Effects of interleukin-1 and tumor necrosis factor on megakaryocytopoiesis: mechanism of reactive thrombocytosis

Limited value of platelet-related markers in diagnosing periprosthetic joint infection

OBJECTIVE

To evaluate the diagnostic values of serum platelet count (PC), mean platelet volume ratio (MPV), platelet count to mean platelet volume ratio (PVR), platelet to lymphocyte ratio (PLR), platelet to neutrophil ratio (PNR), PC/Albumin-globulin ratio (PC/AGR), and PC/C-reactive protein (PC/ CRP) in the diagnosis of periprosthetic joint infection (PJI).

METHODS

The medical records were retrospectively analyzed of the 158 patients who had undergone hip or knee revisions from January 2018 to May 2022. Of them, 79 cases were diagnosed with PJI and 79 with aseptic loosening (AL). PJI was defined using the Musculoskeletal Infection Society criteria. The plasma levels of CRP, the erythrocyte sedimentation rate (ESR), PC, MPV, PVR, PLR, PNR, PC/AGR, and PC/CRP in the 2 groups were recorded and analyzed. In addition, tests were performed according to different joint types. The receiver operating characteristic curve was used to calculate the sensitivity and specificity of each indicator. The diagnostic value for each indicator was calculated according to the area under the curve (AUC).

RESULTS

The PC, PVR, PLR and PC/AGR levels in the PJI group were significantly higher than those in the AL group, while PC/CRP levels were significantly lower (P < 0.001). The AUC for PC/CRP, and PC/AGR was 0.804 and 0.802, respectively, which were slightly lower than that of CRP (0.826) and ESR (0.846). ROC analysis for PC/CRP, and PC/AGR revealed a cut-off value of 37.80 and 160.63, respectively, which provided a sensitivity of 73.42% and 84.81% and a specificity of 75.95% and 65.82% for PJI. The area under the curve of PLR and PC was 0.738 and 0.702. The area under the curve values for PVR, PNR, and MPV were 0.672, 0.553, and 0.544, respectively.

CONCLUSIONS

The results of this study suggest that PC, PLR, PC/CRP, and PC/AGR values do not offer significant advantages over ESR or CRP values when employed for the diagnosis of PJI. PVR, PNR, and MPV were not reliable in the diagnosis of PJI.

Assistive diagnostic indicators for infections related to lumbar posterior interbody fusion internal fixation: platelet count and mean platelet volume

BACKGROUND

The most severe complication after posterior single-segment lumbar interbody fusion and internal fixation (PIFIF) surgery for degenerative lumbar diseases is deep surgical site infection (DSSI). Preoperatively diagnosing such complications proves to be challenging. Platelets, as acute-phase reactants, undergo changes in response to infections and inflammation. This study aims to assess whether platelet indices can further aid in the diagnosis of DSSI.

METHODS

A single-center retrospective study was conducted from January 2016 to February 2021 at Xi'an Jiaotong University-Affiliated Honghui Hospital, involving 83 patients who underwent revision surgery after PIFIF due to lumbar degenerative diseases. Among them, 24 patients were diagnosed with DSSI based on combined bacterial culture and imaging data. Preoperative complete serological indicators including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and platelet count and mean platelet volume ratio (P/M ratio) were analyzed using receiver operating characteristic (ROC) curve analysis to determine cutoff values, sensitivity, and specificity. This was done to further assess the ability of these serological indicators to identify the occurrence of DSSI after PIFIF.

RESULTS

There were no significant differences in baseline demographic characteristics between the two patient groups (P > 0.05). The P/M ratio was 13.54 ± 5.05 in the aseptic revision group, while it was 19.21 ± 6.30 in the DSSI revision patients, showing a significant difference (P < 0.001). ROC curve analysis revealed that the optimal cutoff value for the P/M ratio was 17.50, with a sensitivity of 58.3% and a specificity of 78.6%. The areas under the curve (AUC) for ESR, CRP, and P/M ratio were 0.797, 0.845, and 0.756, respectively. The negative predictive value (NPV) was 87.04%, 89.47%, and 82.45%, respectively; the positive predictive value (PPV) was 58.62%, 69.23%, and 53.84%, respectively, for ESR, CRP, and P/M ratio, respectively. When P/M ratio is used in combination with ESR and CRP, the AUC is 0.887, with a sensitivity of 95.4%, specificity of 67.8%, NPV of 97.56%, PPV of 54.76%. The diagnostic performance of the model for evaluating DSSI is significantly improved compared to using ESR and CRP alone (P < 0.05).

CONCLUSION

Platelets and their related serum biomarkers are closely associated with DSSI. The P/M ratio can serve as a reliable test for screening DSSI and is worth considering for inclusion in the assessment of patients at risk of developing DSSI after potential PIFIF surgery.

Sustained effect of leukocytapheresis/granulocytapheresis versus anti-human TNF-α monoclonal antibody on ulcerative colitis: A 2-year retrospective study

Although anti-tumor necrosis factor-α monoclonal antibody biological preparations (BP) agents are widely used as an established treatment tool for refractory ulcerative colitis (UC), whether leukocytapheresis/granulocytapheresis (L/G-CAP) has similar beneficial impact on the disease activity remains undetermined. Furthermore, the costs defrayed for the treatment with these 2 modalities have not been compared. We retrospectively evaluated whether L/G-CAP offered sustained beneficial effects over 2-year period. The patients who had moderately to severely active UC (Rachmilewitz clinical activity index (CAI) ≧ 5) and were treated with a series (10 sessions) of L/G-CAP (n = 19) or BP (n = 7) as an add-on therapy to conventional medications were followed. Furthermore, the cost-effectiveness pertaining to the treatment with L/G-CAP and BP was assessed over 12 months. At baseline, L/G-CAP and BP groups manifested similar disease activity (CAI, L/G-CAP; 7.0 [6.0-10.0], BP; 10.0 [6.0-10.0], P = .207). The L/G-CAP and BP treatment suppressed the activity, with CAI 1 or less attained on day 180. When the L/G-CAP group was dichotomized into L/G-CAP-high and L/G-CAP-low group based on CAI values (≥3 or < 3) on day 365, CAI was gradually elevated in L/G-CAP-high group but remained suppressed in L/G-CAP-low group without additional apheresis for 2 years. Anemia was corrected more rapidly and hemoglobin levels were higher in BP group. The cost of the treatment with L/G-CAP over 12 months was curtailed to 76% of that with BP (1.79 [1.73-1.92] vs 2.35 [2.29-3.19] million yen, P = .028). L/G-CAP is as effective as BP in a substantial number of patients over 2 years. The cost for the treatment of UC favors L/G-CAP although the correction of anemia may prefer BP. Thus, L/G-CAP can effectively manage the disease activity with no additional implementation for 2 years although further therapeutic modalities might be required in a certain population with high CAI observed on day 365.

