducible nitric oxide synthase overactivation (iNOS or NOS2) could be involved in SLE pathogenesis and progression. This study explored the relationship between NOS2-associated inflammation profiles and SLE phenotypes. (2) Methods: We developed a prospective, case control study that included a group of 86 SLE subjects, a group of 73 subjects with lupus nephritis, and a control group of 60 people. Laboratory determinations included serum C reactive protein (CRP-mg/L), enzymatic activity of NOS2 (U/L), serum levels of inducible factors of hypoxia 1 and 2 (HIF1a-ng/mL, HIF2a-ng/mL), vascular endothelial growth factor VEGF (pg/mL), matrix metalloproteinases 2 and 9 (MMP-2, MMP-9-ng/mL), thrombospondin 1 (TSP-1-ng/mL), and soluble receptor of VEGF (sVEGFR-ng/mL). (3) Results: CRP, NOS2, HIF-1a, HIF-2a, VEGF, MMP-2, and MMP-9 were significantly increased, while TSP-1 and sVEGFR were decreased in the SLE and lupus nephritis groups compared with the control group. The variations in these biomarkers were strongly associated with the decrease in eGFR and increase in albuminuria. (4) Conclusions: The inflammatory phenotype of SLE patients, with or without LN, is defined by NOS2 and hypoxia over-expression, angiogenesis stimulation, and inactivation of factors that induce resolution of inflammation in relation with eGFR decline.

A Challenging Diagnosis of Febrile Pancytopenia in a Patient With a History of Autoimmune Disease

Pancytopenia is a hematologic condition characterized by a decrease in all three peripheral blood cell lines. There are many causes of pancytopenia, and the proper approach is required for accurate diagnosis. Brucellosis and systemic lupus erythematosus (SLE) are both diseases that can initially present as pancytopenia, both of which require a targeted workup to diagnose. Due to the immune system's complexity, many distinct diseases may have similar symptomatology. Furthermore, infections and rheumatological diseases can stimulate the same molecular pathways and trigger T and B cells. This creates a cross-reactivity between microbial peptides and self-peptides, allowing the spread of microbial-specific T cells that can also respond to self-peptides. Brucellosis has broad clinical manifestations, often mimicking many other diseases, such as rheumatoid arthritis, sarcoidosis, and SLE. In addition, brucellosis-induced autoantibody production has been described as a triggering factor for immunologic reactions, elevating rheumatological markers by a poorly understood mechanism. Finally, SLE is a well-known medical condition that can mimic several medical conditions, including brucellosis.  We present a case of a young patient who was admitted with febrile pancytopenia. The patient also had IgM antibodies positive for brucellosis and high immune markers for SLE. She was treated for both diseases, and afterward, in retrospect, it was confirmed that the patient did not have acute brucellosis.

Clinical features and markers to identify pulmonary lesions caused by infection or vasculitis in AAV patients

OBJECTIVES

Pulmonary lesion is frequently seen in ANCA-associated vasculitis (AAV) patients primarily due to AAV lung involvement or infection, which are hard to differentiate due to their high similarity in clinical manifestations. We aimed to analyze the clinical features of pulmonary lesions consequent to AAV involvement or infection in AAV patients and further identify the markers for differential diagnosis.

METHODS

140 AAV patients who admitted to the Renmin Hospital of Wuhan University from January 2016 to July 2021 were included in this study. According to the nature of lung conditions, these patients were divided into the non-pulmonary lesion group, the lung infection group and the non-pulmonary infection group, and their demographics, clinical symptoms, imaging features, as well as laboratory findings were compared. A receiver operating characteristic (ROC) curve was drawn, and the diagnostic efficacy of single biomarker and composite biomarkers on pulmonary infection was then evaluated.

RESULTS

The patients in the lung infection group were significantly older than those in the no lesion group (63.19 ± 14.55 vs 54.82 ± 15.08, p = 0.022). Patients in the lung infection group presented more frequent symptoms and more obvious pulmonary image findings. Compared with patients in the non-pulmonary infection group, patients in the lung infection group showed a higher symptom incidence of fever, chest tightness, cough and expectoration, and hemoptysis (52.94% vs 16.00%, 61.76% vs 40.00%, 72.06% vs 46.00%, 27.94% vs 8.00%, p < 0.05, respectively), and more changes in pulmonary CT scanning images in terms of patched/striped compact opacity, alveolar hemorrhage, bronchiectasis, pleural effusion, as well as mediastinal lymphadenopathy (89.71% vs 52.00%, 11.76% vs 2.00%, 22.06% vs 8.00%, 50.00% vs 20.00%, 48.53% vs 24.00%, p < 0.05, respectively). In addition, patients in the lung infection group had significantly higher levels of serum pro-calcitonin (PCT), C-reactive protein (CRP), amyloid A (SAA), blood neutrophil-to-lymphocyte ratio (NLCR), erythrocyte sedimentation rate (ESR), as well as Birmingham vasculitis activity score (BVAS) than patients in the other two groups (p < 0.05). Among all biomarkers, PCT exhibited the highest diagnostic efficacy (0.928; 95%CI 0.89-0.97) for pulmonary infected AAV patients at a cut-off score of 0.235 ng/ml with 85.3% sensitivity and 84% specificity. Moreover, the composite biomarker of PCT-CRP-NLCR showed more diagnostic efficacy (0.979; 95% CI 0.95-1.00) in distinguishing the infectious and non-infectious lung injuries in AAV patients.

