Red blood cell distribution width-to-platelet ratio as a disease activity-associated factor in systemic lupus erythematosus

A Prognostic Model Incorporating Relevant Peripheral Blood Inflammation Indicator to Predict Postherpetic Neuralgia in Patients with Acute Herpes Zoster

Objective

To determine the risk of postherpetic neuralgia (PHN) in patients with acute herpes zoster (HZ), this study developed and validated a novel clinical prediction model by incorporating a relevant peripheral blood inflammation indicator.

Methods

Between January 2019 and June 2023, 209 patients with acute HZ were categorized into the PHN group (n = 62) and the non-PHN group (n = 147). Univariate and multivariate logistic regression analyses were conducted to identify risk factors serving as independent predictors of PHN development. Subsequently, a nomogram prediction model was established, and the discriminative ability and calibration were evaluated using the receiver operating characteristic curve, calibration plots, and decision curve analysis (DCA). The nomogram model was internally verified through the bootstrap test method.

Results

According to univariate logistic regression analyses, five variables, namely age, hypertension, acute phase Numeric Rating Scale (NRS-11) score, platelet-to-lymphocyte ratio (PLR), and systemic immune inflammation index, were significantly associated with PHN development. Multifactorial analysis further unveiled that age (odds ratio (OR) [95% confidence interval (CI)]: 2.309 [1.163-4.660]), acute phase NRS-11 score (OR [95% CI]: 2.837 [1.294-6.275]), and PLR (OR [95% CI]: 1.015 [1.010-1.022]) were independent risk factors for PHN. These three predictors were integrated to establish the prediction model and construct the nomogram. The area under the receiver operating characteristic curve (AUC) for predicting the PHN risk was 0.787, and the AUC of internal validation determined using the bootstrap method was 0.776. The DCA and calibration curve also indicated that the predictive performance of the nomogram model was commendable.

Conclusion

In this study, a risk prediction model was developed and validated to accurately forecast the probability of PHN after HZ, thereby demonstrating favorable discrimination, calibration, and clinical applicability.

Effects of peripheral blood cells on ischemic stroke: Greater immune response or systemic inflammation?

Ischemic stroke is still one of the most serious medical conditions endangering human health worldwide. Current research on the mechanism of ischemic stroke focuses on the primary etiology as well as the subsequent inflammatory response and immune modulation. Recent research has revealed that peripheral blood cells and their components are crucial to the ensuing progression of ischemic stroke. However, it remains unclear whether blood cell elements are principally in charge of systemic inflammation or immunological regulation, or if their participation is beneficial or harmful to the development of ischemic stroke. In this review, we aim to describe the changes in peripheral blood cells and their corresponding parameters in ischemic stroke. Specifically, we elaborate on the role of each peripheral component in the inflammatory response or immunological modulation as well as their interactions. It has been suggested that more specific therapies aimed at targeting peripheral blood cell components and their role in inflammation or immunity are more favorable to the treatment of ischemic stroke.

Platelet-to-lymphocyte ratio as a biomarker of systemic inflammation in systemic lupus erythematosus: A meta-analysis and systematic review

OBJECTIVE

The objective of this study was to evaluate the relationship between the platelet-to-lymphocyte ratio (PLR) and systemic lupus erythematosus (SLE). Additionally, the study aimed to establish an association between PLR and SLE disease activity, specifically lupus nephritis (LN).

METHODS

We conducted a comprehensive search across Medline, Embase, and Cochrane databases to identify relevant articles. Subsequently, we performed meta-analyses to compare PLR between SLE patients and controls, as well as active and inactive SLE cases, along with LN and non-LN groups. Furthermore, a meta-analysis was conducted on correlation coefficients between PLR and various parameters in SLE patients, including the SLE Disease Activity Index (SLEDAI), C3, C4, anti-dsDNA, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).