Elevated platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio in patients with polymyositis/dermatomyositis: a retrospective study

OBJECTIVES

This study aimed to examine the diagnostic and prognostic value of the platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) in patients with polymyositis/dermatomyositis (PM/DM).

METHOD

Clinical data of 200 patients with PM/DM and 204 healthy controls were retrospectively reviewed. We examined whether the PLR and NLR were associated with PM/DM.

RESULTS

The PLR and NLR were higher in patients with PM/DM than in controls (both P < 0.001). The PLR and NLR were higher in patients with DM than in those with PM (both P < 0.01). The PLR was higher in the anti-melanoma differentiation-associated protein-5 (anti-MDA5) ⁺ PM/DM group than in the anti-MDA5^- PM/DM group (P = 0.002). The NLR in non-survivors was higher than that in survivors (P = 0.01). The NLR was positively correlated with the occurrence of interstitial lung disease (ILD). The PLR and NLR were independent predictors of PM/DM, as well as risk factors (both P < 0.001). Moreover, the NLR had a predictive value for PM/DM-ILD and was closely related to mortality (P = 0.033, P = 0.003, respectively).

CONCLUSIONS

Patients with PM/DM have a higher NLR and PLR than healthy controls, especially in those with anti-MDA5⁺. The PLR and NLR are independent risk factors for PM/DM and have some predictive value. The NLR is correlated with ILD and associated with an increased risk of mortality in patients with PM/DM. The NLR and PLR may be simple, economical, and accurate diagnostic and prognostic markers for patients with PM/DM. Key points • The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been studied in numerous inflammatory diseases as potential markers, but their clinical significance in polymyositis/dermatomyositis (PM/DM) remains unclear. • We examined the changes in the NLR and PLR between patients with PM/DM and healthy controls, as well as their association with mortality, interstitial lung disease, and anti-melanoma differentiation-associated protein-5. • Patients with PM/DM may benefit from using the NLR and PLR as simple, economical, and accurate diagnostic and prognostic markers.

Toll-like Receptors and Thrombopoiesis

Platelets are the second most abundant blood component after red blood cells and can participate in a variety of physiological and pathological functions. Beyond its traditional role in hemostasis and thrombosis, it also plays an indispensable role in inflammatory diseases. However, thrombocytopenia is a common hematologic problem in the clinic, and it presents a proportional relationship with the fatality of many diseases. Therefore, the prevention and treatment of thrombocytopenia is of great importance. The expression of Toll-like receptors (TLRs) is one of the most relevant characteristics of thrombopoiesis and the platelet inflammatory function. We know that the TLR family is found on the surface or inside almost all cells, where they perform many immune functions. Of those, TLR2 and TLR4 are the main stress-inducing members and play an integral role in inflammatory diseases and platelet production and function. Therefore, the aim of this review is to present and discuss the relationship between platelets, inflammation and the TLR family and extend recent research on the influence of the TLR2 and TLR4 pathways and the regulation of platelet production and function. Reviewing the interaction between TLRs and platelets in inflammation may be a research direction or program for the treatment of thrombocytopenia-related and inflammatory-related diseases.

Platelet Versus Megakaryocyte: Who Is the Real Bandleader of Thromboinflammation in Sepsis?

Platelets are mainly known for their key role in hemostasis and thrombosis. However, studies over the last two decades have shown their strong implication in mechanisms associated with inflammation, thrombosis, and the immune system in various neoplastic, inflammatory, autoimmune, and infectious diseases. During sepsis, platelets amplify the recruitment and activation of innate immune cells at the site of infection and contribute to the elimination of pathogens. In certain conditions, these mechanisms can lead to thromboinflammation resulting in severe organ dysfunction. Here, we discuss the interactions of platelets with leukocytes, neutrophil extracellular traps (NETs), and endothelial cells during sepsis. The intrinsic properties of platelets that generate an inflammatory signal through the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome are discussed. As an example of immunothrombosis, the implication of platelets in vaccine-induced immune thrombotic thrombocytopenia is documented. Finally, we discuss the role of megakaryocytes (MKs) in thromboinflammation and their adaptive responses.

Interleukin-10 in the Vasculature: Pathophysiological Implications

Interleukin-10 (IL-10) is an important immunomodulatory cytokine, initially characterized as an anti-inflammatory agent released by immune cells during infectious and inflammatory processes. IL-10 exhibits biological functions that extend to the regulation of different intracellular signaling pathways directly associated with vascular function. This cytokine plays a vital role in vascular tone regulation through the change of important proteins involved in vasoconstriction and vasodilation. Numerous investigations covered here have shown that therapeutic strategies inducing IL-10 result in anti-inflammatory, anti-hypertrophic, antihyperplastic, anti-apoptotic and antihypertensive effects. This non-systematic review summarizes the modulating effects mediated by IL-10 in vascular tissue, particularly on vascular tone, and the intracellular pathway induced by this cytokine. We also highlight the advances in IL-10 manipulation as a therapeutic target in different cardiovascular pathophysiologies, including the physiological implications in animals and humans. Finally, the review illustrates current and potential future perspectives of the potential use of IL-10 in clinical trials, based on the clinical evidence.

