SARS-CoV-2 nucleocapsid protein, rather than spike protein, triggers a cytokine storm originating from lung epithelial cells in patients with COVID-19.

PURPOSE: The aim of this study was to elucidate the factors associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that may initiate cytokine cascades and correlate the clinical characteristics of patients with coronavirus disease 2019 (COVID-19) with their serum cytokine profiles. METHODS: Recombinant baculoviruses displaying SARS-CoV-2 spike or nucleocapsid protein were constructed and transfected into A549 cells and THP-1-derived macrophages, to determine which protein initiate cytokine release. SARS-CoV-2-specific antibody titers and cytokine profiles of patients with COVID-19 were determined, and the results were associated with their clinical characteristics, such as development of pneumonia or length of hospital stay. RESULTS: The SARS-CoV-2 nucleocapsid protein, rather than the spike protein, triggers lung epithelial A549 cells to express IP-10, RANTES, IL-16, MIP-1α, basic FGF, eotaxin, IL-15, PDGF-BB, TRAIL, VEGF-A, and IL-5. Additionally, serum CTACK, basic FGF, GRO-α, IL-1α, IL-1RA, IL-2Rα, IL-9, IL-15, IL-16, IL-18, IP-10, M-CSF, MIF, MIG, RANTES, SCGF-ß, SDF-1α, TNF-α, TNF-ß, VEGF, PDGF-BB, TRAIL, ß-NGF, eotaxin, GM-CSF, IFN-α2, INF-γ, and MCP-1 levels were considerably increased in patients with COVID-19. Among them, patients with pneumonia had higher serum IP-10 and M-CSF levels than patients without. Patients requiring less than 3 weeks to show negative COVID-19 tests after contracting COVID-19 had higher serum IP-10 levels than the remaining patients. CONCLUSION: Our study revealed that nucleocapsid protein, lung epithelial cells, and IP-10 may be potential targets for the development of new strategies to prevent, or control, severe COVID-19.

Biofilm formation is not an independent risk factor for mortality in patients with Acinetobacter baumannii bacteremia.

In the past decades, due to the high prevalence of the antibiotic-resistant isolates of Acinetobacter baumannii, it has emerged as one of the most troublesome pathogens threatening the global healthcare system. Furthermore, this pathogen has the ability to form biofilms, which is another effective mechanism by which it survives in the presence of antibiotics. However, the clinical impact of biofilm-forming A. baumannii isolates on patients with bacteremia is largely unknown. This retrospective study was conducted at five medical centers in Taiwan over a 9-year period. A total of 252 and 459 patients with bacteremia caused by biofilm- and non-biofilm-forming isolates of A. baumannii, respectively, were enrolled. The clinical demographics, antimicrobial susceptibility, biofilm-forming ability, and patient clinical outcomes were analyzed. The biofilm-forming ability of the isolates was assessed using a microtiter plate assay. Multivariate analysis revealed the higher APACHE II score, shock status, lack of appropriate antimicrobial therapy, and carbapenem resistance of the infected strain were independent risk factors of 28-day mortality in the patients with A. baumannii bacteremia. However, there was no significant difference between the 28-day survival and non-survival groups, in terms of the biofilm forming ability. Compared to the patients infected with non-biofilm-forming isolates, those infected with biofilm-forming isolates had a lower in-hospital mortality rate. Patients with either congestive heart failure, underlying hematological malignancy, or chemotherapy recipients were more likely to become infected with the biofilm-forming isolates. Multivariate analysis showed congestive heart failure was an independent risk factor of infection with biofilm-forming isolates, while those with arterial lines tended to be infected with non-biofilm-forming isolates. There were no significant differences in the sources of infection between the biofilm-forming and non-biofilm-forming isolate groups. Carbapenem susceptibility was also similar between these groups. In conclusion, the patients infected with the biofilm-forming isolates of the A. baumannii exhibited different clinical features than those infected with non-biofilm-forming isolates. The biofilm-forming ability of A. baumannii may also influence the antibiotic susceptibility of its isolates. However, it was not an independent risk factor for a 28-day mortality in the patients with bacteremia.

Hospital-acquired infections in patients hospitalized with COVID-19: First report from Taiwan.

