Simultaneous exposure to airborne flour particles and thermal load as cause of respiratory impairment

Summary In order to estimate whether only simultaneous exposure to both airborne flour particles and unfavorable thermal environment alone cause the development of nonspecific respiratory disease or whether sole exposure to flour aerosols is likely to cause impairment of the respiratory system, a group of 80 millers and 130 bakers, all nonsmokers, were examined. Both millers and bakers were exposed to approximately the same concentration of airborne flour particles but the latter worked under considerable thermal load. It was found that between millers and bakers the difference in the prevalence of respiratory symptoms was not statistically significant. Although the differences between the mean measured and the mean predicted ventilatory function parameters (FVC, FEV₁, PEF, MEF 50%, MEF 75%) were significant both in millers and bakers, they did not differ significantly between these two groups. This finding suggests that exposure to flour dust may cause the development of chronic nonspecific respiratory disease and a reduction of ventilatory lung capacity irrespective of simultaneous heat load.     

Increase in Memory (CD4+CD29+ and CD4+CD45RO+) T and Naive (CD4+CD45RA+)T-Cell Subpopulations in Smokers

To examine the effects of smoking on lymphocyte subpopulations, we measured the following cell subpopulations: CD4+ T-cell subpopulations (i.e., CD4+CD29+, CD4+ CD45RO+, and CD4+CD45RA+ cells); CD8+ T-cell subpopulations (i.e., CD8+CD11a+ and CD8+CD11b+ cells); and natural killer cell subpopulations (i.e., CD16+CD57-, CD16+CD57+, and CD16-CD57+ cells). We measured these subpopulations, together with total CD4+ T, total CD8+T, total CD3+T, B (CD19+), and total lymphocytes, in 10 male heavy smokers, 38 male light-to-moderate smokers, and 33 male nonsmokers. The mean ages were 30 y, 31 y, and 32 y, respectively, and ages did not vary significantly among the smokers. CD4+CD29+ and CD4+CD45RO+ (memory T) cells in heavy smokers were significantly more numerous than those in light-to-moderate smokers and nonsmokers. Also, these memory T-cell subpopulations were significantly more numerous in light-to-moderate smokers than in non-smokers. The number of CD4+CD45RA+ (naive T) cells was significantly larger in heavy smokers than nonsmokers; numbers of CD4+CD45RO+ T and CD4+CD29+ T cells (memory T cells) were significantly correlated with daily cigarette consumption. Numbers of CD3+ T, CD4+ T, CD19+ B, and total lymphocytes in heavy smokers were significantly larger than in nonsmokers. There were significantly more CD3+ T, CD4+ T, and total lymphocytes in light-to-moderate smokers than in nonsmokers. The numbers of CD4+ T lymphocytes in heavy smokers were significantly larger than in light-to-moderate smokers. Perhaps CD4+ T cell subpopulations, especially memory T cells, are most susceptible to the effects of smoking on lymphocyte sub-populations.     

Repeated high-intensity Wingate cycle bouts influence markers of lymphocyte migration but not apoptosis

Studies have shown significant changes in lymphocytes during continuous exercise, but little has been shown on the effect of repeated high intensity bouts. This study was designed to examine the effect of repeated intermittent bouts on lymphocyte subset cell count, apoptosis, and migration. A series of 6 Wingate anaerobic cycle tests were performed by participants (N = 8) with blood samples attained before, immediately following, and after a designated recovery period (excess postexercise oxygen consumption (EPOC)) to observe lymphocyte changes. Lymphocyte subsets (CD4+, CD4/CD45RA+, CD8+, CD8+/CD45RA+, CD19+) were assessed for apoptosis (annexin V+) and cellular migration (CX(3)CR1). Our results indicate that the CD8+ and CD8+/CD45RA+ subsets were significantly influenced by the repetitive Wingate cycling protocol such that cell counts increased with exercise, and then decreased at EPOC termination (p = 0.016). The observed postexercise decrease in CD8+ and CD8+/CD45RA+ cells was accompanied by a significant change in the CX(3)CR1 cell migration receptor (p = 0.019), but not apoptosis (p = 0.87). This indicates that with repetitive high-intensity cycling, the response in CD8+ cells following the bout is likely due to cell migration rather than cell death.     