The effect of inflammatory factors and their inhibitors on the hematopoietic stem cells fate

Inflammatory cytokines exert different effects on hematopoietic stem cells (HSCs), lead to the development of various cell lineages in bone marrow (BM) and are thus a differentiation axis for HSCs. The content used in this article has been obtained by searching PubMed database and Google Scholar search engine of English-language articles (1995-2020) using "Hematopoietic stem cell," "Inflammatory cytokine," "Homeostasis," and "Myelopoiesis." Inflammatory cytokines are involved in the differentiation and proliferation of hematopoietic progenitors to compensate for cellular death due to inflammation. Since each of these cytokines differentiates HSCs into a specific cell line, the difference in the effect of these cytokines on the fate of HSC progenitors can be predicted. Inhibitors of these cytokines can also control the inflammatory process as well as the cells involved in leukemic conditions. In general, inflammatory signaling can specify the dominant cell line in BM to counteract inflammation and leukemic condition via stimulating or inhibiting hematopoietic progenitors. Therefore, detection of the effects of inflammatory cytokines on the differentiation of HSCs can be an appropriate approach to check inflammatory and leukemic conditions and the suppression of these cytokines by their inhibitors allows for control of homeostasis in stressful conditions.

Diagnostic Utility of Platelet Count/Lymphocyte Count Ratio and Platelet Count/Mean Platelet Volume Ratio in Periprosthetic Joint Infection Following Total Knee Arthroplasty

BACKGROUND

Diagnosing a periprosthetic joint infection (PJI) can be challenging and often requires a combination of clinical and laboratory findings. Monocyte/lymphocyte ratio, neutrophil/lymphocyte ratio, platelet/lymphocyte ratio (PLR), and platelet/mean platelet volume ratio (PVR) are simple predictors for inflammation that can be readily obtained from complete blood count. The aim of this study is to evaluate the diagnostic utility of these markers in predicting PJI in total knee arthroplasty (TKA) patients.

METHODS

A total of 538 patients who underwent revision TKA with calculable marker ratios prerevision in 2 groups were evaluated: (1) 206 patients with a preoperative diagnosis of PJI (group I) and (2) 332 patients treated for revision TKA for aseptic failures (group II). The diagnostic abilities of the markers were assessed via receiver operator characteristic curve analysis.

RESULTS

The optimal threshold of PVR at 30.82 had the highest sensitivity of 87.7%, while the optimal threshold of PLR at 234.13 had the highest specificity of 82.5%. Both PLR and PVR, when combined with Musculoskeletal Infection Society thresholds for erythrocyte sedimentation rate, C-reactive protein, synovial WBC, and PMN%, achieve significantly higher sensitivity and specificity rates for PJI at or above 97% (PLR: 99.03%; 98.80%; PVR: 98.54%;97.89%).

CONCLUSION

Our study demonstrates that PVR and PLR, which are readily available and inexpensive to obtain from complete blood counts, when combined with serum and synovial fluid markers have increased sensitivity and specificity comparable to that of alpha defensin. This suggests that PVR and PLR can be used together with other hematologic and aspirate markers to increase the accuracy of PJI diagnosis in TKA patients.

Evaluation of platelet count, erythrocyte sedimentation rate and C-reactive protein levels in paediatric patients with inflammatory and infectious disease

Inflammatory and infectious diseases are the major causes of morbidity and mortality. The identification of markers for the assessment of disease activity and response to treatment can improve long-term prognosis. The aim of this study was to evaluate platelet count, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) among children with inflammatory and infectious disease. This cross-sectional study was conducted in the paediatric immunology and infectious units of Shahid Madani Hospital of Khorramabad. One hundred fifty children, half boys and half girls, with diagnoses of infectious and inflammatory diseases were included in the study. Platelet count, ESR and CRP were measured at the time of hospitalization and thereafter (recovery phase). A questionnaire including demographic information, diagnosis and paraclinical data was completed. At the time of hospitalization, all 150 children had abnormal ESR, 110 (73.3%) had abnormal CRP and 12 (92%) had alterations in platelet count. At the time of discharge, one patient (0.7%) had normal ESR, 132 (88%) had normal CRP and 140 patients (93.3%) had normal platelet count. At the time of discharge, we found a significant difference between the levels of CRP and platelets in girls. This study showed that CRP level is useful during treatment follow-up. Changes in platelet count are likely to be more prevalent in girls.

A Novel Adjunct Indicator of Periprosthetic Joint Infection: Platelet Count and Mean Platelet Volume

BACKGROUND

Diagnosing a periprosthetic joint infection (PJI) is difficult and often requires a combination of objective findings. The purpose of this study is to determine whether platelets, a known acute phase reactant, would be able to further aid in the diagnosis of PJI.

METHODS

A single-institution retrospective review study was performed on all revision total hip and knee arthroplasties done between 2000 and 2016 (n = 4939). PJI was defined by Musculoskeletal Infection Society criteria (n = 949). Platelet count and mean platelet volume were assessed from each patient's preoperative complete blood count. These values were then assessed as a ratio via receiver operating characteristic (ROC) curve analysis.

RESULTS

The platelet count to mean platelet volume ratio for PJI patients was 33.45 compared to 25.68 for patients in the aseptic revision cohort (P < .001). ROC curve analysis demonstrates that a ratio of 31.70 has a sensitivity of 48.10 (95% confidence interval 44.9-51.4) and a specificity of 80.85 (95% confidence interval 79.6-82.1). This specificity was higher than that of both estimated sedimentation ratio (ESR) and C-reactive protein (CRP) for the same cohorts using optimal values determined via ROC curve analysis. When used in conjunction with ESR and CRP, there was a statistically significant increase in the diagnostic performance of the model used to assess PJI relative to the model that just employed ESR and CRP (P < .05).