BACKGROUND: Coronavirus disease 2019 (COVID-19) inpatients may acquire infections from other pathogens during hospital admission. This is the first research on this subject to be reported from Taiwan. METHODS: Confirmed COVID-19 inpatients were enrolled in this study from January 1, 2020 to July 31, 2021. Various types of pathogens in COVID-19 inpatients, with hospital-acquired infections, were identified and analyzed. The clinical characteristics of COVID-19 patients with and without hospital-acquired infections were reviewed and compared. RESULTS: Of the 204 patients included in the study, 32 (15.7%) patients experienced at least one infectious episode. Of 113 recorded episodes of infection, the predominant type was bacterial (88 of 113 infections, 77.9%); the most frequently isolated bacteria were Acinetobacter spp., followed by Stenotrophomonas maltophilia . With regard to viral infections (19 of 113, 16.8%), the Epstein-Barr virus ranked first place among the identified viruses. Four (3.5%) and 2 (1.8%) of 113 infectious episodes were caused by fungi and atypical pathogens. A multivariate analysis revealed that steroid use was an independent factor in hospital-acquired infections (odds ratio [OR], 6.97; 95% confidence interval [CI], 1.15-42.43; p = 0.035). Patients with hospital-acquired infections were associated with increased 28-day and in-hospital mortality (18.8% vs 5.8% and 31.3% and 5.8%; p = 0.023 and <0.01, respectively), and a longer hospital stay (34 vs 19 days; p < 0.001), compared to those without hospital-acquired infections. CONCLUSION: Our study revealed the unique local epidemiology of hospital-acquired infections among COVID-19 inpatients in Taiwan. These patients were associated with increased mortality and prolonged hospital admissions.

Cancer as an infectious disease: A different treatment alternative using a combination of tigecycline and pyrvinium pamoate - An example of breast cancer.

BACKGROUND: Tigecycline is an antibiotic that well tolerated for treating complicated infections. It has received attention as an anti-cancer agent and expected to solve two major obstacles, sides effects that accompany chemotherapy and drug resistance, in the breast cancer treatment. However, previous studies reported that the levels in the blood are typically low of tigecycline, so higher doses are needed to treat cancer, that may increase the risk of side effects. To achieve better anti-cancer effects for tigecycline, we need to find a novel adjunct agent. METHODS: In this study, we used different concentration of pyrvinium pamoate combined with tigecycline to treat cell. And assess the effect of two drugs in inhibit cell proliferation, induce cell autophagy, or increase cell apoptosis to evaluate the consequent of combined therapy. RESULTS: We observed that after the combined therapy, the cell cycle arrest at G1/s phase, the level of p21 increased, but decreased the levels of CDK2. Others, two drugs via different mechanisms to inhibit cancer cell proliferation and with selective cytotoxic to different cell lines. That could enhance the effect of breast cancer treatment. CONCLUSION: Combining low dose of tigecycline use with pyrvinium pamoate is a novel approach for breast cancer treatment. Appropriate combined therapy in breast cancer is recommended to improve outcomes. Other problems like drug resistance occur in patients or the microbes surrounding breast tissues would confer susceptibility to cancers then influence the effectiveness of treatment, which could be improved through combined therapy.

Longitudinal non-cystic fibrosis trends of pulmonary Mycobacterium abscessus disease from 2010 to 2017: spread of the "globally successful clone" in Asia.

BACKGROUND: Mycobacterium abscessus (MAB) has emerged as the predominant pulmonary non-tuberculous mycobacterial pathogen in parts of Asia, including Taiwan. The reasons for the significant increase in MAB infections in the non-cystic fibrosis (CF) populations are poorly understood. The study aimed to elucidate whether this increase is related to the spread of the globally successful clone of MAB. METHODS: We performed multilocus sequence typing of 371 nonduplicated MAB pulmonary isolates from 371 patients sampled between 2010-2017 at seven hospitals across Taiwan. RESULTS: In total, 183 (49.3%) isolates were M. abscessus subsp. abscessus (MAB-a), 187 (50.4%) were M. abscessus subsp. massiliense (MAB-m), and 1 (0.3%) was M. abscessus subsp. bolletii (MAB-b). MAB-a sequence type (ST)1 (23.7%) and ST127 (3.8%), followed by MAB-m ST48 (16.2%), ST117 (15.1%), ST23 (8.6%) were most common overall. Of MAB-a strains, 50 (27.3%) belonged to novel STs and 38 (10.2%) were singleton strains, while of MAB-m strains, only 10 (5.3%) were novel and 8 (2.2%) were singletons. From 2010 to 2017, the frequency of the historically dominant ST1 declined from 28.6% to 22.5%, whereas the recently emerged globally successful clonal cluster 3, ST23 and ST48, increased from 14.3% to 40.0%. CONCLUSIONS: The dominance of ST1 particularly in the last 2 years of this study appears to be declining, while ST23, reported in outbreaks among CF and post-surgical cohorts across the Americas and Europe, alongside the closely related ST48, is present among non-CF populations in Taiwan. These trends need to be confirmed with further ongoing studies to track the molecular epidemiology of clinical MAB isolates worldwide.

