Aspergillus fumigatus diffusates suppress polymorphonuclear neutrophil phagocytic functions and respiratory burst levels in hematopoietic stem cell transplantation patients

Invasive aspergillosis (IA) is a severe infection that commonly occurs in immunocompromised patients after hematopoietic stem cell transplantation (HSCT). The present study explores the effect of Aspergillus fumigatus diffusates (AfDs) on phagocytic function and superoxide anion (O2(-)) burst levels in polymorphonuclear neutrophils (PMNs) from post-HSCT patients. A. fumigatus conidia with or without AfD were used to stimulate the PMN from healthy donor or HSCT patient for two hours. PMN morphology was visualized by scanning electron microscopy. The levels of respiratory burst O2(-) produced by the PMNs were determined by flow cytometry. PMN phagocytic rates and phagocytic indexes were observed and calculated using periodic acid-Schiff (PAS) staining under a light-field microscope. No difference was found between the PMN phagocytic rates, phagocytic indexes, or O2(-) respiratory burst levels in health donor PMNs following treatments of A. fumigatus conidia with or without AfD. However, significant inhibition of these indices was seen in the PMNs from HSCT patients following treatment of A. fumigatus conidia plus AfD, compared to that with conidium treatment alone (P < 0.05). Therefore, AfD significantly inhibited the phagocytic function of PMNs from HSCT patients, potentially through inhibition of intracellular respiratory burst levels during phagocytosis. This suggests that the reason underlying the greater susceptibility of HSCT patients to aspergillosis might be the existence of AfD in vivo during infection. Further research on the mechanisms by which AfD affects the phagocytic function of PMNs from HSCT patients is therefore of great significance for the prevention of IA.

Toll-like receptor 2 agonist Pam3CSK4 up-regulates FcεRI receptor expression on monocytes from patients with severe extrinsic atopic dermatitis

BACKGROUND

Both microbial antigens and allergens are important factors that can trigger atopic dermatitis (AD). Monocytes from patients with AD have been found to express increased and sustained levels of high-affinity IgE receptor (FcεRI) and Toll-like receptor 2 (TLR2). We hypothesized that putative interactions exist between TLR2 and FcεRI on monocytes in the pathogenesis of AD.

OBJECTIVE

This study aimed to understand whether activation of TLR2 by Pam3CSK4 would influence the expression of FcεRI, and whether mitogen-activated protein kinase (MAPK) signalling pathways were involved in such regulation.

METHODS

Peripheral blood monocytes from patients with severe extrinsic AD or healthy control patients were treated with the TLR2 agonist Pam3CSK4. The expression of FcεRI, intracellular TNF-α and MAPK family members were analysed by real-time quantitative PCR, flow cytometry and western blotting.

RESULTS

Monocytes from patients with severe extrinsic AD expressed higher levels of surface FcεRIα than were found in monocytes from healthy controls. Stimulation of human monocytes from patients with Pam3CSK4, but not lipopolysaccharide (LPS), resulted in the up-regulation of surface FcεRI expression by inducing p38 phosphorylation. Pretreatment with a specific inhibitor of p38 kinase inhibited the Pam3CSK4-induced up-regulation of FcεRIα, suggesting the involvement of the p38 pathway in the regulation of this process.

CONCLUSION

Our findings indicated interactions between TLR2 and FcεRI occurred via the activation of p38 in patients with severe extrinsic AD, which might indicate insights into understanding the mechanisms of how bacterial infection can exacerbate the clinical features of AD.

Increased circulating follicular helper T cells and activated B cells correlate with disease severity in patients with psoriasis

BACKGROUND

Follicular Helper T (TFH) Cells are a population of recently discovered CD4(+) T cells involved in autoimmune diseases. However, the contribution of TFH cells in patients with psoriasis remains unknown.

OBJECTIVE

We aimed to investigate the levels of TFH cells, B cells and their clinical relevance in patients with psoriasis.