CONCLUSION

Our study demonstrates that platelets and their associated serum biomarkers are associated with PJI and warrant consideration in patients who are being evaluated for potential PJI.

Dual role of IL-21 in megakaryopoiesis and platelet homeostasis

Gene profiling studies have indicated that in vitro differentiated human megakaryocytes express the receptor for IL-21 (IL-21R), an immunostimulatory cytokine associated with inflammatory disorders and currently under evaluation in cancer therapy. The aim of this study was to investigate whether IL-21 modulates megakaryopoiesis. We first checked the expression of IL-21 receptor on human bone marrow and in vitro differentiated megakaryocytes. We then investigated the effect of IL-21 on the in vitro differentiation of human blood CD34⁺ progenitors into megakaryocytes. Finally, we analyzed the consequences of hydrodynamic transfection-mediated transient expression of IL-21, on megakaryopoiesis and thrombopoiesis in mice. The IL-21Rα chain was expressed in human bone marrow megakaryocytes and was progressively induced during in vitro differentiation of human peripheral CD34⁺ progenitors, while the signal transducing γ chain was down-regulated. Consistently, the STAT3 phosphorylation induced by IL-21 diminished during the later stages of megakaryocytic differentiation. In vitro, IL-21 increased the number of colony-forming unit megakaryocytes generated from CD34⁺ cells and the number of megakaryocytes differentiated from CD34⁺ progenitors in a JAK3- and STAT3-dependent manner. Forced expression of IL-21 in mice increased the density of bi-potent megakaryocyte progenitors and bone marrow megakaryocytes, and the platelet generation, but increased platelet clearance with a consequent reduction in blood cell counts. Our work suggests that IL-21 regulates megakaryocyte development and platelet homeostasis. Thus, IL-21 may link immune responses to physiological or pathological platelet-dependent processes.

Pre-treatment whole blood gene expression is associated with 14-week response assessed by dynamic contrast enhanced magnetic resonance imaging in infliximab-treated rheumatoid arthritis patients

Approximately 30% of rheumatoid arthritis patients achieve inadequate response to anti-TNF biologics. Attempts to identify molecular biomarkers predicting response have met with mixed success. This may be attributable, in part, to the variable and subjective disease assessment endpoints with large placebo effects typically used to classify patient response. Sixty-one patients with active RA despite methotrexate treatment, and with MRI-documented synovitis, were randomized to receive infliximab or placebo. Blood was collected at baseline and genome-wide transcription in whole blood was measured using microarrays. The primary endpoint in this study was determined by measuring the transfer rate constant (K_trans) of a gadolinium-based contrast agent from plasma to synovium using MRI. Secondary endpoints included repeated clinical assessments with DAS28(CRP), and assessments of osteitis and synovitis by the RAMRIS method. Infliximab showed greater decrease from baseline in DCE-MRI K_trans of wrist and MCP at all visits compared with placebo (P<0.001). Statistical analysis was performed to identify genes associated with treatment-specific 14-week change in K_trans. The 256 genes identified were used to derive a gene signature score by averaging their log expression within each patient. The resulting score correlated with improvement of K_trans in infliximab-treated patients and with deterioration of K_trans in placebo-treated subjects. Poor responders showed high expression of activated B-cell genes whereas good responders exhibited a gene expression pattern consistent with mobilization of neutrophils and monocytes and high levels of reticulated platelets. This gene signature was significantly associated with clinical response in two previously published whole blood gene expression studies using anti-TNF therapies. These data provide support for the hypothesis that anti-TNF inadequate responders comprise a distinct molecular subtype of RA characterized by differences in pre-treatment blood mRNA expression. They also highlight the importance of placebo controls and robust, objective endpoints in biomarker discovery.

Trial Registration: ClinicalTrials.gov NCT01313520

Iron repletion is associated with reduction in platelet counts in non-dialysis chronic kidney disease patients independent of erythropoiesis-stimulating agent use: a retrospective cohort study

Background

Iron deficiency is common in non-dialysis chronic kidney disease (ND-CKD) patients and, on occasion, requires parenteral iron therapy. We investigated the effect of intravenous iron repletion on platelet counts in ND-CKD patients with and without concomitant darbepoetin administration.

Methods

We conducted a retrospective analysis of ND-CKD patients with iron deficiency anemia treated with low molecular weight iron dextran (LMWID) between 2005 and 2009 at our CKD clinic. The primary end-point was change in platelet count 60 days post infusion of LMWID in those with and without concomitant darbepoetin administration. Secondary end-points were the correlations between changes in platelet count and iron indices.

Results

A total of 108 patients met inclusion and exclusion criteria. The decrease in platelet counts in response to iron repletion was statistically significant (305.72 ± 108.86 vs 255.58 ± 78.97, P = < .0001). The decrease in platelet count was independent of concomitant darbepoetin use. Bivariate regression analysis between baseline platelet count and transferrin saturation by iron (TSAT) showed a negative association (β_TSAT = −5.82, P = .0007) and moderate correlation (R = 0.32). Following iron treatment, the within individual changes in platelet count in 60 days were not related to changes in TSAT (β_ΔTSAT = −0.41, P = .399) and demonstrated a poor correlation (R = 0.10).

Conclusions

Parenteral iron treatment by LMWID is associated with reduction in platelet counts in iron deficient anemic ND-CKD patients. However, ESA use in the majority of patients prior to intravenous iron administration could have altered platelet production through bone marrow competition.

