Mean Serum Levels Of Interleukin-6 Research Articles

Relationship among serum levels of IL-6, sIL-6R, s gp130 and CD126 on T-cell in HIV-1 infected and uninfected men participating in the Los Angeles Multi-Center AIDS Cohort Study.

Interleukin 6 (IL-6) activates cells through its unique heterodimeric signaling complex of IL-6 receptor (IL6R) subunit and interleukin 6 signal transducer β-subunit glycoprotein 130 (gp130). The objective of this study was to investigate associations among serum levels of IL-6, sIL-6R, sgp130 and relative fluorescence intensity (RFI) of the α-subunit of the IL-6 receptor (CD126) on T-cells of HIV-1 infected and uninfected men. Blood samples were obtained from 69 HIV-1-infected men on Highly Active Antiretroviral Therapy (HAART) with mean age of 49.1 and 52 HIV-1-uninfected with mean age of 54.3 years -. All men were participating in the Los Angeles Multi-Center AIDS Cohort Study (MACS). Serum levels of IL-6, sIL-6R, sgp130 were measured by enzyme-linked immunoassays and T-cell phenotypic analysis and RFI of CD126 on CD4+ and CD8+ by flow cytometry. Mean serum levels of IL-6, sIL6R, sgp130 and of CD126 RFI on CD4+ were 4.34 pg/mL, 39.3 ng/mL, 349 ng/mL and 526 RFI respectively for HIV-1-infected men and 2.74 pg/mL, 41.9 ng/mL, 318 ng/mL and 561 RFI respectively for HIV-1-uninfected men. The mean serum concentrations of IL-6, sIL-6R in HIV-1-infected and uninfected men were not significantly different (p>0.05). There was a positive correlation between plasma HIV-1 RNA and the levels of IL-6 (p<0.001), sIL6R (p = 0.002) but no correlation with sgp130 (p = 0.339). In addition, there was a negative correlation between serum levels of IL-6 with RFI of CD126 on CD4+ (p = 0.037) and a positive correlation between serum levels of sgp130 (p = 0.021) and sIL-6R in HIV-1-infected men. Knowledge of biological variation, differences in the blood levels of biomarkers among healthy individuals and individuals experiencing illness, are very important for selection of appropriate tests for stage and progression of disease. Our data suggest no correlation among IL-6, and sIL-R6, in the treated phase of HIV-1 infection. The action and blood level of IL-6 and its receptors may be different at each stage of a disease progression.

Role of interleukin 4 (IL4) and interleukin 6 (IL6) in the pathogenesis and prognosis of childhood primary immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by the breakdown of immune tolerance. Impairment of the cellular immunity is primarily evaluated by the levels of the cytokines which can help in predicting the course of ITP. We aimed to assess the levels of IL4 and IL6 in children with ITP and evaluate their role in the pathogenesis and prognosis of this disease. A prospective cohort study was carried on 60 children (15 patients with newly diagnosed ITP, 15 patients with persistent ITP, 15 patients with chronic ITP and 15 healthy children as a control group). Serum IL-4 and serum IL-6 were measured using Human IL-4 and IL-6 ELISA kit in patients and controls. Patients with newly diagnosed and persistent ITP had significantly higher levels of IL4 and IL6 compared to patients with chronic ITP and healthy controls (p < 0.001). The mean serum level of IL4 was 762.0, 741.0, 364.6 and 436.8 pg/ml, and the mean serum level of IL6 was 178.5, 164.4, 57.9 and 88.4 pg/ml for patients with newly diagnosed, persistent, chronic ITP and healthy controls respectively. Serum IL-4 was significantly higher in patients who achieved remission than those who did not improve on first line therapy.Conclusion: Serum IL-4 and IL-6 may have a role in the pathogenesis of primary ITP. IL-4 seems to be a good predictor to treatment response.What Is Known:• There is a delicate balance of specific cytokine levels in immune thrombocytopenia, which has an important role in the immune system and is known to be deregulated in autoimmune diseases. changes in IL-4 and IL-6 might be involved in the pathogenesis of newly diagnosed ITP in both paediatric and adult patients.• We conducted this research study to measure the serum level of IL-4 and IL-6, in newly diagnosed, persistent and chronic ITP patients and study their relation to disease pathogenesis as well as patient’s outcome.What Is New:• We found that IL4 seems to be a good predictor to treatment response and it was a very interesting observation in our study, and to the best of our knowledge, there is no published data about this finding.