CONCLUSIONS

AAV patients with lung infection manifested more clinical symptoms and prominent lung image changes. The PCT and composite biomarker PCT-CRP-NLCR showed high diagnostic efficacy for a lung infection in AAV patients. Pulmonary lesion caused by either infection or AAV involvement is commonly seen and difficult to distinguish. We aim to identify the biomarkers that can be applied in the differentiation diagnosis of pulmonary lesions in AAV patients.

Risk factors analysis and risk assessment model construction of systemic lupus erythematosus patients with infection

OBJECTIVE

To analyze the characteristics of peripheral blood lymphocyte subsets in systemic lupus erythematosus (SLE) patients with infection and non-infection group. Explore the risk factors of infection in SLE patients and establish a risk matrix model to predict the occurrence of co-infection.

METHODS

total of 333 SLE patients without infection, 163 patients suffering from infection, and 132 healthy controls (HCs) were recruited. General clinical data and disease activity indicators were collected. The levels of total T, B, CD4⁺T, CD8⁺T, NK, Th1, Th2, Th17, and Treg cells in peripheral blood of HCs, SLE patients (including infected and non-infected group) were analyzed by flow cytometry. The risk assessment model was constructed, and the receiver operating characteristic curve was drawn. 39 SLE patients with infection and 20 patients without infection were randomly selected to evaluate the predictive power of the regression model.

RESULTS

The levels of T, B, CD4⁺T, CD8⁺T, and NK cells in the infected patients were significantly decreased when compared with that of both non-infected patients and HCs (p < .05). The non-infected patients had a higher level of Th17 than that of HCs (p < . 05), but the absolute numbers of Th17 in infected patients was the lowest among the three groups (p < .001). The number of Treg cells in SLE patients was significantly lower than that of HCs (p < .01), and the infected patients had the fewest Treg cells among all these groups (p < . 05). A risk assessment model for SLE with infection was established, p = 1/(1^-e^-y), Y = 1.763-0.004 × Absolute number of CD4 ⁺ T cells-0.005 × Absolute number of NK cells -0.005 × Platelet count(×10¹²/L) + 1.033 × Absolute number of lymphocytes (×10⁹/L) + 0.023 × C-reactive protein (mg/dL), whose predictive sensitivity is 77.5%, and specificity is 78.3%.

CONCLUSION

The new risk assessment model exhibits good predictive ability to assess co-infection risk in SLE patients. T cells, NK cells, and CD4 ⁺ T cells along with other parameters help in differentiating Lupus with infection from Lupus alone.

Characterization of Pediatric Patients with Rheumatological Diseases Admitted to a Single Tertiary Health Hospital's Pediatric Intensive Care Unit in Latin America

Most autoimmune diseases (AIDs) during childhood debut with more severe and aggressive forms, with life-threatening conditions that increase the need for intensive care therapy. This study describes the clinical, laboratory, and health outcome features of pediatric patients with AIDs admitted to the pediatric intensive care unit (PICU). This is a retrospective cross-sectional study that included the clinical records of all pediatric patients with AIDs admitted to the PICU between 2011 and 2020 in Cali, Colombia. In total, 225 PICU admissions from 136 patients were evaluated. Median age was 13 (11–15) years, and the median disease duration was 15 (5–38.5) months. Systemic lupus erythematosus was the most prevalent disease (91, 66.9%), followed by vasculitis (27, 19.8%). The leading cause of PICU admission was AID activity (95, 44.3%). C-reactive-protein levels were associated with infections (p <0.0394). Mortality occurred in 12 (8.8%) patients secondary to AID activity, primarily, diffuse alveolar hemorrhage (6, 50%). A longer disease duration was associated with mortality (p <0.00398). AID activity was the leading cause of PICU admission and mortality. Pulse steroid therapy, mechanical ventilation, and inotropic and vasopressor support were associated with nonsurvival.

Differentiating flare and infection in febrile lupus patients: Derivation and validation of a calculator for resource constrained settings