Reactive thrombocytosis accompanying subclinical hypothyroidism due to Hashimoto's thyroiditis

The important thing in a patient in whom platelet values were detected to be greater than normal is whether thrombocytosis is a reactive phenomenon due to a different pathology or due to a clonal hematological pathology. In this case report, reactive thrombocytosis observed in a case with subclinical hypothyroidism due to Hashimoto's thyroiditis is reported; and according to our literature review, this is the first reported case of reactive thrombocytosis due to Hashimoto's thyroiditis and/or subclinical hypothyroidism. A 31-year-old man without any complaint was admitted to the Hematology Department for thrombocytosis which was detected in his routine follow-up. He had been using thyroid hormone replacement for 2 years because of hypothyroidism as Hashimoto's thyroiditis was earlier diagnosed. Due to miscommunication, he stopped his medication levothyroxine 0.1 mg/day 2 weeks in advance and he was still off-drug on admission. Platelet count was 715×10/l in the first admission center. Subclinical hypothyroidism diagnosis was made with the present findings and thyroid hormone replacement therapy was again commenced gradually. Platelet counts and thyroid-stimulating hormone value were normal 6 weeks later. As a result, before making diagnosis of thrombocytosis related to myeloproliferative disease or myelodysplastic syndromes, secondary causes should be investigated carefully.

Changes in platelet count and mean platelet volume during infectious and inflammatory disease and their correlation with ESR and CRP

BACKGROUND

The measurements of platelet count and mean platelet volume (MPV) are routinely available nowadays. The aim of this study was to evaluate the platelet count and MPV trend in infectious and inflammatory processes. We also investigated whether these parameters were associated with the known markers of disease activity, erythrocyte sedimentation rate (ESR) and C- reactive protein (CRP).

METHODS

This cross-sectional study was conducted on 100 children with diagnosis of infectious and inflammatory diseases. Platelet count, MPV, ESR, and CRP were measured at the time of hospitalization and thereafter in the recovery phase.

RESULTS

Mean platelet count increased in the patients at the time of admission in the hospital compared to the recovery and discharge time (mean 430,820 ± 134,643/μl vs. 350,970 ± 99,374/μl, P < 0.001). However, MPV decreased significantly during the same period (8.2 ± 1.1 fl vs. 8.7 ± 0.9, P < 0.001). Platelet count was directly correlated with CRP (mean 6.4 ± 0.3 mg/l), (r = 0.49, P < 0.001) and ESR (mean 10.9 ± 1.1 mm/hr), (r = 0.32, P = 0.003). On the other hand, MPV was inversely correlated with CRP (r = 0.39, P < 0.001) and ESR (r = -0.24, P = 0.034).

CONCLUSIONS

This study demonstrated a higher level of platelet count and lower MPV in the patients with active disease compared to the recovered patients. These parameters were well correlated with the known disease activity markers. We propose that platelet parameters can be considered as reliable markers for assessment of disease activity and response to treatment.

Thrombocytosis: diagnostic evaluation, thrombotic risk stratification, and risk-based management strategies

Thrombocytosis is a commonly encountered clinical scenario, with a large proportion of cases discovered incidentally. The differential diagnosis for thrombocytosis is broad and the diagnostic process can be challenging. Thrombocytosis can be spurious, attributed to a reactive process or due to clonal disorder. This distinction is important as it carries implications for evaluation, prognosis, and treatment. Clonal thrombocytosis associated with the myeloproliferative neoplasms, especially essential thrombocythemia and polycythemia vera, carries a unique prognostic profile, with a markedly increased risk of thrombosis. This risk is the driving factor behind treatment strategies in these disorders. Clinical trials utilizing targeted therapies in thrombocytosis are ongoing with new therapeutic targets waiting to be explored. This paper will outline the mechanisms underlying thrombocytosis, the diagnostic evaluation of thrombocytosis, complications of thrombocytosis with a special focus on thrombotic risk as well as treatment options for clonal processes leading to thrombocytosis, including essential thrombocythemia and polycythemia vera.

C-reactive protein as an outcome predictor for percutaneous transluminal angioplasty in diabetic patients with peripheral arterial disease and infected foot ulcers

AIM

Although percutaneous transluminal angioplasty (PTA) is an effective therapeutic procedure for critical limb ischemia, several clinical factors can influence the outcome of PTA for peripheral arterial disease (PAD). The aim of this study is to identify the outcome predictors of PTA in infected diabetic foot patients with PAD.

METHODS

Eighty-five diabetic patients with a total of 90 infected limbs treated by PTA participated in this study. Patients were initially admitted for infected foot ulcers and were later diagnosed with PAD. Even though all patients underwent successful PTA within 15 days of admission, limb salvage was successful in 66 cases while 24 underwent subsequent amputation. The clinical characteristics and laboratory variables of both groups before PTA were compared and analyzed.

RESULTS

Significantly higher level of C-reactive protein (CRP) was observed in the major amputation group before PTA. The cutoff value via receiver operating characteristic curve was 50mg/L (81.8% specificity, 70.7% sensitivity). Multivariate logistic regression analysis revealed that CRP levels may serve as valuable marker in determining a successful outcome.

CONCLUSION

Reduced CRP levels (<50mg/L), which indicates a low infection severity, may serve as a major predictor of successful PTA outcome in diabetic patients with infected foot ulcers.

Thrombocytosis in liver transplant recipients: prevalence, natural history, and impact

The prevalence, natural history, and implications of reactive thrombocytosis after liver transplantation (LT) are unknown. Prospectively collected data from July 2000 to February 2006 were analyzed. Post-LT thrombocytosis was defined as a platelet count of > 450 x 10(3)/microL lasting for >7 days and starting within 8 weeks of transplantation. In patients who survived >8 weeks, graft and patient outcomes were compared with liver transplant recipients who survived >8 weeks and did not develop any thrombocytosis. Post-LT thrombocytosis was seen in 92 (14.7%) of 627 patients. The median onset was on day 13 (range, days 1-44) and the peak platelet count was seen on day 17 (range, days 3-110). The median duration of thrombocytosis was 25 days (range, 7-1,253 days), with a median peak platelet count of 625 x 10/microL (range, 472-1,381 x 10/microL). Seronegative fulminant hepatic failure was the indication for transplantation in 18% of patients with post-LT thrombocytosis compared with 3% of controls (P < 0.001). There was a lower proportion of patients transplanted for hepatitis C-related cirrhosis in the thrombocytosis group (10% vs. 18%, P = 0.04). The occurrence of hepatic arterial thrombosis was similar in the 2 groups (5% vs. 4%, P = NS). None of the 4 patients with platelet count higher than 1,000 x 10/microL developed thrombotic complications. Post-LT thrombocytosis is more often associated with seronegative fulminant hepatic failure, and there is a negative association with hepatitis C-related cirrhosis. Post-LT thrombocytosis does not increase the risk of hepatic artery thrombosis, and patients without thrombotic complications should not be treated.