Pentoxifylline effects on hospitalized patients with COVID19: A randomized, double-blind clinical trial

Pentoxifylline (PTX) has broad-spectrum properties such as anti-inflammatory, anticoagulant, and antiviral effects. The aim of this study was to evaluate the efficacy and safety of PTX in hospitalized patients with COVID-19.This double-blind, placebo-controlled randomized clinical trial was conducted on hospitalized patients with COVID-19. The recruited patients were randomly (1:1) assigned to the PTX group and the placebo group. The intervention group received PTX capsules at a dose of 400 mg three times a day for 10 days along with the national regimen, including interferon plus lopinavir/ritonavir and hydroxychloroquine. The primary outcome was the improvement of clinical scores. The secondary outcomes, on the other hand, were improvement in inflammatory and oxidative stress factors and hospital complications.From a total of 102 patients who met the inclusion criteria, 72 individuals completed the study and were analyzed. No significant differences were shown in demographics and baseline clinical characteristics. Clinical scores was not significant between the two groups (P = 0.31 and 0.07 for day 5 and 11, respectively). Although the mean serum levels of interleukin-6 (IL-6) and glutathione changed significantly after 5 days in the PTX group (P = 0.03 and p = 0.04), ICU admission, intubation, and hospital stay did not differ between the two groups.The results of our study did not show any superiority of PTX over placebo in improving the clinical outcomes of patients with COVID-19. Although PTX had a beneficial effect on IL-6 and showed an acceptable safety profile, it did not offer any clinical benefit for COVID-19 complications.

The Effect of Melatonin on the Serum Level of Interleukin 6 and Interleukin 9 in Coronary Artery Bypass Grafting Surgery.

Cardiopulmonary bypass has been recognized as one of the main causes of systemic inflammatory response syndrome, leading to post-operative complications. The aim of this study was to investigate the effect of melatonin on the serum levels of interleukin 6 (IL-6) and IL-9 in patients undergoing coronary artery bypass grafting surgery. Forty-four patients undergoing elective coronary artery bypass surgery were randomly allocated into two study groups of melatonin (n = 23) and placebo (n = 21). Patients in the melatonin group received two melatonin tablet, 5 mg daily for 3 days before surgery, 10 mg tablet (two doses of 5 mg) 1 h before induction of anesthesia and finally, 10 mg melatonin tablet in the intensive care unit, placebo group patients received placebo at the same time periods. Serum levels of IL-9 and IL-6 were measured as baseline (T1), before induction of anesthesia (T2), 6 and 24 h after off pump (T3, T4). Data were analyzed using SPSS 23 software (IBM Corp., Armonk, NY, USA). The mean serum level of IL-6 was significantly lower in the melatonin group at T3 and T4 (p ＜ 0.05). Also, in both groups, serum levels of IL-6 in T3 showed a significant increase compared to T1. Serum levels of IL-9 had no significant difference between the two groups at T1, T2, T3, and T4. The results of this study showed that pre-operative melatonin administration could modify inflammatory cytokines secretion such as IL-6 while it has no significant effect on the serum levels of IL- 9. Neither of the changes was clinically significant.

Serum Levels of Interleukin-6 and Tumor Necrosis Factor Alpha in Children With Attention-Deficit Hyperactivity Disorder.

ABSTRACTBackground:Attention-deficit hyperactivity disorder (ADHD) is a common disorder in children, but its etiology and pathogenesis are still unclear.Aims:The aims of this study were to measure the level of serum interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) as markers of immune system involvement in children with ADHD, and to study their correlation with symptoms severity of ADHD.Materials and Methods:The study was conducted on 80 children diagnosed as ADHD based on the criteria adapted from the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition. Eighty healthy children of matched age and sex served as a control group. All children enrolled in the study were subjected to history taking, clinical examination, and psychometric tests. Assay for serum IL-6 and TNF-α for all patients and controls was performed using enzyme-linked immunosorbent assay.Results:The mean serum level of IL-6 was 26.11 ± 11.14 and 6.23 ± 2.52 in children with ADHD and controls, respectively. Children with ADHD showed significantly higher serum IL-6 levels than the control group (P = 0.001). Serum IL-6 showed no significant correlation with the intelligence quotient (IQ) or the Abbreviated Conners’ Rating Scale scores for parents. However, TNF-α showed no significant differences between the two groups and no significant correlation with the IQ or the Abbreviated Conners’ Rating Scale scores for parents.Conclusion:Serum IL-6 levels were significantly higher in children with ADHD compared to controls; however, the IL-6 levels did not correlate with ADHD symptoms severity. Increased IL-6 levels may contribute to the etiology of ADHD.