Background: Patients with Systemic Lupus Erythematous (SLE) are at an increased risk of infection and it is often difficult to differentiate between infection and disease activity in a febrile patient with SLE. Methods: Patients with SLE (SLICC criteria) presenting with fever between December 2018 and August 2021 were included. Neutrophil to lymphocyte ratio (NLR), NEUT-x, -y, -z indices, Erythrocyte sedimentation rate (ESR), C-reactive protein(CRP), C3, C4, anti-dsDNA antibodies, and procalcitonin(PCT) were tested in addition to investigations as per the treating physician's discretion. Based on the clinical assessment and laboratory data, the febrile episode was classified into infection, disease flare, or both. Statistical analysis was done using GraphPad prism v8.4.2. A novel composite score was devised and validated with a calculator incorporated is a spreadsheet. The performance of a previously proposed model of duration of fever, CRP, and dsDNA (Beca et al) was evaluated and other models using PCT and NEUT-Z were explored. Results: Among 168 febrile episodes in 166 patients with SLE (25 (19-32) years), 46 were due to infection, 77 due to flare, 43 due to both, and two due to other causes. High SLEDAI 2K (0.001), anti-dsDNA (p = 0.004), and low complements(C3, p = 0.001 and C4, p = 0.001) were characteristic of disease flare, whereas high total leukocyte count (TLC) (p = 0.008), NLR (p = 0.008), NEUT-x (p = 0.001), -y (p = 0.03), -z (p = 0.002), CRP (p = 0.001), and PCT (p = 0.03) were observed with infection. A model using age, TLC, and CRP was devised using 80% of the cohort with an AUC of 0.88 (0.78-0.97) which was validated in the remaining 20% to have an AUC of 0.83(0.60-1.0). The model devised by Beca et al yielded an AUC of 0.74. Use of PCT did not improve the discrimination between flare and infection. A Model of C4 and NEUT-z analyzed in a subset performed well and needs further exploration. Conclusion: A composite score of low cost and routinely available parameters like age, TLC, and CRP gives a good discrimination between infection and flare in a febrile patient with SLE.

Low-dose IL-2 therapy limits the reduction in absolute numbers of peripheral lymphocytes in systemic lupus erythematosus patients with infection

BACKGROUND

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disorder characterized by disturbed cellular and humoral immune responses. Dysregulations of immune system and immunosuppressive medications predispose SLE patients to infection. This study aims to investigate the alterations and absolute concentrations of lymphocyte subpopulations in SLE patients with different infection and their responses of low-dose IL-2 therapy.

METHODS

A total of 333 patients with SLE without recent infection, 162 patients suffering infection, and age and sex-matched 132 healthy controls (HCs) were recruited. Of them, 54 SLE patients (including 41 non-infected group and 13 infected group) received a 5-day course of low-dose IL-2 administration at a dose of 0.5 million IU per day. Lymphocyte subpopulations were analyzed by flow cytometry.

RESULTS

Patients with SLE had lower levels of lymphocyte subpopulations in peripheral blood such as T, B, NK, CD4 + T, CD8+ T, Th1, Th2, Th17, and Treg cells, and the reduction in these cells was more obvious in patients with infection (p <.05 to p <.01). Low-dose IL-2 effectively expanded T (p <.001), B (p <.001), CD4 + T (p <.01), CD8 + T (p <.001), Th1 (p <.01), Th17 (p <.1), and Treg cells (p <.01) of SLE patients, these cells were comparable to that of HCs after the IL-2 treatment.

CONCLUSIONS

Patients with SLE had insufficiency of circulating lymphocyte subsets. This phenomenon was more obverse in those accompanying infection, suggesting the low concentration of lymphocytes may be used as indicators of high infection risk in SLE patients. Low-dose IL-2 induced expansion of Treg cells and NK cells, which may contribute to the restoration of immune homeostasis in SLE patients.

The utility of erythrocyte sedimentation rate, C-reactive protein, and procalcitonin in detecting infections in patients with systemic lupus erythematosus: A systematic review

OBJECTIVES

We conducted a systematic review with metanalysis to investigate the utility of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and procalcitonin (PCT) in diagnosing infections in hospitalized patients with SLE.

METHODS

We searched Medline, Embase, Web of Science, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials (CENTRAL) with a search strategy developed by a medical librarian. We included retrospective, cross-sectional, case-control, and prospective studies in our analysis. We used the Quality Assessment of Diagnostic Studies (QUADAS-2) to assess for bias and applicability. We obtained mean differences, sensitivities, and specificities in our analysis.

RESULTS

We included 26 studies in our analysis. Most studies had an unclear or high risk of bias and our results were widely heterogenous. For the diagnosis of infections, the CRP had a pooled sensitivity of 0.75 (95%CI 0.57-0.94) and specificity of 0.72 (0.59-0.85), PCT had a pooled sensitivity of 0.68 (95% CI 0.0.59-0.77) and specificity of 0.75 (0.59-0.90), and for ESR pooled estimates were not calculated but sensitivity ranged from 50 to 69.8 and specificity from 38.5 to 55.6. Modifying cut-offs improved sensitivities and specificities. The ESR, CRP, and PCT mean differences were all greater in infection groups versus non-infection (10.1, 95% CI 3.2-17.0; 46.8, 95% CI 36.5-57.0; 0.53, 95% CI 0.26-0.80; respectively).

DISCUSSION

Poor sensitivities and specificities were observed for the evaluated biomarkers with substantial heterogeneity in the cut-offs used to determine infection. Although mean biomarker values were increased in the infection group compared with the non-infection, our findings do not support the widespread use of ESR, CRP, or PCT in diagnosing infection in hospitalized patients with SLE due to increased heterogeneity and risk of bias. Further investigation is needed.

Pattern of change of C-reactive protein levels and its clinical implication in patients with acute poisoning

Objectives:

C-reactive protein is well known as an inflammatory indicator in injury, infection, and cancer. However, little is known about its role in poisoning. C-reactive protein levels first increase and then decrease within several days during poisoning management. This study aimed to verify the C-reactive protein change pattern and its clinical co-infection possibility in patients with poisoning.