Thrombocytosis in Pediatric Patients Is Associated with Severe Lower Respiratory Tract Inflammation

BACKGROUND

Secondary thrombocytosis is associated with a variety of clinical conditions. The aim of this study was to determine the incidence and to analyze the clinical significance and prognostic value of thrombocytosis in lower respiratory tract infection.

METHODS

A total of 102 pediatric patients were hospitalized with lower respiratory tract infection during a period of 30 months.

RESULTS

Forty nine (48%) of those patients had platelet counts >500 x 10(9)/L. The median age of the thrombocytotic patients was 31 months as opposed to 61 months for the non-thrombocytotic ones. The patients with thrombocytosis had more serious illness. This is indicated by three factors: more severe clinical condition on admission, presence of respiratory distress and longer hospitalization. Sedimentation rate >70 mm/h was observed in 44.4% patients of the thrombocytotic group compared to only 27.7% of the non-thrombocytotic ones. Almost all patients with pleural effusion were thrombocytotic. The children with very high platelet counts >650 x 10(9)/L presented with respiratory distress on admission and required longer hospitalization time. No other significant clinical or laboratory differences were demonstrated between these patients and the remainder of the thrombocytotic patients.

CONCLUSIONS

Thrombocytosis is a common finding among patients with lower respiratory tract infection. Thrombocytotic patients have a more severe clinical condition. Importantly, thrombocytosis occurs almost exclusively in patients with pleural effusion. The platelet count may be a useful clinical marker associated with the severity of the lower respiratory tract infection.

Involution of thymus and lymphoid depletion in mice expressing the hTNF transgene

Tumour necrosis factor (TNF) is involved in the pathogenesis of several diseases. In mice, human TNF signals only through p55, one of two murine TNF receptors. We here report a study of growth, viability and morphological alterations in transgenic mice expressing a low constitutive and tissue-restricted level of human TNF in vivo. The transgene was expressed solely in T cells. The transgenic mice showed a marked failure to thrive and a rapid cellular depletion in spleen and thymus. Slight fibrosis was seen in most tissues investigated, in addition to immature adipose tissue and irregular lymphocytic areas. Serum levels of hTNF were only slightly increased in the transgenic mice, enough, however, to cause an inflammatory reaction. All the symptoms were abrogated by an inhibitory hTNF antibody, demonstrating the essential role of hTNF in this phenotype. Transgenic mice constitute a multidimensional system allowing observation of disease processes over time in all tissues. The effects of hTNF were seen first and foremost in the lymphoid organs of the transgenic mice, verifying their cells as major targets at low levels of hTNF expression in the T-cell compartments. Chronic, low levels of TNF expression cause profound disturbances in lymphoid tissue development resulting in cachexia and premature death.

Interleukin-1beta up-regulates the expression of thrombopoietin and transcription factors c-Jun, c-Fos, GATA-1, and NF-E2 in megakaryocytic cells

The multifunctional cytokine interleukin-1beta (IL-1beta) plays a central role in the body's immune and inflammatory responses. The mechanism of IL-1beta on thrombocytosis and megakaryocytopoiesis has remained controversial. In previous reports, we have demonstrated the expression of IL-1 receptors (IL-1RI and IL-1RII) and enhancing effects of IL-1beta on primary human megakaryocytic (MK) cells. In this study, we investigated the possible direct effects of IL-1beta on the expression of thrombopoietin (TPO) and transcription factors c-Jun, c-Fos, GATA-1, and p45 nuclear factor-E2 (NF-E2) in MK cell lines CHRF and Meg-01. Our results demonstrated that IL-1beta up-regulated messenger RNA (mRNA) and protein expressions of these transcription factors in a dose- and time-dependent manner. In CHRF cells, mRNA: c-Jun [3.4-fold, peaked at 15 minutes], c-Fos [4.2-fold, 15 minutes], GATA-1 [4.0-fold, 60 minutes], NF-E2 [3.2-fold, 120 minutes] and protein expression: c-Jun [3.0-fold, 30 minutes], c-Fos [1.7-fold, 30 minutes], GATA-1 [11.5-fold, 60 minutes], NF-E2 [12.5-fold, 120 minutes] were evidently enhanced after treatment with IL-1beta. The response to IL-1beta was consistent in the total cell and nuclear extracts and was significantly reduced by pretreatment with actinomycin D or cycloheximide. An IL-1-receptor antagonist (IL-1RA) inhibited the stimulatory effects of IL-1beta on these transcription factors by as much as 78%. TPO expression was increased by more than 9.9-fold on stimulation with IL-1beta. A TPO-neutralizing antibody did not significantly reduce the effects of IL-1beta. We conclude that IL-1beta up-regulates the expression of TPO, c-Jun, c-Fos, GATA-1, and NF-E2 in MK cells. The mechanism might be mediated by IL-1beta receptors and require transcription or protein synthesis. The direct involvement of IL-1beta in the MK lineage may provide an explanation for the phenomenon of thrombocytosis during inflammatory responses.