METHODS

Using multi-colour flow cytometry, we detected different subsets of TFH cells and B cells in the peripheral blood of 27 patients with psoriasis and 13 healthy donors. Serum IL-21 levels were measured by ELISA. The relationship between the levels of TFH cells, IL-21, B cells and disease severity were analysed.

RESULTS

Compared with healthy donors, higher levels of circulating CD3(+) CD4(+) CXCR5(+) cells, CD3(+) CD4(+) CXCR5(+) ICOS(+), CD3(+) CD4(+) CXCR5(+) PD-1(+), CD3(+) CD4(+) CXCR5(+) ICOS(+) PD-1(+) TFH cells and CD19(+) IgD(+) CD27(-) naive B, CD19(+) CD86(+) activated B, but lower levels of CD19(+) IgD(+) CD27(+) preswitch and CD19(+) IgD(-) CD27(+) postswitch memory B cells, were observed in patients with psoriasis. In addition, serum IL-21 levels in patients with psoriasis were significantly higher than those in healthy donors, and showed to be positively correlated with the levels of different subsets of TFH cells, and the level of CD19(+) CD86(+) B cells was also correlated with TFH cells and IL-21 levels. Furthermore, a significant correlation was found between the levels of CD3(+) CD4(+) CXCR5(+) ICOS(+) TFH cells, CD3(+) CD4(+) CXCR5(+) ICOS(+) PD-1(+) TFH cells, CD19(+) CD86(+) B cells and IL-21 with Psoriasis Area and Severity Index scores.

CONCLUSION

The levels of TFH cells and activated B cells were increased in the peripheral blood of patients with psoriasis, and positively correlated with disease severity. These results suggest that TFH cells and activated B cells may play a role in the pathogenesis of psoriasis.

Association of PELI1 polymorphisms in systemic lupus erythematosus susceptibility in a Chinese population

Objective

Studies in animal models have indicated that Pellino 1 is involved in inflammatory and autoimmune diseases, such as systemic lupus erythematosus (SLE). The current study was designed to determine whether PELI1 confers genetic susceptibility to SLE in humans, as assessed in a Chinese Han population.

Methods

Blood samples were drawn from patients diagnosed with SLE and healthy volunteers. Three single nucleotide polymorphism (SNP) loci with a minor allele frequency of at least 0.05 were chosen to evaluate the correlation between PELI1 genotype and the incidence of SLE.

Results

There was a significant difference in the frequency distribution of the rs329497 allele between the SLE patients and the healthy controls (A vs. G; Bonferroni corrected p = 0.036, odds ratio = 0.75, 95% confidence interval = 0.60–0.94). No differences in the genotype and allele frequencies of other SNP loci were observed between the two groups. Furthermore, the alleles and genotypes of the three SNPs were not associated with lupus nephritis.

Conclusion

In the Chinese Han population, PELI1 SNPs may be associated with SLE susceptibility.

Dendritic cell vaccine treatment of advanced de novo colorectal cancer in renal transplant patients

Objective: The clinical outcome, especial the immunologic responses to cancer and graft, of dendritic cell (DC) vaccine in the treatment of advanced de novo colorectal cancer (CRC) in renal transplant patients was investigated in this study. Materials and Methods: 7 patients were received 1 cycle tumor lysate pulsed autologous DC vaccine. The positive cell-mediated cytotoxicity responses to DC vaccine against CRC cell in two out of 7 patients were seen by delayed type hypersensitivity (DTH) test. The positive cell-mediated cytotoxicity responses to DC vaccine against normal kidney cell in all 7 patients were not seen by DTH tests and no notable change of renal function during and after vaccination. Conclusions: DC vaccine has emerged as a promising new strategy in the treatment of advanced de novo CRC in renal transplant patients and DC vaccines have become an attractive therapeutic option, developing immune responses specific against CRC cell, achieving clinical efficacy without graft failure.