Methods:

Daily C-reactive protein levels of the patients with poisoning, who were admitted for more than 5 days, were measured. Microbial cultures were conducted, and fever (⩾38°C) and infection-related symptoms were investigated.

Results:

In the enrolled 56 patients, the initial median C-reactive protein levels at hospital day 1, 2, 3, 4, and 5 were 0.28, 4.85, 10.91, 10.57, and 6.68 mg/dL, respectively. C-reactive protein level was the highest at hospital day 3 and decreased thereafter. No statistical difference was observed in the daily and maximal C-reactive protein levels between the culture-positive and culture-negative groups. The levels at hospital days 3–5 and the maximal level were 8.4, 9.2, 5.49, and 11.02 mg/dL, respectively, in non-fever group. The levels at hospital days 3–5 and the maximal level were 7.4, 9.2, 4.74, and 10.81 mg/dL, respectively, in non-symptoms group. Levels at hospital days 3–5 and the maximal level were 5.21, 4.93, 3.7, and 5.28 mg/dL, respectively, in all-negative (culture-negative without fever or infection symptoms) group.

Conclusions:

Acute rise and fall of C-reactive protein levels can be observed in the infection-unlikely patients with poisoning. The levels were similar to bacterial infection levels, possibly due to the drug reaction itself, rather than for superimposed infections.

Performance of Procalcitonin to Distinguish Fungal from Bacterial Infections in Patients with Systemic Lupus Erythematosus

Purpose

To evaluate the performance of serum procalcitonin (PCT) concentrations to diagnose fungal infection in patients with systemic lupus erythematosus (SLE).

Patients and Methods

From January 2017 to October 2020, SLE patients hospitalized for serious infection with an identified single bacterial or fungal pathogen, as well as PCT measured within 24h after admission were included. The diagnostic performance of PCT was evaluated independently and in combination with the white blood cell (WBC) count, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR). The analysis included the sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, and the crude and adjusted area under the receiver operating characteristic curve (AUROC).

Results

Sixty-nine patients were included; 26 had a fungal infection (38%) and 43 had a bacterial infection (22 gram-positive and 21 gram-negative). Fungal infection patients were mainly distributed in the respiratory group (88.5%), and bacterial infection distribution were more prevalent in respiratory group (44.2%) and abdominal/urinary group (23.3%). The PCT concentration was significantly lower in fungal infections than bacterial infections (fungal: 0.22 ng/mL, interquartile range [IQR], 0.09-0.44 vs bacterial: 0.60 ng/mL, IQR, 0.16-5.74; p = 0.016) and differed significantly between different infection sites (p = 0.022). PCT had better diagnostic performance for predicting fungal infection (AUROC = 0.731) than the WBC count (AUROC = 0.581), the CRP level (AUROC = 0.716), and ESR (AUROC = 0.583). PCT and ESR together had the best diagnostic performance, with 46.2% sensitivity and 88.4% specificity. Further, the AUROC increased compared to PCT alone but was statistically insignificant (p = 0.693).

Conclusion

For SLE patients with serious infection, the PCT concentration had better diagnostic accuracy for predicting fungal infection than the WBC count, the CRP level, and ESR. Combining PCT and ESR obtained the highest AUROC and provided an acceptable discrimination performance.

Recurrent lupus enteritis in a child-chase the calm before the storm

Systemic lupus erythematosus (SLE) is a complex multisystemic autoimmune disease. Lupus enteritis (LE), one of the less commonly described manifestations of childhood SLE, presents with relatively nonspecific clinical and laboratory features. In addition, recurrent episodes of LE occurring in temporal proximity are rare in children. Presence of disease activity at other sites (which may not be seen universally) supports the diagnosis of LE in an appropriate setting. Because of its potential role to cause ischemic complications, early recognition and prompt treatment are necessary for a good outcome. Herein, we describe a child with recurrent LE with an interval of about 3 months between the first and the second episode. The first episode correlated with systemic disease activity and bowel thickening was noted on abdominal ultrasonography. This episode was successfully managed with intravenous methylprednisolone pulse therapy. Conversely, the second episode was not associated with significant clinical and laboratory evidence of disease activity at other sites and the initial abdominal ultrasonography was non-contributory. Diagnostic and therapeutic delays, hence, led to the development of fatal complications. We highlight that a high index of suspicion of LE and a timely aggressive treatment is imperative for optimal outcomes even in rare pediatric cases of recurrent LE that may have normal imaging findings initially and may not be associated with systemic lupus erythematosus disease activity index (SLEDAI).

Neuropsychiatric involvement in juvenile-onset systemic lupus erythematosus: Data from the UK Juvenile-onset systemic lupus erythematosus cohort study

INTRODUCTION

Juvenile-onset systemic lupus erythematosus (JSLE) is a rare autoimmune/inflammatory disease with significant morbidity and mortality. Neuropsychiatric (NP) involvement is a severe complication, encompassing a heterogeneous range of neurological and psychiatric manifestations.