Levels of serum cytokines and acute phase proteins in patients with essential and cancer-related thrombocytosis

Essential thrombocytosis (ET) is a myeloproliferative disorder resulting in an increased production of abnormal platelets. Reactive thrombocytosis (RT) is occasionally observed in clinical situations including chronic inflammation and malignancy. The aim of the present study was to evaluate the discriminatory efficiency of various laboratory tests in patients with ET and cancer-related RT. Forty-five patients with ET, 52 patients with RT, and 25 age-matched normal individuals comprised the study population. Plasma interleukin-1 alpha (IL-1a), IL-2, IL-6, tumor necrosis factor alpha (TNF-a), platelets, hematocrit, hemoglobin, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), lactate dehydrogenase (LDH) and ferritin were determined. We found increased levels of ferritin, LDH, CRP, ESR, IL-1a, and IL-6 in RT compared with ET (p < 0.01 to p < 0.0005). Hemoglobin, hematocrit, and platelets were significantly lower in RT than in ET (p < 0.0005). Furthermore, ferritin and ESR were negatively correlated with Hct, hemoglobin, and TNF-a, whereas ferritin was positively correlated with ESR, IL-1a, IL-6, and CRP, and IL-1a was positively correlated with IL-6. We consider that the aforementioned parameters should be included in the investigation of unexplained thrombocytosis for the differentiation of essential from cancer related thrombocytosis.

Pathologic thrombopoiesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is frequently complicated by thrombocytosis correlated with disease activity. The exact pathogenetic mechanism(s) that cause increased platelet counts in RA are still unknown. Recent investigations indicate that proinflammatory pleiotropic cytokines of RA also have megakaryocytopoietic/thrombopoietic properties. Moreover, several lineage-dominant hematopoietic cytokines can also act as acute phase responders and contribute to the inflammation. This review focuses on the current literature and our experience regarding the dual relationships of the pathologic thrombopoiesis of RA. Growth factors contributing to it, namely interleukin (IL)-6, IL-11, stem cell factor, leukemia inhibitory factor, granulocyte colony stimulating factor, thrombopoietin (TPO), and the regulation of megakaryocytopoiesis during the inflammatory cascade are reviewed. Some data indicate that thrombopoietin could contribute to the reactive thrombocytosis of RA. In the non-lineage-specific gp130 cytokine family, IL-6 appears to predominate for the induction of megakaryopoiesis. However, other cytokines and growth factors may also contribute to the pathologic megakaryocytopoiesis of RA. Those pleiotropic mediators seem to act in concert to regulate this enigmatic process. Clarification of the pathobiologic basis of thrombopoiesis in RA may improve understanding of the disease pathogenesis and management of the inflammatory thrombocytosis.

Serum proinflammatory cytokines and its relationship to clinical parameters in lung cancer patients with reactive thrombocytosis

Proinflammatory cytokines Interleukin-1 beta (IL-1 beta) and Interleukin-6 (IL-6) play a significant role in the pathogenetic processes related to various malignant and inflammatory conditions. Leukocytosis, thrombocytosis and increased acute phase protein levels are part of a systemic inflammatory response. In this study, we measured the concentrations of IL-1 beta, IL-6 and ferritin as well as hemoglobin, lactate dehydrogenase (LDH), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in 23 patients (male 15, female 8, median age 68 years) with lung cancer and reactive thrombocytosis (LCRT), in 27 (male 18, female 9, median age 64 years) with benign inflammatory lung disorder (BILD) and 18 (male 10, female 8, median age 62 years) lung cancer patients with a normal platelet count (LCNP). IL-1 beta levels were significantly higher in the three patient groups in comparison with control subjects (P < 0.001) but without significant difference among the three patient groups. IL-6 was higher in all three patients groups but only in the BILD group it was significantly higher than the control group (P < 0.05). However, no significant difference in IL-6 serum levels was found between the two lung cancer groups. CRP and LDH were significantly higher in the LCRT group in comparison with the other two patient groups (P < 0.01 and 0.001, respectively), while ferritin was higher in both lung cancer groups in comparison with the BILD group (P < 0.001). Our data suggest that in lung cancer patients, reactive thrombocytosis is part of the systemic inflammatory reaction for which IL-1 beta and IL-6 may be intermediate but not independent mediators.

Assessment of platelet numbers and morphology in the peripheral blood smear

Automated systems are currently in widespread use for the assessment of patients' complete blood counts. The evaluation of the peripheral blood smear, however, still constitutes a pivotal tool in the evaluation of patients with hematologic disorders. This article focuses on disorders affecting the number or morphology of platelets as assessed by evaluation of a peripheral blood smear and also outlines some of their important clinical findings.

Expression of interleukin (IL) 1 type I and type II receptors in megakaryocytic cells and enhancing effects of IL-1beta on megakaryocytopoiesis and NF-E2 expression

Megakaryocytopoiesis is regulated by thrombopoietin (TPO) and cytokines such as interleukin 3 (IL-3), IL-6 and IL-11. This study investigated the in vitro effects of IL-1beta on megakaryocytopoiesis and the expression of IL-1 type I and type II receptors (IL-1 RI and RII) on mega-karyocytic cell lines and primary cells. Our results demonstrated that IL-1beta alone or in combination with TPO induced megakaryocyte colony forming units (CFU-MK) from murine and human haematopoietic cells. Using reverse-transcription polymerase chain reaction (RT-PCR) and Southern hybridization techniques, the mRNA of IL-1beta, IL-1 RI, IL-1 RII and the transcription factor NF-E2 were detected in CD61+ CD41+ cells cultured from cord blood and four megakaryocytic cell lines, Meg-01, DAMI, CHRF-288-11 and M-07e. The expression of IL-1 RI and RII proteins was confirmed by flow cytometry and immunofluorescence staining. In Meg-01 cells, the expression of NF-E2 was increased at both mRNA and protein levels after treatment with IL-1beta for 4 h. This study demonstrated for the first time the presence of IL-1 receptors on megakaryocytic cells and the induction of NF-E2 by IL-1beta. The mitogenic effect of IL-1beta on this lineage could be mediated through IL-1 receptors and the activation of NF-E2.