Effects of smoking and Japanese cedar pollinosis on lymphocyte subpopulations

Approximately 10-30% of the Japanese population suffer from Japanese cedar (Cryptomeria japonica) pollinosis in the spring. To date, the effects of this pollinosis on lymphocyte subpopulations have not been examined epidemiologically. To examine the effects of smoking and Japanese cedar pollinosis on lymphocyte subpopulations, we used flow cytometry to measure CD4+ and CD8+ T-lymphocyte subpopulations, natural-killer cell subpopulations, B(CD19+) lymphocytes, and total lymphocytes in 61 smokers and 51 nonsmokers. Some of these individuals had histories of pollinosis during November 1993-an off-season for Japanese cedar pollination. Our findings suggested that (a) CD4+ T-lymphocyte subpopulations (i.e., CD4+CD29+, CD4+CD45RA+, and CD4+ CD45RO+ cells) together with total CD4+ T, total T, and total lymphocytes, were increased by the effects of smoking; (b) CD8dim+CD11a+T, and CD8+CD11bt, and CD57+CD16+ natural killer cells, together with total CD8+CD11 a+ T and total CD8+ T lymphocytes, were increased by the effects of pollinosis on smokers, even though no lymphocyte subpopulations were increased by only the pollinosis effects; (c) CD4+CD29+T and CD8dimCD11a+ T lymphocytes were increased by the effects of smoking on pollinosis, and (d) CD4+CD29+ T and CD4+CD45RO+ T lymphocytes, CD8dim+CD11 a+ T, and CD8+CD11b+ T lymphocytes and CD57+CD16+ natural killer cells, together with total CD4+ T, total T (CD3+), total CD8+CD11a+, total CD8+ T, and total lymphocytes, were increased by the combined effects of smoking and pollinosis.     

Distribution of naïve (CD45RA+) and memory (CD45RO+) T-cells in HIV-infected Puerto Rican population

HIV infection usually results in a gradual deterioration of the immune system. It is evident that early recognition of progression markers during HIV infection from asymptomatic to symptomatic state is needed. In the present cross-sectional study, peripheral blood lymphocytes from 63 HIV-infected Puerto Rican individuals were analyzed by two-color flow cytometry to study the co-expression CD45RA and CD45RO on both CD4+ and CD8+ T-cells and its correlation with age, gender, CD4 count, CD4:CD8 ratio, anti-retroviral therapy, clinical status, and viral load. Measurement of T-cell subsets in these patients showed an excessive increase of CD3+CD8+, CD8+CD45RA+, and CD8+CD45RO+ T-cells as disease progresses. In contrast, it was also observed a significant decrease in CD3+CD4+, CD4+CD45RA+ and CD4+CD45RO+ T-cells. The distribution of CD8+CD45RA+ T-cells did not change significantly between HIV and AIDS cases suggesting that this T-cell subset is not a good progression marker. Interestingly, CD4+CD45RA+ T-cells were significantly difference between genders, and CD44+CD45RA+ and CD8+CD45RO+ T-cells were influenced by age. In conclusion, the distribution of na?ve/memory CD4+ T-cells and memory CD8+ T-cells significantly correlate with HIV infection in disease progression. It is also important to mention that these T-cell subpopulations may be influenced by both gender and age. Overall, these results suggest that a loss in the generation of new immune response and function may be occurring during disease progression. This study open new windows of understanding that will be beneficial for future studies on immunopathogenesis, diagnosis, prognosis, and treatment monitoring for HIV/AIDS.     

低水平长期铅接触对作业工人淋巴细胞亚群的影响

[目的]检测淋巴细胞亚群以探讨低水平长期铅接触对免疫系统的影响。[方法]对44名铅作业工人和34名对照者采用流式细胞仪进行淋巴亚群分型及用酶联免疫法检测IgE,检测项目包括：CD3、CD4、CD8、CD45RO、CD19、HLADR、IgE。[结果]CD4^ CD45RO^ 、CD3^-HLADR^ 淋巴细胞铅接触组明显低于对照组,CD19^ 、CD4^ CD45RO^-、CD3^ HLADR^ 淋巴细胞和IgE两组间没有显著性差异。[结论]长期低水平铅接触可能影响T淋巴细胞亚群,从而影响细胞免疫功能。     