Protective effect of N-acetylcysteine in prosthetic joint infection: A nationwide population-based cohort study.

PURPOSE: This nationwide population-based retrospective cohort study evaluated the protective effect of N-acetylcysteine against prosthetic joint infection after hip or knee joint replacement. METHODS: Patients receiving N-acetylcysteine after hip or knee joint replacement between 2000 and 2015 were identified from the Taiwan National Health Insurance Research Database. Each patient receiving N-acetylcysteine was matched to four controls based on age, sex, and index year. All subjects were followed-up from the index date to December 31, 2015. The Cox proportional hazards regression model was used to assess the risk of prosthetic joint infection. RESULTS: A total of 1478 patients were included in the study group, and 5912 matched subjects not receiving N-acetylcysteine were included in the control group. After adjusting for age, sex, insured premium, comorbidities, and immunosuppressive agent use, no significant difference in the risk of prosthetic joint infection was found between the two groups. A higher N-acetylcysteine dose (>360 cumulative defined daily dose) significantly decreased the risk of prosthetic joint infection (adjusted hazard ratio = 0.891; 95% confidence interval = 0.599-0.989; p = 0.042). The protective effect of N-acetylcysteine was observed only in the group of prosthetic joint infection within 5 years (adjusted hazard ratio = 0.801; 95% confidence interval = 0.581-0.980; p = 0.040). CONCLUSIONS: High cumulative dose of N-acetylcysteine (>360 cumulative defined daily dose) can effectively reduce the risk of prosthetic joint infection in patients undergoing knee or hip joint replacement surgery within 5 years.

Long-term results of posterior cruciate ligament tear with or without reconstruction: A nationwide, population-based cohort study.

BACKGROUND: There is increasing interest in the long-term outcomes of patients with posterior cruciate ligament (PCL) tears following conservative treatment or reconstruction. However, limited information is available regarding these results because of the relative rarity of cases and lack of long-term follow-up. PURPOSE: The goals of this study are to (1) compare the occurrence of secondary meniscal tears, osteoarthritis (OA) or subsequent total knee replacement (TKR) in patients with or without PCL injury, and (2) evaluate the potential protective effect of PCL reconstruction against long-term sequela in patients with PCL deficiency. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This retrospective cohort study evaluated the long-term results of PCL deficiency with or without reconstruction in Taiwan based on data from the National Health Insurance Research Database (NHIRD) from 2000 to 2015. The cumulative incidence rates of meniscus tear, OA and TKR were analyzed using the Kaplan-Meier estimator. Cox proportional hazards models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: A total of 4,169 patients diagnosed with PCL tear from 2000 to 2015 in Taiwan were included in the study. There was a higher cumulative incidence of meniscus tear (1.13%), OA (2.71%) and subsequent TKR (0.91%) among patients with a PCL tear than among patients without one (0.22%, 1.90%, 0.62%; all p < 0.05). PCL reconstruction patients had a decreased cumulative incidence of meniscus tear (0.41%), OA (2.30%) and subsequent TKR (0.48%) compared with non-reconstructed patients (2.44%, 3.46%, 1.69%; all p < 0.05). After adjusting for covariates, PCL-injured patients who underwent reconstruction within one year after PCL injury showed a significantly lower risk of subsequent sequelae than those who never underwent reconstruction (within 1 month: adjusted HR = 0.390, 95% CI = 0.284-0.535; 1 month to 1 year: adjusted HR = 0.546, 95% CI = 0.398-0.748). CONCLUSIONS: Patients with PCL tears have a significantly higher risk of meniscus tear, OA and subsequent TKR than patients without PCL tears. PCL reconstruction could decrease the cumulative incidence of these outcomes. The results suggest that PCL-injured patients should undergo reconstruction as early as possible (within one year) to reduce the risk of further degeneration.

Prevalence and Mortality-Related Factors of Multiple Myeloma in Taiwan.