Effect of long-term occupational exposure to extremely low-frequency electromagnetic fields on proinflammatory cytokine and hematological parameters

Purpose: The present study aimed to investigate the effect of extremely low-frequency electromagnetic fields (ELF-EMFs) on proinflammatory cytokines and hematological parameters, among the employees of a power plant, which are one of the most important occupational groups exposed to ELF-EMFs extensively.Materials and methods: The studied population included 112 employees of a power plant as the exposed group and 138 unexposed employees who were enrolled based on inclusion and exclusion criteria. The magnetic flux density and the strength of the electric field were determined by spot measurements and according to the IEEE C95.3.1 standard. Proinflammatory cytokines including serum interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α); and hematologic parameters of all subjects were measured.Results: The mean level of IL-1β and IL-6, white blood cell count (WBC) and red blood cell count (RBC), lymphocyte percentage (Lym%), mean corpuscular volume (MCV), platelet count (PLT) and procalcitonin (PCT) were significantly more in the exposed group, than the unexposed group. The mean serum levels of IL-6, IL-1β and some of the hematological parameters including WBC, lymphocyte, RBC and hematocrit were higher in technicians which had the highest level of exposure to magnetic fields compared to other groups and these relations were linear.Conclusions: Long-term exposure to ELF-EMFs probably affects immune responses, by stimulating the production of proinflammatory cytokines, and increasing some hematological parameters.

Impact of resveratrol supplementation on inflammatory, antioxidant, and periodontal markers in type 2 diabetic patients with chronic periodontitis

BackgroundDiabetes mellitus and periodontal disease are two common and chronic diseases with bidirectional relationship influence public health and quality of life. The aims of this study was to study the impact of resveratrol supplementation in adjunct with non-surgical periodontal therapy on inflammatory, antioxidant, and periodontal markers in patients with type 2 diabetes with periodontal disease. Materials and methodsIn this randomized clinical trial, 43 patients with diabetes and chronic periodontitis were randomly allocated into two intervention and control groups receiving either resveratrol supplements or placebo for 4 weeks. Serum levels of interleukin 6 (IL6), tumor necrosis factor α (TNFα), total antioxidant capacity (TAC) and clinical attachment loss (CAL) as the main index of periodontal marker were measured pre-intervention and post-intervention. ResultsIn the intervention group, the mean serum level of IL6 was reduced significantly (P = 0.039) post-intervention (2.19 ± 1.09 and 1.58 ± 1.06). No significant differences were seen in the mean levels of IL6, TNFα, TAC and CAL between two groups post-intervention. ConclusionsIt is suggested that daily consumption of resveratrol supplement may not change TNFα, TAC and CAL, but it would be beneficial in reducing serum levels of IL6. Therefore, further studies are suggested to investigate the effects of resveratrol supplementation along with NST on periodontal status.

Serum Interleukin-6 Level in Children With Attention-Deficit Hyperactivity Disorder (ADHD).

Attention-deficit hyperactivity disorder (ADHD) is a common neurobehavioral disorder in children, but its specific etiology and pathophysiology are still incompletely understood. This case-control study aimed to measure the level of serum interleukin-6 (IL-6) as a predictor of the immunologic status in children with ADHD, and to study its correlation with severity of symptoms. 60 ADHD children who met the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, criteria for ADHD and 60 control children were subjected to complete history taking, clinical examination, and psychometric tests. Serum interleukin-6 of ADHD patients and control children was measured by enzyme-linked immunosorbent assay. The mean serum level of IL-6 was 22.35 (95% confidence interval [CI], 17.68-26.99) in ADHD patients, and it was 5.44 (95% CI, 4.81-6.06) in controls. A significantly higher level of IL-6 was reported in ADHD patients compared with controls ( P = .001). No significant correlation was found between serum IL-6 level and either the Intelligence Quotient (IQ) or the Conners' Parent Rating Scale score. Serum IL-6 values were significantly higher in ADHD patients compared to healthy control children. Increased production of IL-6 may play a role in the pathogenesis of ADHD.