铬盐职业接触对T细胞部分免疫功能的影响

目的 了解铬盐对职业接触者体内免疫指标变化的影响.方法 115名不同浓度铬盐接触工人为接触组,以远离铬盐污染区的90名居民为对照组.采用原子吸收分光光度法测定研究对象作业环境铬盐浓度;采用荧光标记流式细胞分析法测定研究对象外周血中T细胞CD3~+、CD3~+CD4~+、CD3~+CD8~+及CD4~+/CD8~+水平.结果 接触组空气中铬盐个体环境暴露浓度为(27.51±33.25)μg/m~3,对照组浓度为(0.16±0.15)μg/m~3,两组比较差异有统计学意义(z=8.045,P<0.01).铬盐接触组人群CD3~+、CD3~+CD4~+、CD3~+CD8~+及CD4~+/CD8~+平均水平分别为:(30.08±17.75)%、(1.04±1.73)%、(11.94±9.78)%、0.10±0.14;对照组为:(63.00±13.57)%、(30.51±5.16)%、(14.82±4.59)%、2.17±0.53.两组比较,对照组高于接触组,差异有统计学意义(z值分别为:4.484、5.227、1.976、-5.218,P值均<0.05).结论在铬盐个体环境暴露评价基础上,铬盐接触者以T细胞为主的细胞免疫功能受到抑制,而CD3~+CD4~+有望作为铬盐接触免疫损伤的早期效应性生物标志物,值得进行更深入研究.     

Increase in CD57 + CD16 - lymphocytes in workers exposed to benzidine and beta-naphthylamine: assessment of natural killer cell subpopulations

Previously, we found a decrease in CD4+CD45RA+T lymphocytes in workers exposed to the aromatic amines (AAs) [benzidine (BZ) and beta naphthylamine (BNA)]. For further investigation of the effects of AAs on lymphocyte subpopulations, we measured natural killer (NK) cell subpopulations using two-color staining with anti-Leu7 (CD57) and anti-Leu11 (CD16) monoclonal antibodies in peripheral blood in 78 male dyestuff workers. The workers had been exposed to AAs before 1972 at a chemical plant, either in the production of AAs (40 workers, high-exposure group) or in other work that involved handling dye-stuffs (38 workers, low-exposure group). The controls were 30 “healthy” male volunteers without a history of occupational exposure to AAs or hazardous chemicals. The number of CD57+CD16-cells in the high-exposure group was significantly higher than that in the controls (P<0.01, analysis of covariance with age as a covariate). No significant differences were found in CD57+CD16-, CD57+CD16+ and CD57-CD16+NK cells between the low-exposure group and the controls. It is suggested that a decrease in the number of CD4+ T lymphocytes following exposure to AAs might be compensated by the increase in CD57+CD16- cells, i.e. circulating peripheral lymphocytes with poor NK cell activity.     

Effects of occupational metallic mercury vapour exposure on suppressor-inducer (CD4+CD45RA+) T lymphocytes and CD57+CD16+ natural killer cells

Objectives: To examine the effects of metallic mercury vapour on the cellular and humoral immune system. Methods: We measured T lymphocyte and natural killer (NK) cell subpopulations, B lymphocytes, and serum immunoglobulins (i.e. IgG, IgA and IgM) together with total T (CD3+) lymphocytes and total lymphocytes in blood samples from 20 male, fluorescent-lamp makers (mercury workers) and the same number of gender-, age- and smoking-matched controls. Urinary concentrations of inorganic mercury (UHg) in the 20 workers ranged from 1.8 to 163.5 (mean 44.8) μg/l. They had been exposed to mercury vapour for 4 to 62 (mean 31) months. Results: Numbers of CD4+CD45RA+ (suppressor-inducer) T lymphocytes and total CD4+ T lymphocytes in the mercury workers were significantly smaller than those in the controls (paired-sample t-test, P < 0.01). The number of CD57+CD16+ NK cells was inversely correlated with UHg. Conclusion: It is suggested that numbers of CD4+CD45RA+ T lymphocytes and CD57+CD16+ NK cells are inversely affected by exposure to metallic mercury vapour in workers, with an average urinary inorganic mercury concentration of 45 μg/l being found. Received: 7 September 1999 / Accepted: 6 May 2000     

Decreases in CD8+ T, naive (CD4+CD45RA+) T, and B (CD19+) lymphocytes by exposure to manganese fume