METHODS

Demographic, clinical, and laboratory features of NP-SLE were assessed in participants of the UK JSLE Cohort Study, and compared to patients in the same cohort without NP manifestations.

RESULTS

A total of 428 JSLE patients were included in this study, 25% of which exhibited NP features, half of them at first visit. Most common neurological symptoms among NP-JSLE patients included headaches (78.5%), mood disorders (48.6%), cognitive impairment (42%), anxiety (23.3%), seizures (19.6%), movement disorders (17.7%), and cerebrovascular disease (14.9%). Peripheral nervous system involvement was recorded in 7% of NP-SLE patients. NP-JSLE patients more frequently exhibited thrombocytopenia (<100 × 109/L) (p = 0.04), higher C-reactive protein levels (p = 0.01), higher global pBILAG score at first visit (p < 0.001), and higher SLICC damage index score at first (p = 0.02) and last (p < 0.001) visit when compared to JSLE patients without NP involvement.

CONCLUSIONS

A significant proportion of JSLE patients experience NP involvement (25%). Juvenile-onset NP-SLE most commonly affects the CNS and is associated with increased overall disease activity and damage.

Prognostic values of procalcitonin and platelet in the patient with urosepsis

BACKGROUND

The patient suffering from urinary sepsis is often accompanied by elevated serum procalcitonin (PCT) levels and a decline in the average platelet count (PLT), which could result in a poor prognosis. This study aimed to evaluate the value of PCT and PLT in determining the severity of urinary sepsis.

METHODS

A total of 120 urosepsis patients enrolled were divided into a survival group and a death group, respectively, according to their status within 14 days after admission. Changes in PCT and PLT levels between the 2 groups were compared at different time points. A receiver operating characteristic (ROC) curve was eventually obtained to predict the prognostic value of PCT and PLT.

RESULTS

The PCT levels in the survival group declined gradually after admission, and the PLT decreased at first but increased rapidly in subsequence. The PCT level in the death group, however, declined in a flat-slope trend or was hardly noticeable together with the number of PLT reduced significantly. In particular, it is on the 3rd day that PCT tended to positively correlate with acute physiological and chronic health score II (APACHE II) score (r = 0.730, P < .05), but negatively with PLT (r = 0.472, P < .05). The APACHE II score and PLT (r = 0.612, P < .05) were also negatively correlated with each other. As indicated by the ROC curve, the PCT level on the 3rd day after admission was of great value for the clinical mortality prognosis, and the area under the curve was 0.858. Moreover, PLT also has a high predictive value for prognosis. Area under the curve is 0.951. When the PLT was more than 51 × 109 /L, the sensitivity was up to 90%, and the specificity was 90%.

CONCLUSION

PLT and PCT levels are closely related to the APACHE II score, which could indicate the severity of urosepsis in patients. The contribution of this study was to confirm that dynamic monitoring of the changes in PCT and PLT helps determine the prognosis of urosepsis patients.

Development of Prediction Models for New Integrated Models and a Bioscore System to Identify Bacterial Infections in Systemic Lupus Erythematosus

Objectives

Distinguishing flares from bacterial infections in systemic lupus erythematosus (SLE) patients remains a challenge. This study aimed to build a model, using multiple blood cells and plasma indicators, to improve the identification of bacterial infections in SLE.

Design

Building PLS-DA/OPLS-DA models and a bioscore system to distinguish bacterial infections from lupus flares in SLE.

Setting

Department of Rheumatology of the Second Hospital of Shanxi Medical University.

Participants

SLE patients with flares (n = 142) or bacterial infections (n = 106) were recruited in this retrospective study.

Outcome

The peripheral blood of these patients was collected by the experimenter to measure the levels of routine examination indicators, immune cells, and cytokines. PLS-DA/OPLS-DA models and a bioscore system were established.

Results

Both PLS-DA (R2Y = 0.953, Q2 = 0.931) and OPLS-DA (R2Y = 0.953, Q2 = 0.942) models could clearly identify bacterial infections in SLE. The white blood cell (WBC), neutrophile granulocyte (NEUT), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), IL-10, interferon-γ (IFN-γ), and tumor necrosis factor α (TNF-α) levels were significantly higher in bacteria-infected patients, while regulatory T (Treg) cells obviously decreased. A multivariate analysis using the above 10 dichotomized indicators, based on the cut-off value of their respective ROC curve, was established to screen out the independent predictors and calculate their weights to build a bioscore system, which exhibited a strong diagnosis ability (AUC = 0.842, 95% CI 0.794–0.891). The bioscore system showed that 0 and 100% of SLE patients with scores of 0 and 8–10, respectively, were infected with bacteria. The higher the score, the greater the likelihood of bacterial infections in SLE.

Conclusions

The PLS-DA/OPLS-DA models, including the above biomarkers, showed a strong predictive ability for bacterial infections in SLE. Combining WBC, NEUT, CRP, PCT, IL-6, and IFN-γ in a bioscore system may result in faster prediction of bacterial infections in SLE and may guide toward a more appropriate, timely treatment for SLE.

