腺苷脱氨酶检测对结核性脑膜炎诊断的临床价值

目的评价脑脊液中腺苷脱氨酶(ADA)检测对结核性脑膜炎诊断的应用价值。方法采用酶显色法检测102例4组病例(结核性脑膜炎组30例,化脓性脑膜炎组34例,病毒性脑膜炎组15例,头痛症状组23例)脑脊液中ADA的活性水平。结果30例结核性脑膜炎组脑脊液中ADA活性明显增高,ADA6.0U/L26例,与化脓性脑膜炎组比较差异有统计学意义(P0.01),敏感性为86.7%(26/30),特异性为91.7%(66/72)。化脓性脑膜炎组和病毒性脑膜炎组与头痛症状组(对照组)比较差异也具有统计学意义(P0.05)。结论检测脑脊液中ADA的活性对于结核性脑膜炎诊断和鉴别诊断有重要的临床价值。     

脑脊液腺苷脱氨酶测定对结核性脑膜炎的诊断意义

目的探讨脑脊液腺昔脱氨酶(ADA)活性测定对结核性脑膜炎诊断的临床意义。方法对确诊的50例结核性脑膜炎、46例病毒性脑膜炎、42例化脓性脑膜炎及40例非脑炎患者采用LX20全自动生化分析仪检测脑脊液ADA活性。结果结核性脑膜炎患者组脑脊液ADA活性明显高于其它非结核性脑膜炎患者,平均为(12.69±5.08)U/L,最高达27.33U/L。病毒性脑膜炎、化脓性脑膜炎和其它非脑膜炎患者脑脊液ADA分别为(3.26±1.03)U/L(、4.52±2.11)U/L、(2.99±1.22)U/L,最高9.04U/L,与结核性脑膜炎患者相比差别有统计学意义(P<0.01)。结核性脑膜炎组43例患者治疗6周后脑脊液中ADA活性比刚入院时明显降低,差别有统计学意义(P<0.01)。结论脑脊液腺苷脱氨酶可作为诊断结核性脑膜炎的重要参考指标。     

Cerebrospinal fluid C-reactive protein in infective meningitis in childhood

The value of cerebrospinal fluid C-reactive protein (CSF CRP) determination as a diagnostic aid in infective meningitis has been investigated in four groups of children. In a "no meningitis" group of 10 children, a median CSF CRP value of 0.08 micrograms/ml was obtained (range 0 to 0.31 micrograms/ml); in a viral meningitis group of 21 children a median value of 0.01 micrograms/ml (range 0 to 3.06 micrograms/ml); in a bacterial meningitis group of 27 children a median value of 9.6 micrograms/ml (range 0 to 31.5 micrograms/ml); and in a tuberculous meningitis group of 18 children a median value of 0.29 micrograms/ml (range 0 to 4.9 micrograms/ml). CSF CRP values in the bacterial meningitis group differed significantly from those of each of the other groups (P less than 0.01), but considerable overlap between the groups detracted from the diagnostic value of the test. In six patients with bacterial meningitis with ambiguous conventional CSF chemistry results, normal CSF CRP values were found. Simultaneous serum CRP was determined in nine patients with tuberculous meningitis and 11 with bacterial meningitis, and the CRP response in both the serum and CSF appears subdued in tuberculous meningitis in comparison with bacterial meningitis. CSF CRP and total protein values were determined intermittently during a 24-hour period in ventricular CSF from two children with tuberculous meningitis who underwent temporary direct ventricular drainage. A considerable and apparently parallel diurnal variation in both values was seen. CSF CRP values have limited application in the etiologic diagnosis of meningitis.     