Immunological changes after ASIT in AD allergen-specific immunotherapy and their potential correlation with clinical response in patients with atopic dermatitis patients sensitized to house dust mite

BACKGROUND

Allergen-specific immunotherapy (ASIT) is the main treatment for inducing long-term immunological and clinical tolerance in patients with IgE-mediated allergic diseases. Recent open-label and controlled studies on the efficacy of ASIT in patients with atopic dermatitis (AD) have provided promising results. However, data about possible relationship between the improvement of clinical symptoms and changes of serum cytokines are limited.

METHODS

Seventy-nine patients with moderate to severe AD sensitized to house dust mite (HDM) were enrolled. Fifty-eight patients were treated with ASIT and 11 controls received only symptomatic treatment. The disease activity in AD patients was evaluated by using the patient-oriented eczema measure (POEM) system. Serum interleukin (IL)-4, IL-10, interferon (IFN)-γ, transforming growth factor (TGF) β1, total IgE, HDM-specific IgE (s-IgE) and HDM-specific IgG4 (s-IgG4) were measured before and after 2 years of therapy.

RESULTS

The mean patient-oriented eczema measure system (POEM) score of AD patients with ASIT significantly decreased after 2 years of treatment, compared to that in patients without ASIT. After ASIT, the serum levels of IL-10, TGF-β1, IFN-γ and s-IgG4 increased, while the level of IL-4 decreased. The change in the POEM score was negatively correlated with changes of serum concentration of TGF-β1, s-IgG4 and IFN-γ. Furthermore, s-IgG4 levels were positively correlated with changes in the IL-10 levels. No correlation between POEM score and serum IL-10 or IL-4 was observed.

CONCLUSION

Clinical symptoms and the quality of life of AD with HDM sensitization could be improved after 2 years of ASIT. Changes in serum IL-10, TGF-β1, s-IgG4 and IFN-γ might be considered as biomarkers to assist clinical evaluation of the therapeutic effects of ASIT in patients with AD.

Chronic urticaria in Chinese population: a hospital-based multicenter epidemiological study

BACKGROUND

The epidemiologic profiles of chronic urticaria (CU) vary considerably among regions, and few such data are available from China.

METHODS

We performed a multicenter open questionnaire investigation about the clinical and laboratory features of CU, defined as recurrent wheals with/without angioedema lasting for ≥6 weeks, among 3027 patients.

RESULTS

Female preponderance was observed (female/male ratio, 1.46 : 1). The mean age at diagnosis was 34.7 ± 13.8 years, and the mean disease duration was 18.5 ± 46.1 months (range, 1.5-127 months). Patients were classified as having chronic spontaneous urticaria (CSU, 61.0% of patients), physical urticaria (PU, 26.2%), or other urticaria types (OU, 2.3%). Nocturnal attacks were reported by 60% of cases. The Urticaria Activity Score (UAS) in patients with CSU was 3.8 ± 1.4. The mean Dermatology Life Quality Index was 7.3 ± 3.4 (range 0-30). Induction or exacerbation of wheals with alcohol drinking was reported by 55.7% of patients. Chronic hepatitis B was less prevalent in our CU patients compared with the general Chinese population (2.7% vs 7%). Positive autologous serum skin tests (ASSTs) were observed in 66.9% of patients. Patients with positive ASST had higher UAS, greater angioedema frequencies, longer disease durations, and poorer QoL compared with patients with negative ASST (P < 0.05).

CONCLUSION

In this Chinese population, CU usually affected youth, and CSU was the most common subtype. Autoreactivity and alcohol consumption were the top two triggers for CU, whereas latent infectious and chronic inflammatory diseases were not as common as in previous reports.

The association between trauma and melanoma in the Chinese population: a retrospective study

BACKGROUND

The association between trauma and melanoma has been a controversial issue.

OBJECTIVES

To analyse the profiles of melanoma, and to determine whether trauma is associated with development of acral melanoma in the Chinese population.