Evaluation of pro-inflammatory cytokines in nutritionally stunted Egyptian children

ObjectivesStunting affects 32% of children living in developing countries and has a major impact on child health and development. In this study, we aimed to assess the pro-inflammatory cytokines and some micronutrients among the healthy control and nutritionally stunted Egyptian children. Subjects and methodsA total of 88 children were enrolled; 60 stunted children and 28 non-stunted of matched age and sex. Clinical, demographic characteristics, serum levels of calcium, magnesium, and zinc were measured. Plasma levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNFα) and C – reactive protein (CRP) were measured in these subjects. ResultsStunted children showed a marked decrease in weight and weight-for-age Z score (WAZ) versus healthy one. Significant reduction in the serum level of Ca, Mg, and Zn was detected in stunted children compared to those of the healthy control subjects. Moreover, the mean serum levels of IL-6 (pg/ml) (1.5 Vs 1.6), TNFα (pg/ml) (1.7 Vs 1.8) and CRP (mg/l) (0.7 Vs 1) were significantly higher among the stunted group compared to control. ConclusionNutritionally stunted Egyptian children have lowered serum levels of Zn. Ca, and Mg, in addition to elevated serum levels of proinflammatory cytokines (Il-6, TNFα, and CRP).

Serum Levels of Interleukin-6 and Interleukin-10 as Biomarkers for Hepatocellular Carcinoma in Egyptian Patients.

Interleukin-10 (IL-10) and interleukin-6 (IL-6) have been reported to be related to hepatocellular carcinoma (HCC) prognosis. This study aimed to investigate the clinical usefulness of serum levels of IL-6 and IL-10 as biomarkers for HCC among high-risk patients. Materials and Methods. 80 individuals were enrolled in this study; they were categorized into 4 groups: group 1 healthy individuals (NC) (n = 20), group 2 chronic hepatitis C virus (HCV) patients (n = 20), group 3 cirrhotic patients (LC) (n = 20), and HCC group (n = 20). Using ELISA technique serum levels of IL-6, IL-10, and alpha fetoprotein (AFP) were evaluated in all groups. Results. The mean serum levels of IL-6 were significantly higher in HCC than in LC, HCV, and NC groups (13.99 ± 1.80, 7.49 ± 0.43, 5.78 ± 0.74, and 2.57 ± 0.31), respectively (P < 0.05); also the serum levels of IL-10 were significantly higher in HCC compared with LC, HCV, and NC groups (13.69 ± 1.89, 7.37 ± 0.53, 5.18 ± 0.6, and 3.31 ± 0.42) (P < 0.05). We also found that the tumor size is correlated strongly with IL-6 and IL-10 levels (r = 0.925, P < 0.001; r = 0.821, P < 0.001), respectively. Conclusion. The combination of those markers may help to identify a group of HCC patients with low AFP.

Kinetics of α2-macroglobulin and α1-acid glycoprotein in rats subjected to repeated acute inflammatory stimulation

The kinetics of alpha(2)-macroglobulin (alpha2M) and alpha(1)-acid glycoprotein (AAG) in rats repeatedly stimulated with intramuscular injections of turpentine oil at doses 0.05 and 0.4 mL/rat were investigated. Mean serum levels of alpha2M peaked at 48 h after the first turpentine oil injection, reaching 1.74 and 2.36 mg/mL at 0.05 and 0.4 mL/rat, respectively. AAG peaks were also observed at 48 h after injection, and the mean values were 2.02 and 2.53 mg/mL, respectively. These peak values of alpha2M and AAG differed significantly between the 0.05 and 0.4 mL/rat injection groups. Mean serum levels of interleukin-6 (IL-6) at 0.05 mL/rat were 52.61 pg/mL at 12 h, 48.86 pg/mL at 36 h and 81.93 pg/mL at 84 h after the first injection. Mean IL-6 serum levels at 0.4 mL/rat were 215.24 pg/mL at 12 h, 56.33 pg/mL at 36 h and 39.25 pg/mL at 84 h after the first injection. Mean serum levels of cytokine-induced chemoattractant-1 (CINC-1) at a dose of 0.05 mL/rat were 5.70 ng/mL at 12 h, 5.58 ng/mL at 36 h and 4.58 ng/mL at 84 h after the first injection. Mean serum levels of CINC-1 after injection at 0.4 mL/rat were 11.57 ng/mL at 12 h, 4.68 ng/mL at 36 h and 4.42 ng/mL at 84 h. Serum levels of IL-6 differed significantly at 12, 24, 72 and 84 h, while those of CINC-1 differed significantly at 12, 24, 48 and 96 h between the 0.05 and 0.4 mL/rat injection groups. Differences in peak serum levels in the 0.05 and 0.4 mL/rat groups were attributed to differences in the production of IL-6 and CINC-1, which are thought to contribute to alpha2M and AAG production.