In this retrospective cohort study based in Taiwan, we reported the current epidemiology of patients with multiple myeloma and analyzed the factors affecting mortality. We identified 7285 patients with newly diagnosed multiple myeloma (MM) between 1997 and 2013 in Taiwan. Privileges data from the National Health Institute Research Database was used, as it is made readily available to the public in electronic format for research purposes. From 1997 to 2013, the average incidence of MM per 100,000 people was 1.83. The mortality accounted for an average of 0.44 per 100,000 deaths. In all 7285 inpatients with MM, the proportion of male patients was greater than that of female (59.90% vs. 40.10%); the mean age was 68.71 years with the proportion of those >55 years of age was 85.11%; and the proportion of a catastrophic illness was 66.51%. The death risk of the inpatient dialysis group was 3.044 times that of patients without dialysis (P <0.001). Moreover, the risk of death to men in the hospital setting was 1.162 times that of women (P = 0.012), and in the group of patients aged >55 years, the risk of in-hospital death was 1.511 times more than that in those aged ≤55 years (P <0.001). The risk of hospital death due to catastrophic illness was 1.347 times that of a non-catastrophic illness (P <0.001). Male patients and those >55 years of age had the most common prevalence of MM in Taiwan. Hemodialysis treatment, male sex, old age, and catastrophic illness were independent predictors of hospital mortality in patients with MM.

In vitro activity of SecA inhibitors in combination with carbapenems against carbapenem-hydrolysing class D ß-lactamase-producing Acinetobacter baumannii.

OBJECTIVES: According to our previous study, OXA-58 translocates to the periplasm via the Sec pathway in carbapenem-resistant Acinetobacter baumannii (CRAb). In the present study, carbapenem-hydrolysing class D ß-lactamases (CHDLs) belonging to the OXA-23, OXA-40 and OXA-51 families were examined to determine whether they are also Sec-dependent. Additionally, the effects of SecA inhibitors combined with carbapenems against CHDL-producing CRAb were examined. METHODS: Cell fractionation and western blot analyses were performed to detect periplasmic His-tagged CHDLs. A chequerboard analysis with pairwise combinations of carbapenems (imipenem or meropenem) and SecA inhibitors (rose bengal, sodium azide or erythrosin B) was performed using six clinical CRAb isolates harbouring different CHDL genes. The fractional inhibitory concentration (FIC) index was determined. The combination with the lowest FIC index was subjected to a time-kill analysis to examine synergistic effects. RESULTS: In an in silico analysis, the CHDLs OXA-23, OXA-40 and OXA-51 were preferentially translocated via the Sec system. The SecA inhibitor rose bengal decreased periplasmic translocation of His-tagged OXA-23 and OXA-83 (belonging to the OXA-51 family), but not OXA-72 (belonging to the OXA-40 family) from ATCC 15151 transformants. Imipenem or meropenem with rose bengal showed synergistic effects (FIC index, ≤0.5) for six and four clinical isolates, respectively. Imipenem or meropenem with sodium azide showed no interactions (FIC index, 0.5-4) against all clinical isolates. Imipenem and rose bengal had the lowest FIC index and showed synergy at 24 h in the time-kill assay. CONCLUSIONS: Combinations of SecA inhibitors and carbapenems have synergistic effects against CHDL-producing CRAb.

Synthesis and Pharmacological Characterization of Novel Glucagon-like Peptide-2 (GLP-2) Analogues with Low Systemic Clearance.

Glucagon-like peptide-2 receptor agonists have therapeutic potential for the treatment of intestinal diseases. The native hGLP-2, a 33 amino acid gastrointestinal peptide, is not a suitable clinical candidate, due to its very short half-life in humans. In search of GLP-2 receptor agonists with better pharmacokinetic characteristics, a series of GLP-2 analogues containing Gly substitution at position 2, norleucine in position 10, and hydrophobic substitutions in positions 11 and/or 16 was designed and synthesized. In vitro receptor potency at the human GLP-2, selectivity vs the human GLP-1 and GCG receptors, and PK profile in rats were determined for the new analogues. A number of compounds more potent at the hGLP-2R than the native hormone, showing excellent receptor selectivity and very low systemic clearance (CL) were discovered. Analogues 69 ([Gly(2),Nle(10),D-Thi(11),Phe(16)]hGLP-2-(1-30)-NH2), 72 ([Gly(2),Nle(10),D-Phe(11),Leu(16)]hGLP-2-(1-33)-OH), 73 ([Gly(2),Nle(10),D-Phe(11),Leu(16)]hGLP-2-(1-33)-NH2), 81 ([Gly(2),Nle(10),D-Phe(11),Leu(16)]hGLP-2-(1-33)-NHEt), and 85 ([Gly(2),Nle(10),D-Phe(11),Leu(16)]hGLP-2-(1-33)-NH-((CH2)2O)4-(CH2)2-CONH2) displayed the desired profiles (EC50 (hGLP-2R) < 100 pM, CL in rat <0.3 mL/min/kg, selective vs hGLP-1R and hGCGR). Compound 73 (FE 203799) was selected as a candidate for clinical development.