PATIENTS AND METHODS

Retrospective analysis of 685 cases of cutaneous melanoma in the dermatology departments of Xijing Hospital in northwestern China and Xinan Hospital in southwestern China from 1982 to 2011.

RESULTS

Of the 685 patients included in the study, 437 (63.8%) suffered from melanoma on the extremities. A total of 104 patients (15.2%) exhibited an association between trauma and melanoma. The primary anatomic sites of the tumours were the upper extremities (17, 16.3%), lower extremities (74, 71.2%) and other sites (13, 12.5%). Among these cases, the extremities were with remarkably higher risks of post-trauma melanoma than the other sites [adjusted odds ratio (OR) 3.968; 95% confidence interval (CI) 2.267-5.592]. Notably, patients in the south part of China were with a stronger risk of post-trauma melanoma on the lower extremities than those in the north (adjusted OR 1.764; 95% CI 1.192-2.666) part. In addition, a significant higher risk of post-trauma melanoma on the extremities was observed in the male gender (adjusted OR 1.848; 95% CI 1.186-2.887).

CONCLUSIONS

Our findings provide epidemiological evidence for a potential association between traumatic events and melanoma of the extremities, especially the lower limbs, where a history of trauma is more likely.

An effect comparison between Furlow double opposing Z-plasty and two-flap palatoplasty on velopharyngeal closure

The aim of this study was to compare velopharyngeal closure between patients who underwent Furlow palatoplasty and two-flap palatoplasty. A retrospective review of 88 patients with incomplete palate cleft was performed. 48 patients (17 males; 31 females) aged 2-28 years received Furlow palatoplasty. 40 patients (17 males; 23 females) aged 2-21 years received two-flap palatoplasty. Velopharyngeal function was categorized as adequate, marginal or inadequate. Complications associated with the operation were documented. Statistically significant differences were not found amongst sex distribution, age at operation, follow-up time, and preoperative speech intelligibility. After primary repairs using Furlow and two-flap palatoplasty, the surgeon's incidence of postoperative palatal fistula was 0%. The complications were not significantly different between the two groups. The authors achieved the lowest reported incidence of postoperative palatal fistulas in primary Furlow palatoplasty. The outcomes of the velopharyngeal closure were better in patients who received Furlow palatoplasty (P<0.05). Furlow palatoplasty was more effective than two-flap palatoplasty in obtaining perfect velopharyngeal closure. A probable explanation may be that Furlow palatoplasty can reposition and overlap the divergent palatal muscle and lengthen the soft palate.

Intron-1 rs3761548 is related to the defective transcription of Foxp3 in psoriasis through abrogating E47/c-Myb binding

Foxp3 is a master transcription factor (TF) for development and function of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg cells) and is critical for the transcription of target genes. But the transcriptional regulation of Foxp3 itself has not been fully understood until now. Here, we aimed to demonstrate the hypothesis that upstream single nucleotide polymorphism(s) (SNPs) of Foxp3 was/were responsible for the defective transcription of Foxp3 in psoriasis and to explore the mechanism behind this hypothesis. In this study, SNP of large sample was investigated for risk analysis. Mature algorithms, electrophoretic mobility shift and chromatin immunoprecipitation assays were used to identify TF binding site variations. Loss-of-function and overexpression assays and cell cycle blocker assay were performed to identify when and what kind of possible roles the candidate factors play. Our results showed that intron-1 rs3761548 was correlated with a significant susceptibility to psoriasis. The rs3761548 contributed to the decreased resting Foxp3 transcription and impaired acceleration of Foxp3 transcription levels after stimulation in psoriatic patients with genotype AA. We analysed and demonstrated potent new E47/c-Myb -dependent regulation elements in rs3761548, oppositely controlling Foxp3 gene transcription at G1 and G2/M phases of Treg cells in psoriatic patients. For patients with rs3761548 AA, the polymorphism causes loss of bindings to the E47 and c-Myb factors, leading to defective transcription of Foxp3 gene. Further identification of the networks and molecular mechanisms underlying Foxp3 transcription may provide new insights into Foxp3 transcriptional regulation and alternative therapeutic strategies to improve characteristics of autoimmune disorders.