Inflammation, obesity, stress and coronary heart disease: is interleukin-6 the link?

There is mounting evidence that inflammation plays a role in the development of coronary heart disease (CHD). Observations have been made linking the presence of infections in the vessel wall with atherosclerosis, and epidemiological data also implicate infection in remote sites in the aetiology of CHD. In this article we propose a key role for the proinflammatory cytokine interleukin-6 (IL-6) in several mechanisms that contribute to the development of CHD. IL-6 is a powerful inducer of the hepatic acute phase response. Elevated concentrations of acute phase reactants, such as C-reactive protein (CRP), are found in patients with acute coronary syndromes, and predict future risk in apparently healthy subjects. The acute phase reaction is associated with elevated levels of fibrinogen, a strong risk factor for CHD, with autocrine and paracrine activation of monocytes by IL-6 in the vessel wall contributing to the deposition of fibrinogen. The acute phase response is associated with increased blood viscosity, platelet number and activity. Furthermore, raised serum amyloid A lowers HDL-cholesterol levels. IL-6 decreases lipoprotein lipase (LPL) activity and monomeric LPL levels in plasma, which increases macrophage uptake of lipids. In fatty streaks and in the atheromatous 'cap' and 'shoulder' regions, macrophage foam cells and smooth muscle cells (SMC) express IL-6, suggesting a role for this cytokine along with interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-alpha), in the progression of atherosclerosis. Both these cytokines induce the release of IL-6 from several cell types, including SMC. During vascular injury SMC are exposed to platelets or their products, and cytokine production by SMC further contributes to vascular damage. Furthermore, circulating IL-6 stimulates the hypothalamic-pituitary-adrenal (HPA) axis, activation of which is associated with central obesity, hypertension and insulin resistance. Thus we propose a role for IL-6 in the pathogenesis of CHD through a combination of autocrine, paracrine and endocrine mechanisms. This hypothesis lends itself to testing using interventions to influence IL-6 secretion and actions.

A combination of megakaryocyte growth and development factor and interleukin-1 is sufficient to culture large numbers of megakaryocytic progenitors and megakaryocytes for transfusion purposes

Chemotherapy-induced thrombocytopenia is a major risk factor in cancer treatment. The transfusion of autologous ex vivo expanded megakaryocytes could be a new therapy to shorten the period of thrombocytopenia. Therefore we investigated, in a liquid culture system, the effect of various cytokine combinations composed of pegylated megakaryocyte growth and development factor (PEG-rHuMGDF), interleukin-1 (IL-1), IL-3, IL-6, IL-11 and stem cell factor (SCF) on the proliferation and differentiation of CD34+ cells, in order to define the most optimal and minimum levels of cytokine combinations for megakaryocyte expansion. Besides PEG-rHuMGDF, IL-1 was found to be important for optimal megakaryocyte expansion. Depletion of either SCF, IL-6 or IL-11 did not exert a large effect, but the absence of IL-1 strongly diminished the number of megakaryocytic cells. Addition of IL-3 to the combination PEG-rHuMGDF, IL-1, IL-6, IL-11 and SCF significantly reduced the number of megakaryocyte progenitors (CD34+CD41+ cells) and the number of CFU-Meg. Furthermore, we found a strong correlation between the number of CD34+CD41+ cells and the number of CFU-Meg obtained after 8 d culture. Our study shows that optimal ex vivo expansion of megakaryocytes is achieved by the combination of PEG-rHuMGDF and IL-1. The numbers of megakaryocytes and megakaryocyte progenitors (CD34+CD41+) obtained in our liquid culture system with the growth factor combination PEG-rHuMGDF and IL-1 are suitable for transfusion purposes.

Role of TNFR1 and TNFR2 in TNF-Induced Platelet Consumption in Mice

An injection of TNF in mice induced profound thrombocytopenia, due to an increase of platelet consumption, that was evident after 1 h and lasted for 3 days. This process was evident in mice that were genetically deficient in TNFR2 (p75) but not in mice lacking TNFR1 (p55), indicating that the process is mediated by TNFR1-bearing cells. To explore the site of action of TNF, labeled platelets from TNFR1 −/− or +/+ donors were transferred to TNFR1 −/− or +/+ recipients. TNF induced the consumption of platelets from TNFR1 −/− donors when injected into +/+ recipients, while platelets from +/+ donors were not consumed when present in TNFR1 −/− recipients; this finding indicates that TNF acts on the TNFR1 of host cells but does not act on platelets. The expression of TNFRs is consistent with this interpretation, since TNFRs were not detected on platelets by flow cytometry. In megakaryocytes, the expression of TNFR1 was detected by immunohistochemistry. These results indicate that TNF induces platelet consumption by acting not on platelets directly but on the TNFR1 of other cells, presumably increasing the release of factors with agonist activity for platelets.

Cytokines affecting megakaryocytopoiesis in rheumatoid arthritis with thrombocytosis

Particular interleukins, namely interleukin (IL)-6, IL-4 and IL-1, with pro-inflammatory mediator activities have also been shown to be involved in the regulation of megakaryocytopoiesis. As rheumatoid arthritis (RA) is not uncommonly associated with reactive thrombocytosis, we investigated serum IL-1 alpha, IL-1 beta, IL-4 and IL-6 concentrations in RA patients with marked thrombocytosis, and compared them to the levels in RA patients with normal platelet counts and healthy volunteers. IL-1 beta. IL-4 and IL-6 concentrations were found to be correlated with the disease activity in both groups of RA patients, with higher serum levels of each cytokine in the thrombocythaemic group. Significant positive correlations of IL-1 beta and IL-4 with the platelet counts were documented only in patients with thrombocytosis. According to our results. IL-6 and IL-1 beta were found to be good indicators of disease activity in RA, while IL-1 beta and IL-4 seemed to be related more with the process of reactive thrombocytosis secondary to rheumatoid inflammation.