Effect of Weight Loss on Proinflammatory State of Mononuclear Cells in Obese Women

TO THE EDITOR: The recent article in this Journal by Sheu et al. (1) titled “Effect of Weight Loss on Proinflammatory State of Mononuclear Cells in Obese Women” addresses the important question of whether weight loss alters the proinflammatory state associated with obesity. The authors used serum levels of several proinflammatory markers such as C-reactive protein and tumor necrosis factor-α, as well as proinflammatory gene transcript levels and nuclear factor-κB (NFκB) DNA binding in peripheral blood mononuclear cells (MNCs), as biomarkers of the systemic inflammatory response. It was reported that a small degree of weight loss (5%), induced by a 12-week calorie restriction and exercise program, was associated with marked reductions in circulating levels of most proinflammatory markers (but not interleukin-6) and reduced NFκB “activity” in MNCs (1). We were rather surprised by the dramatic decrease in serum C-reactive protein levels induced by this small degree of weight loss (mean BMI following weight loss was still 30.6 kg/m), particularly when the mean serum level of interleukin-6 (the direct upstream regulator of C-reactive protein synthesis) actually increased over the same period. One speculates that a behavioral change linked to the weight loss program, such as dietary intake (2) or exercise (3), or other confounding clinical factors, rather than weight loss per se, might have contributed to the observed changes in inflammatory biomarkers. To this end, it is important to exclude nonsteroidal anti-inflammatory drug use or intercurrent infection as contributing factors in this study. It would also be interesting to analyze the same inflammatory biomarkers several weeks after the end of the weight loss program to further interpret these short-term biomarker changes. The relevance of the observed changes in transcript levels for the NFκB and IκB isoforms to downstream NFκB-dependent transcriptional activity in MNCs is uncertain, and it is unfortunate that the protein expression data were not included in the article, particularly as NFκB DNA binding data were presented. We urge caution in interpretation of quantitative changes in p65/p50 DNA binding on the basis of a mobility shift assay alone, particularly when there is variable nuclear extract loading evident and the appropriate controls are not presented. It should be noted that colorimetric NFκB DNA-binding assays are now available commercially for more accurate quantification. Finally, we note that data from lean and obese subjects (before and after weight loss) were combined for multiple correlation analyses between serum/MNC biomarkers and BMI, as well as insulin resistance. This approach is questionable as the biological relationship between these factors may alter in these different clinical contexts. The preliminary findings by Sheu et al. should now be confirmed in a well-defined cohort of obese patients undergoing a greater degree of weight loss to determine the use of MNCs for future human biomarker studies in obesity research.

Levamisole and Chinese medicinal herbs can modulate the serum interleukin-6 level in patients with recurrent aphthous ulcerations.