Investigation of optimal aminolaevulinic acid concentration applied in topical aminolaevulinic acid-photodynamic therapy for treatment of moderate to severe acne: a pilot study in Chinese subjects

BACKGROUND

Aminolaevulinic acid-photodynamic therapy (ALA-PDT) is a novel and effective treatment in acne. However, little is known about the effect of different concentrations of ALA in the treatment of acne in Chinese patients with Fitzpatrick skin type III and IV.

OBJECTIVES

To investigate the efficacy and safety of ALA-PDT in the treatment of moderate to severe acne in Chinese patients and to identify the suitable concentration of topical ALA.

METHODS

One hundred and eighty patients with moderate to severe facial acne were recruited and randomly divided into four groups. Each group was treated with a different concentration (5%, 10%, 15% and 20%) of ALA to the facial lesions on the right side and placebo agent on the left side as control. Each patient was treated once every 10 days for four sessions. The numbers of inflammatory and noninflammatory acne lesions were counted at baseline and at weeks 2, 4, 12 and 24 after the last treatment. Adverse effects were recorded at each follow-up visit.

RESULTS

After 24 weeks, each side treated by ALA-PDT showed clinical improvement compared with the control side treated by red light alone (P < 0·01). Statistically significantly more patients treated with 20% ALA than with 15% or 10% ALA achieved complete clearance. Regarding side-effects, a trend towards more serious erythema and pigmentation was observed with increasing ALA concentration.

CONCLUSIONS

Increasing the concentration of ALA seems to be beneficial for improving the results. Considering effectiveness and safety, ALA-PDT using 10% or 15% ALA is suggested to the ideal treatment for moderate to severe acne in Chinese patients with Fitzpatrick skin type III and IV.

Association of TBX21 gene haplotypes in a Chinese population with systemic lupus erythematosus

OBJECTIVE

T-cell-specific T-box transcription factor (T-bet) is a member of the T-box family of transcription factors regulating type 1 T-helper (Th1) cell development and is thought to be linked with several autoimmune diseases including systemic lupus erythematosus (SLE). The aim of this study was to evaluate whether T-bet gene (TBX21) polymorphisms or its haplotypes are associated with SLE in a Chinese population.

METHODS

The study included 248 cases with SLE and 261 gender- and age-matched healthy controls. The polymorphisms T-1993C (rs4794067) and T-1514C (rs17250932) in the TBX21 promoter were identified by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay.

RESULTS

The frequency of both the -1993T and the -1514T allele were significantly higher in SLE patients than in controls. By haplotype analysis, there was significantly decreased frequency of the haplotype at positions -1993C/-1514C in the case group compared with the control group (p = 0.0002). Multifactorial logistic regression analysis showed that individuals with CC/CC haplotype homozygotes had a decreased susceptibility to SLE [p = 0.0004, odds ratio (OR) 0.316, 95% confidence interval (CI) 0.167-0.599].

CONCLUSION

Our results suggest that the -1993C/-1514C haplotype may be a protective factor for genetic susceptibility to SLE in the Chinese population.

Skin colonization by Staphylococcus aureus in patients with eczema and atopic dermatitis and relevant combined topical therapy: a double-blind multicentre randomized controlled trial

BACKGROUND

Staphylococcus aureus has a peculiar ability to colonize the skin of patients with eczema and atopic dermatitis (AD), and is consistently found in eczematous skin lesions in these patients. A correlation between the severity of the eczema and colonization with S. aureus has been demonstrated, and it has been determined that bacterial colonization is an important factor aggravating skin lesions. Patients colonized with S. aureus have been treated with antibiotics in several open and double-blind placebo-controlled studies, with conflicting results.