结核性脑膜炎患者脑脊液中腺苷脱氨酶的动态观察

目的　动态观察结核性脑膜炎患者脑脊液中腺苷脱氨酶的变化 ,以期对结核性脑膜炎的早期诊断和预后判断提供依据。方法　采用比色法动态检测 4 3例结核性脑膜炎患者脑脊液中腺苷脱氨酶活力的变化 ,并以 2 2例病毒性脑膜炎患者作为对照组。结果　 4 3例结核性脑膜炎患者酶活性较对照组明显升高 ,差异有统计学意义 (P <0 .0 5 ) ,治疗后 2周内结核性脑膜炎患者腺苷脱氨酶活力较其他时间明显增高 ,此后腺苷脱氨酶活力随治疗时间的延长呈进行性下降趋势。另外 8例有不同程度的神经系统并发症结核性脑膜炎患者呈现持续高水平。结论　检测脑脊液中腺苷脱氨酶是早期诊断结核性脑膜炎的一个简单而可靠的方法 ;动态观察腺苷脱氨酶还能对疾病的预后判断提供依据。     

Recent survey of infectious meningitis in adults: review of laboratory findings in bacterial, tuberculous, and aseptic meningitis.

Infectious meningitis in adults was reviewed to establish the frequency of meningitis due to each causative agent and to reexamine the laboratory parameters that help to distinguish aseptic, bacterial, and mycobacterial meningitis. Aseptic meningitis occurred 2.2 times more often than bacterial and mycobacterial meningitis combined. The most common nonviral causative agent was the pneumococcus (23 cases) followed by the tubercle bacillus (11 cases) and the meningococcus (5 cases). Cerebrospinal fluid (CSF) Gram stain was the most useful study to rule in a bacterial cause: 89% of cases of bacterial meningitis had a positive initial Gram stain. Hyponatremia occurred in 73% of cases of tuberculous meningitis; hyponatremia combined with a negative Gram stain was highly suggestive of a tuberculous cause. One third of all patients with tuberculous and aseptic meningitis had a predominance of neutrophils in the CSF. No patient with aseptic meningitis had a CSF while count higher than 2,800 cells/cu mm or a CSF protein value higher than 250 mg/100 ml. Other reviews confirm this if cases due to lymphocytic choriomeningitis (LCM) are excluded. One patient with tuberculous meningitis in this series, and none of those cases reviewed, had a CSF white count higher than 1,200 cells/cu mm. Only 3.7% of the patients with aseptic meningitis had hypoglycorrhachia. Series reporting exclusively disease due to mumps and LCM have a higher frequency of hypoglycorrhachia.     

Diagnostic value of lactate dehydrogenase isoenzymes in cerebrospinal fluid

To evaluate the diagnostic value of lactate dehydrogenase (LD) isoenzymes in cerebrospinal fluid (CSF), 93 consecutive CSF specimens were analyzed. These specimens were from patients of four categories: tumors, infections, hemorrhages, and others. It was found that the isoenzyme patterns overlapped among different categories, but they differed within each category and were thus helpful in differential diagnosis. For instance, metastatic tumors showed prominent LD-5, whereas a primary brain tumor demonstrated an increase in all fractions. Viral encephalitis revealed an increase in the first three isoenzymes and bacterial meningitis, the last two. In acquired immune deficiency syndrome (AIDS) cases, however, LD isoenzyme changes were demonstrated in CSF when only cryptococcal meningitis and not when encephalitis was present. Both subdural and subarachnoid hemorrhages showed elevation of all fractions in our study. Elevation of the first three fractions was usually due to brain tissue damage or hemorrhage, as proven by our isoenzyme study of hemolysate mixed with CSF. The prominence of the last two fractions was related to anaerobic metabolism in the central nervous system or to granulocytic infiltration. In conclusion, LD isoenzyme analysis in CSF is helpful in differential diagnosis of various CNS disorders, although its sensitivity awaits further improvement.     