RESULTS

In total, fifteen studies comprising 1,522 SLE patients and 1,424 controls were eligible for inclusion. The meta-analysis demonstrated a significant elevation of PLR in the SLE group compared to the control group (Standardized Mean Difference [SMD] = 0.604, 95% Confidence Interval [CI] = 0.299-0.909, p < 0.001). Upon stratification by ethnicity, an elevated PLR was observed in the SLE group among both Asian and Arab populations. Subgroup analysis based on sample size revealed consistently higher PLR in both small (n < 200) and large sample (n ≥ 200) SLE groups. Moreover, when considering disease activity, there was a noteworthy trend of increased PLR in the active disease group compared to the inactive group (SMD = 0.553, 95% CI = 0.000-1.106, p = 0.050). However, the meta-analysis did not demonstrate a significant distinction in PLR between the LN and non-LN groups. Notably, a positive association was established between PLR and SLEDAI (correlation coefficient = 0.325, 95% CI = 0.176-0.459, p < 0.001). Furthermore, PLR exhibited positive correlations with ESR, CRP, proteinuria, C3, and anti-dsDNA antibody levels.

CONCLUSIONS

The outcomes of this meta-analysis underscored the elevated PLR in SLE patients, suggesting its potential as a biomarker for gauging systemic inflammation in SLE. Additionally, PLR exhibited correlations with SLEDAI, as well as with key indicators such as ESR, CRP, proteinuria, C3, and anti-dsDNA antibody levels.

Red Cell Distribution Width to Platelet Count Ratio Reference Intervals in Premature Infants Beyond the First Week of Life

Objective: Red cell distribution width (RDW) is a parameter of complete blood count (CBC). The RDW to platelet count ratio (RPR) is a new index that has been shown to reflect the severity of inflammation. We aim to determine the reference interval (RI) of RPR for premature newborns. Study design: The medical records of preterm infants who were followed up between January 2016 and December 2018 were reviewed. CBC levels were measured in 144 infants at <72 hours of age. Results: CBCs of infants (gestational age from 28 to 35weeks) had a RI of 0.038-0.126 for the RPR. The RI for RPR in infants with a gestational age of 32-35weeks was 0.042-0.129; and the RI for infants at 28-31weeks was 0.022-0.121. Conclusion: Establishment of RI for RPR in premature infants will allow clinical correlation of RPR alterations in this population.

Mean platelet volume to lymphocyte ratio and platelet distribution width to lymphocyte ratio in Iraqi patients diagnosed with systemic lupus erythematosus

Introduction

The mean platelet volume to lymphocyte ratio (MPVLR) and platelet distribution width to lymphocyte ratio (PDWLR) have the potential to serve as markers of inflammation which may indicate disease activity. The mean platelet volume to lymphocyte ratio and PDWLR were assessed in patients with systemic lupus erythematosus (SLE) in this study.

Material and methods

Sixty-two patients with systemic lupus erythematosus and 79 controls who were age and gender matched were included. Their sociodemographic information, as well as disease activity scores based on the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), disease duration, current medications, lymphocytes, platelets, platelet distribution width (PDW), and mean platelet volume (MPV), anti-nuclear antibody (ANA), anti-double stranded deoxyribonucleic acid (anti-dsDNA), and complement components (C3, C4) were recorded. The correlations of MPVLR and PDWLR with disease activity and some laboratory parameters were analyzed.

Results

Lupus patients had significantly higher median (interquartile range) values for MPVLR and PDWLR than controls (5.69 [1.16-23.67] vs. 4.40 [2.78-11.93], p = 0.009) and 10.51 (2.87-79.37) vs. 5.21 (2.88-14.66), p < 0.001] respectively. According to the ROC curve, > 7.53 was the best PDWLR cut-off value for predicting SLE with a sensitivity of 71%, a specificity of 87% and an accuracy of 82.6%, whereas the optimum MPVLR cut-off value was > 6.46 with a sensitivity of 45.2%, a specificity of 88.9% and an accuracy of 76.8%. In addition, MPVLR had a significant positive correlation with SLEDAI (r = 0.34, p = 0.008). However, there was no significant correlation between PDWLR and SLEDAI (r = 0.23, p = 0.067). Furthermore, PDWLR had a significant positive correlation with PDW (r = 0.482, p < 0.001), while MPVLR had a significant negative correlation with C3 level (r = -0.260, p = 0.042). Both PDWLR and MPVLR were positively correlated with nephritis (r = 0.388, p = 0.002; r = 0.246, p = 0.038, respectively).