To examine the effects of exposure to manganese (Mn) on the cellular and humoral immune system in men, T lymphocyte subpopulations, B (CD19+) lymphocytes, natural killer (NK) cells, and serum immunoglobulins (i.e., IgG, IgA and IgM) together with total T (CD3+) lymphocytes and total lymphocytes were measured in blood samples from 21 welders mainly exposed to Mn fume with blood Mn (BMn) concentrations of 0.6-2.3 (mean 1.4) microg/dl and 21 healthy controls working in the same factory (BMn concentrations: 0.7 to 1.7, mean 1.1 microg/dl). The workers engaged in welding for 6 to 36 (mean 17) yr. All the study subjects were divided into 3 equally sized groups (n=14 for each group) according to BMn concentrations. Numbers of CD8+ T, total T (CD3+), B (CD19+), and total lymphocytes were significantly lower in high-BMn group than those in low-BMn group; the numbers of CD8+ T lymphocytes were significantly lower in moderate-BMn group compared to low-BMn group. After adjusting for age and smoking, significant inverse correlations between BMn concentrations and CD4+CD45RA+ T, CD4+ T, CD8+ T, CD3+ T, and total lymphocytes were found. We conclude that T lymphocytes, especially CD8+ and CD4+CD45RA+ T lymphocytes, as well as CD19+ B lymphocytes are affected by exposure to Mn fume.     

Decreases of natural killer cells and T-lymphocyte subpopulations and increases of B lymphocytes following a 5-day occupational exposure to mixed organic solvents.

The authors examined the effects of organic solvents on lymphocyte subpopulations in blood. Natural killer and T-lymphocyte subpopulations and B (CD19+) -lymphocytes were measured with flow cytometry in 16 male rotogravure printers on a Friday and on the following Monday. Numbers of all 3 subpopulations of natural killer cells (i.e., CD57+ CD16+, CD57- CD16+, and CD57+ CD16- cells), 2 subpopulations of T lymphocytes (CD4+ CD45RA+ and total CD8+ cells), and total lymphocytes on Friday were significantly fewer than those found on the following Monday. Conversely, the number of B lymphocytes on Friday was significantly larger than the number on Monday. The number of B lymphocytes was significantly correlated with blood toluene levels on Friday. The alteration in the number of CD57+ CD16+ NK cells from Friday to the following Monday was correlated inversely with the corresponding change in exposure level of toluene on Friday. The authors suggest that the effects of mixed organic solvents (primarily toluene) are recoverable decreases of natural killer cells and T lymphocytes and increases in B lymphocytes.     

Immunologic findings among lead-exposed workers

A comprehensive panel of immune parameters was evaluated among 145 lead-exposed workers with a median blood lead level (BLL) of 39 μg/dL (range: 15–55 μg/dL) and 84 unexposed workers. After adjusting for covariates, we found no major differences in the percentage of CD3+ cells, CD4+ T cells, CD8+ T cells, B cells, or NK cells between lead-exposed and unexposed workers, although the association between lead exposure and the number of CD4+ T cells was modified by age. We also found no differences between exposed and unexposed workers in serum immunoglobulin levels, salivary IgA, C3 complement levels, or lymphoproliferative responses. However, among exposed workers, the percentage and number of B cells were positively associated with current BLL, serum IgG was negatively associated with cumulative lead exposure, and the percentage and number of CD4+/CD45RA+ cells were positively associated with cumulative lead exposure. We found no evidence of a marked immunotoxic effect of lead at the exposure levels studied, although some subtle differences in immunologic parameters were noted. Am. J. Ind. Med. 33:400–408, 1998. Published 1998 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

微波辐射对作业人员外周血T淋巴细胞亚群的影响

目的探索长期低剂量高功率微波辐射对作业人员免疫功能的影响。方法对38名某研究所雷达科研人员(接触组)和39名非微波作业人员(对照组)进行外周血白细胞计数和淋巴细胞百分率,以及T淋巴细胞亚群CD3+、CD4+、CD8+和CD4+/CD8+比值的测定。结果与对照组相比,接触组白细胞计数和淋巴细胞百分比均降低,但差异不显著:接触组CD3+、CD4+、CD8+均升高,CD4+/CD8+比值降低,差异显著;接触组≤10 a组的T淋巴细胞亚群的变化差异不显著,接触组>10 a组CD3+、CD4+、CD8+及CD4+/CD8+比值均升高,且CD3+升高差异显著。接触组和对照组组内工龄≤10 a和>10 a间T淋巴细胞亚群的差异不显著。结论长期低剂量高功率微波辐射能明显导致人体免疫功能紊乱,但未表现出累积效应。应当采取有效的职业防护。     