T细胞斑点试验在结核性脑膜炎诊断中的应用价值

目的分析结核感染T细胞斑点试验(T-SPOT.TB)在结核性脑膜炎诊断中的应用价值。方法以2017年1月-2019年12月安徽省胸科医院收治的93例脑膜炎患者为研究对象,其中确诊或临床诊断为结核性脑膜炎62例,非结核性脑膜炎31例。所有入组患者治疗前均检测外周血T-SPOT.TB,脑脊液腺苷脱氨酶(ADA)、结核分枝杆菌DNA(TBDNA)、抗酸杆菌(AFB)涂片,对试验结果进行分析。结果外周血T-SPOT.TB检测诊断结核性脑膜炎的灵敏度为82.3%(51/62),特异度为80.7%(25/31),灵敏度明显高于脑脊液ADA(61.3%,38/62)、脑脊液TB-DNA(27.4%,17/62)、脑脊液AFB涂片(16.1%,10/62),差异均有显著统计学意义(P<0.01)。采用受试者工作特征(ROC)曲线及其曲线下面积(AUC)来分析不同试验方法的诊断价值,外周血T-SPOT.TB、脑脊液ADA、脑脊液TB-DNA和脑脊液AFB涂片的AUC值分别为0.815、0.661、0.637、0.581。外周血T-SPOT.TB在结核性脑膜炎中的诊断效能最高。结论外周血T-SPOT.TB在结核性脑膜炎的诊断中,可作为可靠的辅助参考指标之一。     

腺苷脱氨酶同工酶在结核性胸积液和肿瘤性胸积液的诊断价值研究

目的探讨腺苷脱氨酶（ADA）同工酶（ADA1和ADA2）活性检测在结核性胸积液和肿瘤性胸积液的鉴别诊断意义。方法收集36例结核性胸积液和28例肿瘤性胸积液为研究对象,检测结核性胸积液和肿瘸性胸积液的总ADA和ADA2活性,比较两组胸积液的总ADA和ADA2活性区别在鉴别诊断的意义。结果结核性胸积液组的总ADA、ADA2活性显著高于肿瘤性胸积液组（P〈0．01）。在诊断结核性胸膜炎上,总ADA的敏感性和特异性分别为83．3％和92．86％;ADA2的敏感性和特异性分别为83．3％和96．4％。在诊断肿瘤性胸膜炎上,总ADA的敏感性和特异性分别为92．8％和81．2％,ADA2的敏感性和特异性分别为96．4％和81．8％。结论检测胸积液总ADA和ADA2活性可为结核性胸积液和肿瘤性胸积液的鉴别诊断提供有效参考,检测ADA2活性优于总ADA活性。     

三种脑部炎症病变脑脊液铁蛋白、脑脊液白蛋白/血清白蛋白比值和免疫球蛋白的变化及意义

目的　探讨结核性脑膜炎、病毒性脑膜炎、急性播散性脑脊髓炎脊液铁蛋白、脑脊液白蛋白 /血清白蛋白比值及脊液免疫球蛋白的变化及诊断意义。方法　检测结核性脑膜炎 31例、病毒性脑膜炎 32例、急性播散性脑脊髓炎 30例患者的脑脊液铁蛋白、脑脊液白蛋白 /血清白蛋白比值及脊液免疫球蛋白的变化 ,并与 30例正常者作对照。结果　方差分析显示结核性脑膜炎、病毒性脑膜炎、急性播散性脑脊髓炎及对照组脑脊液铁蛋白、脑脊液白蛋白 /血清白蛋白比值差异均有统计学意义 (P <0 .0 0 0 1) ,3组脑部疾病间的铁蛋白、脑脊液白蛋白 /血清白蛋白比值差异均有统计学意义 (P均 <0 .0 5 )。方差分析结核性脑膜炎、病毒性脑膜炎及急性播散性脑脊髓炎脑脊液IgA、IgM、IgG变化差异有统计学意义 (P <0 .0 0 0 1) ,结核性脑膜炎组脑脊液IgA、IgM较急性播散性脑脊髓炎及病毒性脑膜炎显著升高(P <0 .0 5 ) ,急性播散性脑脊髓炎IgG较结核性脑膜炎及病毒性脑膜炎显著升高 (P <0 .0 5 )。结论　结核性脑膜炎、病毒性脑膜炎、急性播散性脑脊髓炎脊液铁蛋白、脑脊液白蛋白 /血清白蛋白比值和脊液免疫球蛋白的变化和差异 ,可作为诊断和鉴别诊断的参考指标。     

Serum adenosine deaminase: isoenzymes and diagnostic application.