Conclusions

The platelet distribution width to lymphocyte ratio can be considered as an assisting biomarker in the diagnosis of SLE with the other clinical and serological parameters. The mean platelet volume to lymphocyte ratio may be used in the evaluation of disease activity in SLE patients.

Evaluation of red blood cell distribution width-platelet ratio as a predictor of adverse pregnancy outcomes and disease severity in systemic lupus erythematosus

OBJECTIVE

The red blood cell distribution width to platelet ratio (RPR) is known to reflect systemic inflammation. This study aimed to explore the predictive value of RPR for disease activity and adverse pregnancy outcomes (APOs) in pregnant women with systemic lupus erythematosus (SLE).

METHODS

We retrospectively evaluated case data of all pregnant women with SLE managed at the First Affiliated Hospital of Zhengzhou University from January 2014 to March 2017. Correlations between RPR and SLE clinical disease activity, organ involvement, and maternal complications were analysed. Changes in the RPR and erythrocyte sedimentation rate (ESR) were observed before and after treatment. A receiver operating characteristic (ROC) curve was used to predict disease activity and APOs based on RPR.

RESULTS

A total of 118 patients were enrolled, including 77 in the disease-active group and 41 in the disease-inactive group. The live birth rate was significantly higher in the disease-inactive group than in the disease-active group (P < 0.001). Compared to the disease-inactive group, the number of patients with elevated RPR, anti-dsDNA antibody level, and ESR was significantly higher in the disease-active group, whereas their platelet-lymphocyte ratios and complement 3 and 4 levels were significantly lower. The disease-active group was more likely to experience APOs (P < 0.001), mainly due to premature birth, low birth weight, and pregnancy loss. The ROC curve indicated that RPR had an effect on disease activity and APOs.

CONCLUSION

RPR can be used as a predictor of disease severity and APOs in pregnant women with SLE. Key Points • RPR positively correlated with SLEDAI; patients with elevated RPR have higher disease activity, more organ, and more maternal complications. • Monitoring RPR could better predict disease activity in pregnant patients with SLE and reduce the incidence of maternal complications and APOs.

Red Cell Distribution Width and Mean Platelet Volume in Patients With Ankylosing Spondylitis: A Systematic Review and Meta-analysis

OBJECTIVE

The results of previous studies regarding the relationship between red cell distribution width (RDW) or mean platelet volume (MPV) levels and ankylosing spondylitis (AS) are inconsistent. Therefore, we conducted this meta-analysis to systematically evaluate the associations.

METHODS

The Web of Science, PubMed, and Cochrane Library (as of February 14, 2019) were used to retrieve relevant articles. Pooled standard mean difference (SMD) and its 95% confidence interval (CI) were calculated. All statistical analyses were performed using the "meta" and "metafor" packages of the R 3.5.1 software.

RESULTS

Nine studies on RDW, including 775 AS patients and 972 healthy controls, and 8 studies on MPV, including 743 AS patients and 571 healthy controls, were included. The results showed that RDW levels were significantly higher in AS patients (SMD = 0.67; 95% CI, 0.30 to 1.05; p < 0.001) compared with healthy controls, whereas MPV levels (SMD = 0.01; 95% CI, -0.28 to 0.30; p = 0.929) were not significantly different from healthy controls.

CONCLUSIONS

Our current study shows that the elevated levels of RDW may be associated with AS, whereas MPV levels may be not associated with AS.