OBJECTIVES

To investigate the colonizing features of S. aureus in the lesional and nonlesional skin of patients with eczema and AD in China and to compare the therapeutic effect of mupirocin plus hydrocortisone butyrate with vehicle ointment plus hydrocortisone butyrate.

METHODS

A multicentre, double-blind randomized trial was conducted. Eczema Area and Severity Index (EASI) scores were evaluated before the start of the trial and on the 7th, 14th and 28th day of treatment. Swabs for bacterial isolation were taken from lesional skin before the start of the trial and on the 7th, 14th and 28th day of treatment, and from nonlesional skin only before the start of the trial. A combination topical therapy with mupirocin plus hydrocortisone butyrate ointment was used in the experimental group, with vehicle ointment plus hydrocortisone butyrate ointment as a control.

RESULTS

Of 327 patients enrolled in the study, 208 had eczema and 119 had AD. Bacteria were isolated from 70.2% of lesional and 32.7% of nonlesional skin samples from patients with eczema, of which S. aureus accounted for 47.3% and 27.9%, respectively. Bacteria were isolated from 74.8% of lesional and 34.5% of nonlesional skin samples from patients with AD, of which S. aureus accounted for 79.8% and 80.5%, respectively. The colonization density of S. aureus was markedly higher in lesional than in nonlesional skin, both in patients with eczema and with AD (P < 0.01, P < 0.05), and was positively correlated with lesion severity. Considering the EASI scores before and after treatment and the final effective rate, good therapeutic effects were obtained in both the combination experimental groups and the control groups (P < 0.01), and there were no differences in the global therapeutic effect between the two groups in patients with eczema and with AD (P > 0.05). However, in patients with eczema with a clinical score of > 8 or in patients with AD with a clinical score of > 7, the therapeutic effect in the experimental groups was superior to that in the control groups (P < 0.05) on the 7th day of treatment. There were no differences between the two groups on the 14th and 28th days of treatment (P > 0.05). Following the improvement of symptoms and signs of eczema and AD, the positive rates of bacteria and S. aureus were reduced on the 7th day of treatment.

CONCLUSIONS

This study confirmed that lesional skin of patients with eczema and AD was more frequently colonized with S. aureus than was nonlesional skin. The more severe the eczema, the higher the colonization rate of S. aureus, and S. aureus was also more often present in lesional and nonlesional skin in patients with AD than in those with eczema. Staphylococcus aureus infection is related to the pathogenesis of eczema and AD. An antibiotic-corticosteroid combination and corticosteroid alone both gave good therapeutic effect in eczema and in AD, and both reduced colonization by S. aureus. Early combined topical therapy is beneficial to patients with moderate to severe eczema and AD, and it is unnecessary to use antibiotics at later stages of disease or in mild eczema or AD.

[Production and identification of the monoclonal antibodies specific for MHC class I complexes bound with HPV16E7 CTL epitopic peptide.]

BACKGROUND

To produce specific monoclonal-antibodies (MAbs) for MHC class I complexes bound with HPV16E7 CTL epitopic peptide (49-57), and provide a foundation for the investigation of the present pathway of viral antigen protein after in vitro viral infection.

METHODS

Highly purified HPV16E7CTL epitope (49-57) (RAHYNIVTF) was produced, and then TAP deficient RMA-S cells incubated with RAHYNIVTF were used to immunize the BALB/c mouse. The spleen cells of the mice were regularly harvested and fused with the SP2/0 cells. The growing fusion wells were screened and the abstracted Mabs were identified in terms of sensitivity, specificity and affinity.

RESULTS

The screened hybriroma cells could steadily secrete the MAbs specific for MHC class I complexes bound with HPV16E7CTL epitopic peptide. The MAbs showed high reactivity with TAP-deficient RMA-S cells loaded with RAHYNIVTF and RMA-S cells which have the ability to process the endogenous MHC class I complexes, while minimally bound to class I molecules bearing other peptides, the results indicated excellent sensitivity, specificity and affinity of the MAbs.