A retrospective study of the incidence, clinical characteristics, identification, and antimicrobial susceptibility of bacteremic isolates of Acinetobacter ursingii.

BACKGROUND: Acinetobacter ursingii bacteremia is rarely reported. We investigated the incidence and clinical features of A. ursingii bacteremia, performance of the identification system, and antimicrobial susceptibility of the isolates. Acinetobacter ursingii bacteremia patients were compared with A. baumannii bacteremia patients. METHODS: In this 9-year retrospective study, A. ursingii was identified using 16S rRNA and 16S-23S rRNA internal transcribed spacer sequence analysis. The performances of the Vitek 2, Phoenix, and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometer systems for identifying isolates were tested. Pulsed-field gel electrophoresis (PFGE) was used to determine the clonality of the isolates. The minimal inhibitory concentrations of the antimicrobials were determined using the Vitek 2 system. RESULTS: Nineteen patients were identified. Acinetobacter ursingii was noted in 1.5-5.2 % of all Acinetobacter bacteremia cases. For the PFGE analysis, two isolates had smeared DNA, two had 93 % similarity, and 15 had similarity <80 %. Among 16 patients with complete medical records, 10 (62.5 %) had no identifiable source of A. ursingii bacteremia. Most patients (n = 12) had underlying malignant disease. Patients with A. ursingii bacteremia had lower Acute Physiology and Chronic Health Evaluation II scores than those with A. baumannii bacteremia (median [interquartile range], 17.1 [10.0-24.7] vs. 24.9 [14.6-35.1]). Patients with A. ursingii bacteremia were also less likely admitted to the intensive care unit than patients with A. baumannii bacteremia (18.8 % vs 63.5 %, p value < 0.01). About half of the patients with A. ursingii (50.8 %) and A. baumannii bacteremia (62.5 %) had received inappropriate antimicrobial therapy within 48 h after bacteremia onset. However, patients with A. ursingii bacteremia had significantly lower 14-day (6.25 % vs 29.8 %, p value = 0.04) and 28-day mortality rates (6.25 % vs 37.3 %, p value = 0.02) than patients with A. baumannii bacteremia. Nine isolates (47.4 %) were correctly identified as A. ursingii and the other 10 isolates (52.6 %) were incorrectly identified as A. lwoffii by the Vitek 2 system. The Phoenix system incorrectly identified all 19 isolates. The MALDI-TOF mass spectrometer system correctly identified all 19 isolates. All the A. ursingii isolates were resistant or showed intermediate susceptibility to ceftriaxone and ceftazidime, but were susceptible to levofloxacin and imipenem. CONCLUSIONS: Acinetobacter ursingii is a rare pathogen that mostly caused primary bacteremia in patients with malignancies. Patients with A. ursingii bacteremia had significantly lower disease severity and mortality rates than patients with A. baumannii bacteremia.

Risk factors and outcomes of cytomegalovirus viremia in cancer patients: a study from a medical center in northern Taiwan.

BACKGROUND: Cytomegalovirus (CMV) is a pathogen and can cause life-threatening infection in the patients with malignancies. This study was conducted to investigate the risk factors and outcomes of CMV viremia in patients with malignancies. METHODS: Data were collected with retrospective analysis from adults suffering from CMV viremia with underlying malignancies. A total of 107 patients were enrolled in a tertiary medical center in northern Taiwan from March 2008 to December 2009. RESULTS: Among the 107 patients who suffered with CMV viremia with an overall mortality rate of 56.1% (60/107), 75 patients (70.1%) had solid organ malignancies and 32 (29.9%) had hematological malignancies. Mechanical ventilation (p=0.048), leukocytosis (p=0.004), and lack of appropriate early treatment (p=0.011) were independent predisposing factors associated with higher mortality rate. CONCLUSIONS: CMV viremia predicts high mortality rate in cancer patients, especially in those with mechanical ventilation, leukocytosis, and lack of appropriate early treatment. Appropriate early antiviral therapy is recommended to improve outcomes.