Red Cell Distribution Width to Platelet Count Ratio: A Promising Routinely Available Indicator of Mortality for Acute Traumatic Brain Injury

Prognosis evaluation is crucial for the effective management of patients with acute traumatic brain injury (TBI). However, there is still a lack of routinely available blood indicators for mortality risk in clinical practice. To investigate whether blood red cell distribution width to platelet count ratio (RPR) correlates with hospital mortality of TBI, clinical data of 2220 patients with TBI were extracted from two large intensive care unit cohorts (MIMIC-III and eICU Database), and were integratively analyzed using our developed method named MeDICS. We found that higher RPR can be observed among non-survivors than survivors of TBI (p < 0.001). It had a moderately good prognostic performance for mortality with an area under receiver-operating characteristic curve (AUC) of 0.7367, which was greater than that of Glasgow Coma Scale (GCS; AUC = 0.6022). Besides, the nomogram consisting of RPR, GCS, and other risk factors was developed, where 10-fold cross-validation was performed to protect it against overfitting. A Harrell's C-index of 0.8523 was determined, suggesting an improved prognostic value based on RPR. The in vivo experiments further confirmed the association between RPR and neuro-outcome after TBI. It indicated that the continuous change in RPR post-injury is attributed to the development of inflammation, which emphasized the importance of controlling inflammatory response in clinical treatment. Taken together, RPR is a promising routinely available predictor of mortality for acute TBI. The nomogram generated from it can be used in resource-limited settings, thus be proposed as a prognosis evaluation aid for patients with TBI in all levels of medical system.

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.

An Evaluation of the Different Serum Markers Associated with Mortality in Crimean-Congo Hemorrhagic Fever

BACKGROUND

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease with a high mortality rate. Although CCHF has been widely investigated over the past decade, a review of the literature indicated no data on the prognostic capacity of the mean platelet volume-to-platelet count ratio (MPVPCR) and the red cell distribution width-to-platelet count ratio (RDWPCR) for the systemic inflammatory response in patients with CCHF. This study aimed to evaluate the prognostic ability of MPVPCR and RDWPCR on mortality in patients with CCHF.

METHODS

A total of 807 patients that were admitted to the Cumhuriyet University Hospital's Emergency Department from January 2010 to December 2018 were involved. The RDWPCR and MPVPCR were separately calculated via absolute blood red cell and platelet counts at the time of admission. Before performing receiver-operating characteristic (ROC) curve analysis to define the optimum cut-off values of MPVPCR and RDWPCR stepwise logistic regression analysis was used to determine the predictive factors related to mortality in CCHF patients.

RESULTS

Values of both MPVPCR and RDWPCR were significantly lower in survivors than in non-survivors (MPVPCR: 0.20±0.23 versus 0.55±0.55, P<0.001; RDWPCR: 0.27±0.32 versus 0.77±0.77, P<0.001, respectively). The MPVPCR (odds ratio [OR], 5.95; P=0.048) was an independent predictor for the prognosis of mortality in CCHF patients. The area under the curve in the ROC curve analysis for MPVPCR was 0.876 with a cut-off of 0.21 (sensitivity 87%, specificity 76%).

CONCLUSION

At the time of admission, MPVPCR might be a useful predictor of mortality in patients with CCHF.

Red Cell Distribution Width as a Predictor of Malignancy in Patients Who Underwent Upper Gastrointestinal System Endoscopy

Introduction

Red cell distribution width (RDW) has predictive properties in different benign and malignant diseases.

Aim

Our aim was to evaluate the predictive value of RDW for malignant gastric lesions by upper gastrointestinal screening.

Materials and Methods

Data of 91 male patients (Group A) who underwent upper gastrointestinal endoscopy and subsequent surgery for gastric malignancy and age-matched 91 healthy male patients (Group B) with benign disorders were reviewed in this retrospective cohort study. The pathology reports, laboratory parameters, and demographics of the patients were recorded for comparison. Receiver operating characteristic curves were plotted for RDW, and a threshold for prediction of malignancy was calculated.

Results

The average age of the patients with gastric cancer was 62 (interquartile range [IQR]: 53-70) years. The difference in RDW levels between Group A and Group B was found to be significant: 14.40% (IQR: 13.40-16.40) versus 13.10% (IQR: 12.55-13.50) for the malignant and benign groups, respectively, P = 0.000. The area under the curve was 0.81 (95% confidence interval [CI]: 0.76-0.86), P = 0.000. For the threshold of 13.45%, the positive predictive value (PPV) for malignancy was found to be 69.15 (95% CI: 61.77-75.67) and negative predictive value (NPV) was 70.45 (95% CI: 62.60-77.26).