Recurrent aphthous ulcerations (RAU) are common oral inflammatory lesions. Interleukin-6 (IL-6) is a pro-inflammatory cytokine that has effects on cellular and humoral immunities. Previous studies have shown that the high serum IL-6 levels in some RAU patients can be reduced by drug treatment. This finding suggests that IL-6 may be a useful marker in evaluating therapeutic effects of RAU. In this study, we used a solid phase, two-site sequential chemiluminescent immunometric assay to determine the baseline serum levels of IL-6 in a group of 228 patients with RAU, erythema multiforme (EM), traumatic ulcers (TU), oral submucous fibrosis (OSF), pemphigus vulgaris (PV), or Sjögren's syndrome (SS), and in 77 normal control subjects. Some RAU patients were treated with levamisole plus Chinese medicinal herbs or levamisole only for 0.5-5 months and their serum IL-6 levels were measured after treatment. We found that about 99% of the normal control subjects and the patients with EM, TU, or OSF had a serum IL-6 level within the normal limit of 5.0 pg/ml. However, 24% (48/197) RAU patients, 14% (1/7) EM patients, 43% (3/7) PV patients, and 100% (6/6) SS patients had a serum level of IL-6 greater than 5.0 pg/ml. The mean serum level of IL-6 in patients with RAU (3.6 +/- 3.5 pg/ml, P < 0.001), minor type RAU (2.7 +/- 2.0 pg/ml, P < 0.05), major type RAU (5.2 +/- 4.6 pg/ml, P < 0.001), or herpetiform type RAU (4.1 +/- 3.8 pg/ml, P < 0.01) was higher than that in normal control subjects. The mean serum level of IL-6 in major type (P < 0.001) or in herpetiform type RAU patients (P < 0.05) was higher than that in minor type RAU patients. The mean reduction of serum IL-6 level (10.0 +/- 7.1 pg/ml) in RAU patients after treatment with levamisole plus Chinese medicinal herbs was significantly higher than that (5.1 +/- 3.7 pg/ml) in RAU patients after treatment with levamisole only (P < 0.005), suggesting that the combination therapy is superior to the single therapy of levamisole only. We conclude that levamisole and levamisole plus Chinese medicinal herbs can modulate the serum IL-6 level in RAU patients. Although the therapeutic effect of RAU can be assessed by a decrease in the frequency, duration and number of the oral ulcerations, it can also be monitored by a reduction of serum IL-6 level in RAU patients.

Circulating levels of interleukin-6 and tumor necrosis factor-alpha are elevated in primary hyperparathyroidism and correlate with markers of bone resorption--a clinical research center study.

The pathogenesis of PTH-induced bone loss is uncertain. Experimental evidence suggests that PTH induces the production by osteoblasts of the bone-resorbing cytokine, interleukin-6. We measured the circulating levels of interleukin-6, tumor necrosis factor-alpha, and interleukin-1 beta and examined their relationship to biochemical markers of bone turnover in 38 patients with primary hyperparathyroidism (7 of whom also were studied after successful parathyroid adenomectomy), 6 patients with hypoparathyroidism, and 12 subjects with normal parathyroid function. The patients with untreated primary hyperparathyroidism had mean serum levels of interleukin-6 that were 16-fold higher than control values (mean +/- SEM; primary hyperparathyroidism 18.6 +/- 2.1 pg/mL, controls 1.1 +/- 0.1; P < 0.001). Circulating levels of interleukin-6 soluble receptor (primary hyperparathyroidism 41.7 +/- 1.2 ng/ mL, controls 25.1 +/- 1.0; P < 0.001), and tumor necrosis factor-alpha (primary hyperparathyroidism 11.6 +/- 0.8 pg/mL, controls 2.5 +/- 0.2; P < 0.001) were also elevated. After successful parathyroid adenomectomy, levels of each of these cytokines fell into the normal range. The mean levels of interleukin-6, its soluble receptor, and tumor necrosis factor-alpha in the subjects with hypoparathyroidism were lower than control values (P < 0.001 for each variable). There was no difference between subjects with primary hyperparathyroidism and controls in the circulating level of interleukin-1 beta. In the subjects with untreated primary hyperparathyroidism, serum levels of interleukin-6 correlated strongly with those of intact PTH (r = 0.47, P = 0.003) and biochemical markers of bone resorption: serum deoxypyridinoline (r = 0.93, P < 0.001), serum type I collagen carboxyterminal telopeptide (r = 0.87, P < 0.001), urinary pyridinoline (r = 0.81, P < 0.001), and urinary deoxypyridinoline (r = 0.63, P = 0.005). Levels of tumor necrosis factor-alpha correlated less strongly with the same variables: PTH (r = 0.41, P = 0.01), serum deoxypyridinoline (r = 0.48, P = 0.002), serum type I collagen carboxyterminal telopeptide (r = 0.46, P = 0.004), urinary pyridinoline (r = 0.61, P = 0.008), and urinary deoxypyridinoline (r = 0.61, P = 0.007). Levels of interleukin-6 also correlated with those of tumor necrosis factor-alpha (r = 0.44, P = 0.005). Multiple regression analysis indicated that interleukin-6, but not tumor necrosis factor-alpha, was independently predictive of bone resorption. We conclude that serum levels of interleukin-6 and tumor necrosis factor-alpha are increased in patients with primary hyperparathyroidism and are normalized by successful surgical treatment. The finding that these cytokines correlate with biochemical markers of bone resorption suggests that they play a role in the pathogenesis of bone loss in primary hyperparathyroidism.