Aptamers for Proteins Associated with Rheumatic Diseases: Progress, Challenges, and Prospects of Diagnostic and Therapeutic Applications

Nucleic acid aptamers capable of affine and specific binding to their molecular targets have now established themselves as a very promising alternative to monoclonal antibodies for diagnostic and therapeutic applications. Although the main focus in aptamers’ research and development for biomedicine is made on cardiovascular, infectious, and malignant diseases, the use of aptamers as therapeutic or diagnostic tools in the context of rheumatic diseases is no less important. In this review, we consider the main features of aptamers that make them valuable molecular tools for rheumatologists, and summarize the studies on the selection and application of aptamers for protein biomarkers associated with rheumatic diseases. We discuss the progress in the development of aptamer-based diagnostic assays and targeted therapeutics for rheumatic disorders, future prospects in the field, and issues that have yet to be addressed.

Differential parameters between activity flare and acute infection in pediatric patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) patients are vulnerable to infections. We aim to explore the approach to differentiate active infection from disease activity in pediatric SLE patients. Fifty pediatric SLE patients presenting with 185 clinical visits were collected. The associations between both clinical and laboratory parameters and the outcome groups were analyzed using generalized estimating equations (GEEs). These 185 visits were divided into 4 outcome groups: infected-active (n = 102), infected-inactive (n = 11), noninfected-active (n = 59), and noninfected-inactive (n = 13) visits. Multivariate GEE (generalized estimating equation) analysis showed that SDI, SLEDAI-2K, neutrophil‐to‐lymphocyte ratio (NLR), hemoglobin, platelet, RDW-to-platelet ratio (RPR), and C3 are predictive of flare (combined calculated AUC of 0.8964 and with sensitivity of 82.2% and specificity of 90.9%). Multivariate GEE analysis showed that SDI, fever temperature, CRP, procalcitonin (PCT), lymphocyte percentage, NLR, hemoglobin, and renal score in SLEDAI-2k are predictive of infection (combined calculated AUC of 0.7886 and with sensitivity of 63.5% and specificity of 89.2%). We can simultaneously predict 4 different outcome with accuracy of 70.13% for infected-active group, 10% for infected-inactive group, 59.57% for noninfected-active group, and 84.62% for noninfected-inactive group, respectively. Combination of parameters from four different domains simultaneously, including inflammation (CRP, ESR, PCT), hematology (Lymphocyte percentage, NLR, PLR), complement (C3, C4), and clinical status (SLEDAI, SDI) is objective and effective to differentiate flares from infections in pediatric SLE patients.

Talaromyces marneffei Infection in Systemic Lupus Erythematosus Patients: Report of Two Cases and Review of the Literature

Purpose

Talaromyces marneffei is a highly invasive fungus, causing fatal mycosis in patients with or without HIV in Southeast and Eastern Asia. However, its presence in patients with systemic lupus erythematosus is rarely reported.

Methods

We reported two SLE patients infected by T. marneffei and reviewed other patients reported in the English literature. All cases were pooled for analysis.

Results

Eleven patients with SLE infected with T. marneffei infection were identified, including the two presented here. Three were male and eight were female; all were HIV negative. All the patients, except two where data were missing, had received immunosuppressants before T. marneffei infection. The main clinical features included fever, cough, lymph node enlargement, gastrointestinal symptoms, and rash. Five patients were misdiagnosed as having SLE exacerbation. T. marneffei was detected via culture or histopathologic analysis, with the fungus most commonly found in the blood. Seven of the 11 patients were successfully treated by timely antifungal therapy with concomitant SLE control, while four patients who did not receive antifungal therapy died.

Conclusion

T. marneffei infection should be excluded when SLE patients, especially if on long-term immunosuppressants, present with fever, cough, lymph node enlargement, gastrointestinal symptoms, and rash. Controlling the lupus and timely antifungal treatment can improve the outcomes of SLE patients with T. marneffei infection.

Clinical characteristics and prognostic risk factors of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV)

OBJECTIVE

The complement alternative pathway is involved in the development of AVV. Several studies showed that AVV patients with low serum complement C3 (sC3) levels tend to have a poor prognosis. The aim of this study was to determine whether low sC3 measured at AAV onset is a risk factor for survival prognosis in patients with AVV, and further identified other potential risk factors for predicting patient survival prognosis.

METHODS

A retrospective analysis of 52 newly onset AAV patients was performed. The clinical parameters of the AAV patients were collected. The laboratory parameters before immunosuppressive treatment were evaluated. According to the level of sC3, the patients were divided into low sC3 group (n = 19) and normal sC3 group (n = 33). Disease outcome measures included end-stage renal disease (ESRD) or death. The clinical parameters and survival rate between the two groups were compared. Spearson correlation analysis was used to analyze the correlation between sC3 and other laboratory parameters.