Conclusion

RDW was found to have a PPV for malignancy in nearly two-thirds of the patients and had a similar NPV.

Mean Platelet Volume-to-Platelet Count Ratio, Mean Platelet Volume-to-Lymphocyte Ratio, and Red Blood Cell Distribution Width-Platelet Count Ratio as Markers of Inflammation in Patients with Ascending Thoracic Aortic Aneurysm

OBJECTIVE

Ascending thoracic aortic aneurysm (ATAA), seen in adults, is an important cause of morbidity and mortality. In this study, we aimed to evaluate the levels of mean platelet volume (MPV), mean platelet volume-to-platelet count ratio (MPVPCR), mean platelet volume-to-lymphocyte ratio (MPVLR), and red cell distribution width platelet count ratio (RDWPCR) in patients with thoracic aortic aneurysm.

METHODS

105 patients admitted to the emergency department were diagnosed with thoracic aortic aneurysm between January and December 2014, and 100 healthy individuals were involved in this retrospective study. MPV, MPVLR, MPVPCR and RDWPCRs were calculated at the time of admission.

RESULTS

Platelet and lymphocyte levels were found to be significantly lower in the patient group when compared to the healthy group (P<0.001, P<0.001, respectively), while MPV, MPVPCR, MPVLR and RDWPCR were found to be significantly higher (P<0.001, P<0.001, P<0.001, and P=0.013, respectively). In the patient group, the high-sensitivity C-reactive protein was significantly higher (P<0.001), and the neutrophil (P=0.062) was also higher. In ROC analysis, MPVPCR had the highest sensitivity (80%) and RDWPCR had the highest specificity (72%).

CONCLUSION

The results for MPV, MPVPCR, MPVLR and RDWPCR can be evaluated as useful parameters in the emergency clinical approach in the evaluation of inflammatory activity in ATAA patients. More extensive studies are required to address the role of these parameters in determining the severity of the disease.

Neutrophil to lymphocyte ratio and platelet to lymphocyte ratio in patients with systemic lupus erythematosus and their correlation with activity: A meta-analysis

OBJECTIVE

The neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) have been suggested to be potential biomarkers for systemic lupus erythematosus (SLE). We thus performed this meta-analysis to investigate the relationship between NLR and PLR and SLE.

METHODS

A literature review was conducted by searching the Pubmed, Embase, Cochrane and Wanfang online databases from inception to 1 June 2019. Studies were pooled and the standard mean difference (SMD) with 95% confidence interval (CI) was calculated using a random-effect or fixed-effect model.

RESULTS

A total of fourteen studies were eventually included in the meta-analysis, of which nine (1246 SLE patients and 976 healthy controls) reported the NLR of SLE patients and healthy controls, six (646 SLE patients, 524 healthy controls) reported the PLR of SLE patients and healthy controls, nine (1128 SLE patients) reported the correlation coefficients between the NLR and SLE disease activity index (SLEDAI) in SLE patients, and six (715 SLE patients) reported correlation coefficients between PLR and SLEDAI in SLE patients. The NLR and PLR in SLE patients were significantly higher than in healthy controls (SMD = 1.004, 95%CI = 0.781-1.227, P < 0.001, SMD = 0.709, 95%CI = 0.58-0.838, P < 0.001), and were both positively correlated with SLEDAI (correlation coefficient = 0.429, 95%CI = 0.288-0.552, P < 0.001, correlation coefficient = 0.309, 95%CI = 0.091-0.498, P < 0.001, respectively).

CONCLUSION

NLR and PLR were significantly higher in SLE patients compared with healthy controls, and were positively correlated with SLEDAI, suggesting that NLR and PLR are useful biomarkers in the management of SLE.