CONCLUSION

The experiments provide a method for producing MAbs for epitopic peptide bound MHC class I complexes.

Gene profiling involved in immature CD4+ T lymphocyte responsible for systemic lupus erythematosus

We attempted to characterize the genes expression of CD4+ T lymphocytes for the pathogenesis of systemic lupus erythematosus (SLE). Genomewide gene expression profiles of CD4+ T cells, which were isolated from the disease severe activity (T4-1s) and nonactivity (T4-2s) with an SLE patient by using long serial analysis of gene expression (LongSAGE). We picked out 289 genes matching to Unigene cluster with different expression more than four copies between T4-1s and T4-2s libraries and analyzed their roles from the collectedly published articles of PubMed by genes functional clustering. The genes functions were related to a diverse cellular process including: (1) most of these genes were associated with CD4+ T cells functions, particularly related to cellular developments; (2) Ras pathway genes as RANBP10, GMIP, RASGRP2 and ARL5 might be responsible for the abnormal development of CD4+ T cells of SLE; (3) HIG2, TCF7, KHSRP, WWP1, SMAD3, TLK2, AES, CCNI and PIM2 belong to Wnt/beta-catenin way, they could play roles in modulating proliferation and differentiation of T lymphocytes; (4) uncertain viral infections may initiate autoimmunity because high levels expression genes were detected in T4-1s such as TRIM22, IER2, ABCE1, DUT, G1P2, G1P3, HNRPUL1, EVER2, IFNAR1, TNFSF14, TMP21 and PVRL2; and (5) apoptosis relating genes as EIF3S8, SH3BGRL3, GPX4, TOSO, PFDN5, BIN1, XIAPAF1, TEGT and CUGBP2 may contribute to over uploading of selfantigens in SLE cells. Abnormalities findings of multiple genes expression involving with a variety of CD4+ T cells process might be meaningful to understanding the pathogenesis of SLE, and immature CD4+ T cells may be responsible for SLE.

Determination of aliphatic amines in mineral flotation liquors and reagents by high-performance liquid chromatography after derivatization with 4-chloro-7-nitrobenzofurazan

The method described here fulfils the need for a suitable analytical method to determine the concentrations of single and mixed aliphatic amines in the range from hexylamine (C6) to octadecylamine (C18) in flotation test solutions and in commercial flotation collectors. Amines do not have a UV-vis spectrum in aqueous solution but by reacting an amine-containing solution with 4-chloro-7-nitrobenzofurazan solution (chloro-NBD), derivatized products (amino-NBDs) are formed which have absorbance maxima at 470nm. Excess chloro-NBD and the amino-NBDs can be separated from each other by high-performance liquid chromatography (HPLC) and their concentrations measured with a UV-vis detector. Important variables in the derivatization stage are pH, temperature, chloro-NBD concentration, and reaction time, all of which interact with each other. A three-stage statistical procedure was used to determine the optimum conditions. In each stage, an 8-test design was used in which a high and low limit was set for each variable, and the chromatogram peak area of the derived amino-NBD was measured. The optimum derivatization conditions established were pH 8.9, chloro-NBD concentration 0.20% (w/v), temperature 70 degrees C, and reaction time 60 min. Optimum elution conditions for chromatography were an eluent containing 80% (v/v) acetonitrile in aqueous solution containing 40mM acetic acid at pH 4.5. With a flow rate of 2.0 ml/min, dodecylamine had a retention time of about 3 min, whereas octadecylamine had a retention time of 44 min. Straight-line calibration curves were obtained up to at least 200 ppm of amine in solution. The lower limit of detection was estimated to be 0.05 microM (10ppb) with a signal to noise ratio of 3. No interfering substances were found. The method was successfully applied to the analysis of solutions from an actual flotation test and to a solid commercial amine.