Changes in natural killer cell subpopulations in lead workers

To investigate the effects of lead on human immune system, we analyzed T cell subpopulations (CD4+, CD8+ and CD3+ cells), natural killer (NK) cell subpopulations (CD16+ and CD57+ cells) and B (CD19+) cells in peripheral blood in 29 male lead workers. All were engaged in manufacturing lead stearate in a chemical factory. They were aged 23–74 (mean 49) years. Their blood lead concentrations (PbB) were between 7 and 35 (mean 18) μg/dl. They were divided into two groups according to their PbB: a high-PbB group (?20?μg/dl), and a low-PbB group (<20?μg/dl). The control group consisted of 19 “healthy” male workers without a history of occupational exposure to lead or to other hazardous substances, aged 48–67 (mean 58) years. The number and percentage of CD16+ cells in the high-PbB group were significantly lower than those in the controls and in the low-PbB group. There was significant negative correlation between the number of CD16+ cells and PbB in the lead workers. The percentage of CD8+ cells in the high-PbB group was larger than that in the controls and in the low-PbB group. It is suggested that the CD16+ NK cell should be a major site of the effects of lead on lymphocyte subpopulations.     

锌缺乏对生长期大鼠外周血淋巴细胞表型及亚群分布的影响

目的 :　观察膳食锌缺乏对生长期大鼠外周血淋巴细胞表型及 Th1 /Th2 (Th,辅助 T细胞 )平衡的影响。方法 :　通过喂食锌含量不同的饲料 ,构建生长期缺锌大鼠模型 ;淋巴细胞表型检测采用双色免疫荧光流式细胞术分析。结果 :　与锌充足组 (ZA)和配饲组 (PF)相比 ,缺锌组(ZD)大鼠外周血淋巴细胞中 CD8+细胞 (细胞毒性 T细胞 )明显增多 ,而 CD4+细胞 (辅助 T细胞 )和 CD45 RA+细胞 (纯的 B淋巴细胞 )显著减少。而且锌缺乏选择性地使 Th1 (CD45 RC+CD4+)细胞减少 ,而 Th2 (CD45 RC- CD4+)细胞不减少。补锌后上述改变可得到恢复。结论 :　膳食锌缺乏导致淋巴细胞表型分布改变和 Th1 /Th2的平衡破坏 ,但这些改变是可逆性的     

Decreases of Natural Killer Cells and T-Lymphocyte Subpopulations and Increases of B Lymphocytes Following a 5-Day Occupational Exposure to Mixed Organic Solvents

The authors examined the effects of organic solvents on lymphocyte subpopulations in blood. Natural killer and T-lymphocyte subpopulations and B (CD19+) -lymphocytes were measured with flow cytometry in 16 male rotogravure printers on a Friday and on the following Monday. Numbers of all 3 subpopulations of natural killer cells (i.e., CD57+ CD16+, CD57-CD16+ and CD57+CD16- cells), 2 subpopulations of T lymphocytes (CD4+ CD45RA+ and total CD8+ cells) and total lymphocytes on Friday were significantly fewer than those found on the following Monday. Conversely, the number of B lymphocytes on Friday was significantly larger than the number on Monday. The number of B lymphocytes was significantly correlated with blood toluene levels on Friday. The alteration in the number of CD57+CD16+ NK cells from Friday to the following Monday was correlated inversely with the corresponding change in exposure level of toluene on Friday. The authors suggest that the effects of mixed organic solvents (primarily toluene) are recoverable decreases of natural killer cells and T lymphocytes and increases in B lymphocytes.     

乳腺癌患者外周血T细胞亚群与NK、NKT细胞检测的临床意义

目的:检测乳腺癌患者外周血T淋巴细胞亚群及NK、NKT细胞表达率的变化,探讨乳腺癌患者免疫状况与肿瘤分期的关系以及免疫指标变化在治疗前后的临床价值。方法 :采用荧光标记法与多参数流式细胞仪检测40例正常女性和120例乳腺癌患者的总T淋巴细胞(CD3+)、T辅助/T诱导细胞(CD3+CD4+)、T抑制/细胞毒细胞(CD3+CD8+)、自然杀伤细胞(NK)、NK样T细胞(NKT)的表达率,并进行统计学分析。结果:无淋巴结转移组乳腺癌患者治疗前CD3+、CD3+CD4、CD3+CD8+、CD4+/CD8+与对照组比较无统计学意义,NK、NKT显著低于对照组(P<0.05)。淋巴结转移组乳腺癌患者CD3+、CD3+CD4、CD3+CD8+、NK、NKT表达率均明显低于对照组(P<0.05)。经过综合治疗后乳腺癌组各项免疫指标均恢复到正常值。结论:外周血T细胞亚群的检测对判断乳腺癌患者的病情、临床分期有一定意义;经过治疗后能够有效地改善乳腺癌患者的免疫状态。     