Red cell distribution width to platelet ratio for liver fibrosis: a systematic review and meta-analysis of diagnostic accuracy

Introduction: Red cell distribution width to platelet ratio (RPR) may be a useful marker for the evaluation of liver fibrosis in chronic liver disease (CLD). We sought to investigate its value in fibrosis-related outcomes in a meta-analysis of diagnostic accuracy. Areas covered: We searched MEDLINE (1966-2019), Clinicaltrials.gov (2008-2019), Cochrane Central Register of Controlled Trials (CENTRAL) (1999-2019), Google Scholar (2004-2019) and WHO (International Clinical Trials Register Platform) databases using a structured algorithm. The articles were assessed by Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2). In over 1,800 patients for each outcome, pooled sensitivity and specificity for a) significant fibrosis, b) advanced fibrosis and c) cirrhosis were: a) 0.635 and 0.769 with an AUC of 0.747, b) 0.607 and 0.783 with an AUC of 0.773, c) 0.739 and 0.768 with an AUC of 0.818 respectively. Similar results were found for chronic hepatitis B in all outcomes. Subgroup analysis indicated a high specificity for advanced fibrosis detection in primary biliary cirrhosis. Sensitivity analysis did not alter the results. Expert opinion: RPR is a good predictor of fibrosis, especially as severity of chronic liver disease progresses. Future research should elucidate its value in specific etiologies of chronic liver disease.

Are There Any Relationships Between Abnormal Seminal Parameters and Neutrophil-Lymphocyte Ratio, Platelet-Lymphocyte Ratio, and Red Blood Cell Distribution-Platelet Ratio?

Objective The aim of this study is to determine the relationship between neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and red blood cell distribution width (RDW)/platelet ratio (RPR) values, which are pro-inflammatory markers, with abnormal sperm parameters, and to evaluate their availability as predictive markers. Materials and methods A total of 160 patients, 80 of whom were the control group, formed with match-pair analysis (Group 1), and 80 patients with abnormal sperm analysis, who met the study criteria (Group 2), were included in the study. Complete blood count results were recorded. NLR, PLR, and RPR values were calculated using hematological parameters, and a comparison was made between the two groups. Results The mean age was 31.23 ± 5.1 years in Group 1 and 31.33 ± 6.4 years in Group 2. NLR values were 1.84 ± 0.57-1.87 ± 0.65 (P =0.77), PLR values were 105.42 ± 23.89-111.42 ± 34.54 (P = 0.62) and RPR values were 0.05 ± 0.009-0.05 ± 0.01 (P =0.45), respectively. There was no statistically significant difference between the groups. Conclusions We investigated whether NLR, PLR, and RPR results can be used as a predictive marker on abnormal sperm parameters. We do not recommend the use of these parameters as a predictive marker.

The Platelet-to-Lymphocyte Ratio as an Inflammatory Marker in Rheumatic Diseases

The platelet-to-lymphocyte ratio (PLR) has emerged as an informative marker revealing shifts in platelet and lymphocyte counts due to acute inflammatory and prothrombotic states. PLR has been extensively examined in neoplastic diseases accompanied by immune suppression and thrombosis, which can be predicted by combined blood cell counts and their ratios. Several large observational studies have demonstrated the value of shifts in PLR in evaluating the severity of systemic inflammation and predicting infections and other comorbidities, in inflammatory rheumatic diseases. The value of PLR as an inflammatory marker increases when its fluctuations are interpreted along with other complementary hematologic indices, particularly the neutrophil-to-lymphocyte ratio (NLR), which provides additional information about the disease activity, presence of neutrophilic inflammation, infectious complications, and severe organ damage in systemic lupus erythematosus. PLR and NLR have high predictive value in rheumatic diseases with predominantly neutrophilic inflammation (e.g., Behçet disease and familial Mediterranean fever). High PLR, along with elevated platelet count, is potentially useful in diagnosing some systemic vasculitides, particularly giant-cell arteritis. A few longitudinal studies on rheumatic diseases have demonstrated a decrease in PLR in response to anti-inflammatory therapies. The main limitations of PLR studies are preanalytical faults, inadequate standardization of laboratory measurements, and inappropriate subject selection. Nonetheless, accumulating evidence suggests that PLR can provide valuable information to clinicians who encounter multisystem manifestations of rheumatic diseases, which are reflected in shifts in platelet, lymphocyte, neutrophil, or monocyte counts. Interpretation of PLR combined with complementary hematologic indices is advisable to more accurately diagnose inflammatory rheumatic diseases and predict related comorbidities.