Chryseobacterium indologenes peritonitis in a patient with malignant ascites.

Chryseobacterium indologenes is an uncommon pathogen of human disease and is usually associated with indwelling devices or immunocompromised hosts. We report here an unusual case of C. indologenes peritonitis in an oncological patient with malignant ascites. The patient was treated successfully by trimethoprim-sulfamethoxazole without removal of the catheter.

Lung cancer metastatic to the masticator space.

BACKGROUND: Distant metastasis from lung cancer occurs most frequently to the brain, bone, adrenal gland, liver, lymph nodes, and spinal cord. However, masticator space metastasis is rarely found among lung cancer patients. CASE REPORT: We report a case of large cell neuroendocrine carcinoma of the lung with metastasis to the masticator space diagnosed by imaging and histopathological examinations. CONCLUSION: The present case highlights the fact that large cell neuroendocrine carcinoma of the lung can result in an uncommon isolated masticator space metastasis. Clinicians should carefully evaluate cancer patients who report a painful sensation in the cheek. Thorough dental and physical examination, and imaging studies could provide early diagnosis and treatment.

Cytomegalovirus colitis mimics amebic colitis in a man with AIDS.

Opportunistic gastrointestinal infections are common in patients with HIV infection; both amebic colitis and cytomegalovirus (CMV) colitis are common causes of chronic diarrhea. It is difficult to distinguish these 2 diseases by nonspecific clinical symptoms such as diarrhea, abdominal pain, and weight loss. Here we report a case of CMV colitis mimicking amebic colitis with elevated indirect hemagglutination assay antibody titer against Entamoeba histolytica and negative IgM antibody titer against CMV. The diagnosis of CMV colitis was confirmed by eosinophilic nucleoli and inclusion bodies in colon biopsies. The patient recovered after ganciclovir and highly active antiretroviral therapy. Exact diagnoses are important for treating opportunistic infections. Other pathogens should be considered in patients with chronic diarrhea who are refractory to initial treatments. Our case highlights the importance of histopathological diagnosis for chronic diarrhea in patients with HIV infection and the possibility of false-positive results for indirect hemagglutination assay antibody against Entamoeba histolytica despite high titers.

Montelukast inhibits interleukin-5 mRNA expression and cysteinyl leukotriene production in ragweed and mite-stimulated peripheral blood mononuclear cells from patients with asthma.

Important in the pathogenesis of asthma is the secretion of interleukin (IL)-5 by allergen-specific TH2 cells, which augments eosinophil functions, as well as subsequent synthesis of cysteinyl leukotrienes (CysLTs). Montelukast is an inhibitor of CysLT and also has been shown to decrease eosinophil counts in peripheral blood and sputum of patients with asthma. This study was performed to investigate the in vitro effects of montelukast, a leukotriene receptor antagonist, on CysLTs and IL-5 production and expression by peripheral blood mononuclear cells (PBMCs) stimulated with ragweed (RW) and mite (M) allergens. In this study 18 patients with allergic asthma (nine women and nine men, aged 27-67 years) were evaluated. PBMCs from these patients were cultured for 24 hours in the presence of phytohemagglutinin (15 micrograms/mL), RW antigen E (0.39 U/mL), or M (16.8 micrograms/mL) allergens with (1, 10, 50 microM) and without montelukast. Enzyme-linked immunosorbent assay was used to measure the concentration of CysLTs, regulated upon activation, normal T-cell expressed and secreted (RANTES), and IL-5 in the culture supernatants and total RNA was extracted from the cultured PBMCs. Reverse transcription-polymerase chain reaction was performed on the RNA samples using beta-actin polymerase chain reaction primers for a control and IL-5 specific primers for detecting IL-5 mRNA expression in the cells. Elevated CysLT levels were noted in 8 of 18 patients with RW (range, 8-580 pg/mL) and in 13 of 18 patients with M (range, 7-1613 pg/mL). Inhibition of CysLTs by 10 microM of montelukast was noted in 5 patients with RW and in 10 patients with M. Levels of RANTES in some patients were increased by both allergens without consistent inhibitory effects of montelukast. IL-5 secretion measured by Enzyme-linked immunosorbent assay was detected in only 1 of 11 patients. However, in seven of nine patients tested, IL-5 mRNA was induced by both RW and M, and montelukast at 10 microM completely blocked IL-5 mRNA expression. Therefore, montelukast may be anti-inflammatory by inhibiting IL-5 mRNA expression and reducing CysLT secretion by PBMCs from asthmatic patients.