Decrease of suppressor-inducer (CD4+ CD45RA) T lymphocytes and increase of serum immunoglobulin G due to perceived job stress in Japanese nuclear electric power plant workers

To clarify the effects of perceived job stress on the immune system, a cross-sectional study was conducted in 116 male Japanese workers of a nuclear electric power plant (age, 20 to 39; mean, 31 years). Perceived job stress, i.e., psychological job demand, job control, worksite social support, and job strain, was assessed by means of the Japanese version of the Job Content Questionnaire. The job strain score was calculated as the ratio of the job demand score to the job control score. Blood samples were taken from all workers, and numbers of T and natural killer cell subpopulations, B lymphocytes, total lymphocytes and white blood cells, and serum concentrations of immunoglobulins (IgG, IgM, IgA, IgE and IgD) in their blood were measured. The workers were divided into higher and lower strain groups according to their job strain scores. The number of CD4+ CD45RA+ T lymphocytes in the higher strain group having the job strain score of 0.5 or more (41 workers) was significantly smaller than that in the lower strain group having the score of less than 0.5 (75 workers). In contrast, the serum IgG concentration in the former group was significantly higher than that in the latter group (analysis of covariance with age and smoking as covariates). Also, the numbers of total CD4+ T and total T (CD3+) lymphocytes and of white blood cells in the former group were significantly smaller than those in the latter group. After controlling for age and smoking by the partial correlation coefficient in all 116 workers, the number of CD57+ CD16+ natural killer cells was inversely correlated with job demand and with job strain; the number of CD8+ T lymphocytes was positively correlated with worksite social support; and serum IgG and IgM concentrations were positively correlated with job strain. It is suggested that higher job strain decreases the number of CD4+ CD45RA+ T lymphocytes in male Japanese workers but increases serum IgG concentrations.     

特发性血小板减少性紫癜患者外周血淋巴细胞亚群和血小板特异性抗体检测的临床意义

目的 检测特发性血小板减少性紫癜(ITP)患者外周血淋巴细胞亚群、血小板膜糖蛋白(GPⅡb/Ⅲa、GPⅠb/Ⅸ)特异性抗体变化,探讨相关因素在ITP发病机制中的作用.方法 用流式细胞术检测72例ITP患者(ITP组)和50例健康体检者(对照组)外周血淋巴细胞亚群CD3+、CD4+、CD8+、CD4+/CD8+、CD19+变化.应用改良血小板抗原单克隆抗体固相化检测技术测定GPⅡb/Ⅲa、GPⅠb/Ⅸ特异性抗体变化.结果 ITP组与对照组比较,GPⅡb/Ⅲa、GP Ⅰ b/Ⅸ特异性抗体吸光度值升高(P＜0.05),CD3+、CD4+、CD4+/CD8+显著下降(P＜0.01),CD8+、CD19+显著增高(P＜0.01).结论 淋巴细胞亚群及血小板特异性抗体可较好地反映ITP的病理机制,在ITP的发病机制中起非常重要的作用.     

Occupational benzene exposure from vehicular sources in India and its effect on hematology, lymphocyte subsets and platelet P-selectin expression

Benzene exposure from vehicular sources and its health impact are relatively unexplored in India. We have investigated in this study hematology and lymphocyte subsets of 25 petrol pump attendants, 25 automobile service station workers and 35 controls matched for age, sex and socioeconomic conditions. The participants were non-smoking males of Kolkata (former Calcutta) in eastern India. Compared with controls, the workers had 3.8- times more trans,trans-muconic acid in urine, suggesting higher level of benzene exposure. The exposed subjects had decreased erythrocyte, hemoglobin, lymphocyte and platelet levels, but increased neutrophil, band cells, RBC aniso-poikilocytosis and target cells. In addition, CD4+, CD8+ and CD19+ cells were decreased by 37, 20 and 47% respectively, but CD 16+ 56+ NK cells were increased by 20%. P-selectin expression on platelet surface of the workers was significantly elevated (P < 0.05), indicating upregulation of platelet activity. In summary, the study revealed high level of benzene exposure from vehicular sources in India, and the exposed subjects had hematological and immunological alterations.