RESULTS

Significant differences were found regarding Birmingham Vasculitis Activity Score (BVAS), sC3, sC4, lactate dehydrogenase, blood urea nitrogen, procalcitonin (PCT), and estimated glomerular filtration rate (eGFR) between the two groups (p = 0.006, 0.000, 0.001, 0.049, 0.019, 0.000 and 0.045, respectively). The survival rate of the low sC3 group was significantly lower than that of the normal sC3 group (Log Rank Chi-square = 4.416, P = 0.036). Low sC3 was significantly associated with lower sC4 (r = 0.570, P = 0.000), lower serum albumin (r = 0.311, P = 0.025), lower eGFR (r = 0.289, P = 0.037), higher PCT (r = -0.566, P = 0.000), and higher lactate dehydrogenase (r = -0.323, P = 0.019).

CONCLUSION

This retrospective study demonstrates that AAV patients with low sC3 level at diagnosis tend to have lower baseline eGFR and poorer survival prognosis than those of the normal sC3 level. Furthermore, the high procalcitonin (PCT), low serum albumin and high lactate dehydrogenase in AVV patients may be predictors of poor prognosis.

Serum Amyloid A: A Potential Biomarker Assessing Disease Activity in Systemic Lupus Erythematosus

Background

This study aimed to investigate the association between levels of serum amyloid A (SAA) and the activity of systemic lupus erythematosus (SLE).

Material/Methods

The study included 135 patients with SLE, including 52 patients with active SLE and 83 patients with inactive SLE and 149 healthy controls. The degree of activity of SLE was assessed using the SLE Disease Activity Index 2000 (SLEDAI-2K). Serum SAA levels were measured using a Cobas 8000 c702 modular analyzer.

Results

The levels of SAA were significantly increased in patients with active SLE compared with patients with inactive SLE (median IQR, 16.65 mg/L; range, 9.35–39.68 mg/L, and median IQR, 2.30 mg/L, range, 1.30–4.80 mg/L) (p<0.001). Levels of SAA were significantly correlated with the SLEDAI-2K scores, the erythrocyte sedimentation rate (ESR), and hypersensitive C-reactive protein (Hs-CRP) in patients with SLE (r=0.726, p<0.001; r=0.631, p<0.001; r=0.774, p<0.001, respectively). Multivariate logistic regression analysis showed that the SAA values were independently associated with active SLE when controlled for white blood cell (WBC) count, red blood cell distribution width (RDW), ESR, and Hs-CRP (OR=1.772; p=0.01; 95% CI, 1.101–2.851). Receiver operating characteristic (ROC) curve analysis for SAA was used to identify patients with active SLE with an area under the curve of 0.971, a sensitivity of 90.4%, and a specificity of 94.0%.

Conclusions

SAA levels were significantly correlated with disease activity in patients with SLE.

Clinical characteristics and risk factors of infection in patients with systemic lupus erythematosus: A systematic review and meta-analysis of observational studies

OBJECTIVE

Infection is one of the major causes of morbidity and mortality in systemic lupus erythematosus (SLE) patients. We conducted a systematic review and meta-analysis to investigate the clinical characteristics and risk factors of infection in SLE by comparing demographic factors, laboratory data, clinical features, and therapeutic factors between infection and non-infection SLE patients.

METHODS

PubMed, Embase, and Cochrane databases were searched systematically without restricting the language or year (up to September 2019) by using MeSH terms and keywords pertaining to SLE and infection. Three independent reviewers selected all observational studies based on the established inclusion criteria. Odds ratio (OR) and standardized mean difference (SMD) along with 95% confidence intervals (CI) were used and the analyses were carried out by using a random/fixed-effects model. When necessary, different subgroup and sensitivity analyses were conducted. Study quality was assessed by the modified version (nine-star scoring system) of the Newcastle-Ottawa Scale (NOS) and publication bias was evaluated by funnel plots, and Egger's and Begg's tests.

RESULTS

In total, we included 39 studies (3709 infection SLE patients and 10526 non-infection SLE patients) based on the inclusion criteria. Compared with the SLE patients without infection, we found that infected SLE patients had a significantly higher incidence rate of the following: 1) lymphopenia (OR = 2.738 95%CI (1.017-7.376), P = 0.046, I² = 81.4%), 2) thrombocytopenia (OR = 1.61 95%CI (1.4-1.85), P<0.001, I² = 0%), 3) anemia (OR = 2.294 95%CI (1.402-3.755), P = 0.001, I² = 83.0%), 4) hypoproteinemia (OR = 2.336 95%CI (1.408-3.876), P = 0.001, I² = 84.2%), 5) C3 consumed (OR = 1.890 95%CI (1.190-3.002), P = 0.007, I² = 77.4%), 6) diabetes mellitus (OR = 3.890 95%CI (2.450-6.160), P < 0.001, I² = 0%), 7) elevated creatinine (OR = 1.954 95%CI (1.646-2.320), P < 0.001, I² = 0.0%), 8) renal involvement (OR = 2.692 95%CI (2.000-3.623), P < 0.001, I² = 76.0%), 9) serositis (OR = 3.877 95%CI (0.995-15.110), P = 0.051, I² = 79.1%), and 10) use of steroid immunosuppressants (OR = 3.116 95%CI (1.959-4.957), P < 0.001, I² = 77.9%). Furthermore, infected SLE patients had a significantly higher mean dose of prednisone (SMD = 2.088 95%CI (1.196-2.981), P < 0.001, I² = 97.8%). In addition, SLE patients with infection showed a significantly lower incidence of antimalarial drug use (OR = 0.634 95%CI (0.451-0.892), P = 0.009, I² = 56.0%). Infected SLE patients had a significantly higher level of 1) 24-h urinary protein (SMD = 0.560 95%CI (0.300-0.810), P < 0.001, I² = 0%), 2) CRP (SMD = 0.437 95%CI (0.184-0.691), P = 0.001, I² = 68.6%), and 3) SLE Collaborating Clinics damage index (SDI) (SMD = 0.451 95%CI (0.238-0.664), P < 0.001, I² = 0.0%), along with a significantly lower level of albumin (SMD = -0.400 95%CI (-0.610--0.200), P < 0.001, I² = 0.0%). After adjustment for false discovery rate (FDR), lymphopenia and serositis were no longer associated with the occurrence of infection; however, the remaining factors were still associated with infection in SLE. According to the nine-star scoring system of NOS, 71.79% of the studies were considered as high methodological quality (low risk of bias). No significant publication bias, except for renal involvement, was detected from funnel plots or Egger's and Begg's test, while this publication bias of renal involvement did not impact the pooled estimates.

CONCLUSION

We identified many factors including thrombocytopenia, anemia, hypoproteinemia, hypocomplementemia, hypoalbuminemia, higher level of CRP, higher SDI score, renal involvement and diabetes mellitus that were associated with infection in SLE patients. In addition, glucocorticoids (especially high-dose) and immunosuppressants (e.g. cyclophosphamide) rendered SLE patients more susceptible to infection, while antimalarial drug administration (hydroxychloroquine) was a protective factor against infection in SLE patients. SLE patients with the above clinical characteristics and risk factors might be at high risk from infection, which might contribute to the early identification of infection in SLE patients for better prognosis.

Predictive value of the neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, platelet-to-neutrophil ratio, and neutrophil-to-monocyte ratio in lupus nephritis

Objective

To evaluate the role of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-neutrophil ratio (PNR), platelet-to-monocyte ratio (PMR), and neutrophil-to-monocyte ratio (NMR) as predictors for lupus nephritis (LN) patients without infection or as biomarkers for distinguishing between infection or flare with LN patients.

Methods

LN patients were divided into three groups: LN without infection, LN with infection, and LN with flare. A total of 57 healthy subjects were enrolled as controls. The differentiation was analyzed between LN without infection and control group, and LN with infection and LN with flare. Correlations among variables were assessed in the LN group without infection. Receiver operating characteristic curves were constructed in two comparable groups.

Results

NLR, PLR, and MLR were increased significantly in the LN group without infection as compared with those in healthy controls. NLR (area under the curve (AUC): 0.75) and MLR (AUC: 0.79) were useful for distinguishing between LN patients without infection and healthy subjects. In differentiating LN patients without infection from the controls, optimal cutoffs of NLR and MLR were 3.43 (sensitivity: 45.6%, specificity: 96.5%, and overall accuracy: 68.8%) and 0.24 (sensitivity: 75.0%, specificity: 73.7%, and overall accuracy: 73.6%), respectively. In addition, NLR ( r = 0.322, p = 0.011) and PLR ( r = 0.283, p = 0.026) were positively correlated with CRP. Importantly, NLR and NMR were increased while PNR was decreased in the LN group with infection in comparison with those in the LN group with flare. NLR (AUC: 0.80), NMR (AUC: 0.78), and PNR (AUC: 0.74) were useful in differentiating LN patients with infection and flare, and their optimal cutoffs were 4.02 (sensitivity: 82.6%, specificity: 69.6%, and overall accuracy: 75.5%), 12.19 (sensitivity: 80.4%, specificity: 73.9%, and overall accuracy: 77.5%), and 28.26 (sensitivity: 65.2%, specificity: 76.8%, and overall accuracy: 71.6%), respectively.

Conclusions

We demonstrated, for the first time, that MLR or NMR had the best accuracy in differentiating LN patients without infection from healthy subjects, or differentiating infection from flare in LN patients, respectively. Our results implied that NLR, MLR, PNR, and NMR may be useful biomarkers in predicting LN.

[Fever in systemic lupus erythematosus: disease exacerbation or infection?]

The differential diagnosis of fever, especially in the context of autoimmune diseases is broad. Accordingly, the spectrum of diagnostic procedures is extensive and the therapeutic consequences are partly contradictory. Fever is basically the manifestation of an increased cell proliferation, such as classically seen in tumors, infections or autoimmune inflammation. Systemic lupus erythematosus (SLE) is one of the most multifaceted rheumatological diseases. Fever is one component of the new classification criteria which help to classify and possibly diagnose SLE. The differential work-up of fever is a special challenge for clinicians particularly in the context of the initial diagnosis of SLE or another autoimmune disease and also in the course of the disease in patients with autoimmune diseases. Based on a case report this article discusses differential diagnostic considerations and proposes a concrete differential diagnostic procedure. The patient's history is highlighted as an extremely important source of relevant information. Without claiming completeness various factors are listed, which help to differentiate fever as a consequence of SLE activity versus fever as a consequence of an infection.