Human adenosine deaminase (ADA; EC 3.5.4.4) consists of three isoenzymes: ADA1, ADA1+CP, and ADA2. We developed an electrophoretic technique to distinguish between these three isoenzymes. The isoenzyme pattern was studied in tissue and cell homogenates, as well as in serum from normal subjects and from patients with increased serum ADA who had either hepatitis, infectious mononucleosis, tuberculosis, pneumonia, rheumatoid arthritis, or acute lymphoblastic leukemia (ALL). The highest ADA activity was found in lymphocytes and monocytes. ADA2 could be detected only in monocytes (18% of total ADA activity). It was also the predominant isoenzyme in the sera of controls and all disease groups, except for ALL--the only condition evaluated that is not of an inflammatory nature. We conclude that serum ADA reflects monocyte/macrophage activity or turnover in most diseases studied. The exception is ALL, where serum ADA most probably originates from lymphocyte precursors.     

结核性脑膜炎患者脑脊液基质金属蛋白酶-9及其抑制剂检测

目的:探讨结核性脑膜炎患者脑脊液中基质金属蛋白酶-9(MMP-9)和基质金属蛋白酶组织抑制剂1(TIMP-1)水平的变化意义。方法:选取5例非肿瘤非感染性头痛患者脑脊液作对照,9例病毒性脑膜炎,12例结核性脑膜炎患者。12例结核性脑膜炎根据有无意识障碍或脑实质损害的症状分为两组,A组有意识障碍或脑实质损害症状,7例;B组无意识障碍或脑实质损害症状,5例。酶联免疫吸附测定(ELISA)方法检测脑脊液MMP-9和TIMP-1水平。结果:结核性脑膜炎脑脊液MMP-9的水平及MMP-9/TIMP-1比例显著增高,A组增高得更显著。结论:脑脊液MMP-9水平及MMP-9/TIMP-1比例对结核性脑膜炎的诊断和预后有参考价值。     

结核性脑膜炎抗结核菌纯蛋白衍生物抗体与脑脊液细胞学的相关性

目的 探讨结核性脑膜炎(结脑)患者不同阶段抗结核菌纯蛋白衍生物(PPD)抗体阳性率及脑脊液细胞学变化,推测二者之间是否有相关性及其诊断价值。方法 结脑患者26例,病毒性脑膜炎（病脑）患者30例,在发病1、2、3、4周分别测其脑脊液抗PPD抗体IgG及脑脊液细胞学结果。结果 结脑组在发病早期1周内,抗PPD抗体IgG阳性率低,脑脊液细胞学浆细胞出现率低;发病2~3周,抗PPD抗体IgG阳性率升高,浆细胞出现比例升高;发病4周,经有效治疗后,抗PPD抗体IgG阳性率仍高,浆细胞比例降低或消失。病脑组在发病第1、2、3、4周脑脊液抗PPD抗体IgG阴性,脑脊液细胞学以淋巴细胞反应为主,浆细胞出现率低。结论 结脑患者抗PPD抗体IgG阳性率低,浆细胞比例低或无;抗PPD抗体IgG阳性率高,浆细胞比例高,二者有相关性;二者结合可提高早期结脑诊断率。     

Informative value of adenosine deaminase and 2-deoxyadenosine deaminase in the diagnosis of tuberculous pleurisy

Adenosine deaminase (ADA) and 2-deoxyadenosine deaminase (2-deoxyADA) activities were measured in pleural exudation of different origin in 373 patients (124 of these with serous tuberculous pleurisy and 75 with specific empyema). High diagnostic value of ADA activity in the presence of threshold value higher than 35 Units/liter was established: the sensitivity of the test in the diagnosis of tuberculous pleurisy and empyema was 94.4 and 93.3% respectively, specificity 93.0 and 89.5%, respectively. Judging by the coefficient of 2-deoxyADA/ADA, total ADA activity is determined by the activity of ADA-2 isoenzyme, while in tuberculous empyema by ADA-1. Additional use of this coefficient, requiring measurement of 2-deoxyADA activity, does not improve the efficiency of the diagnostic process, including measurement of total ADA activity in pleural exudate.     

Cerebrospinal fluid/blood glucose ratio as an indicator for bacterial meningitis

Background

Bacterial meningitis is an emergent disease requiring prompt diagnosis and treatment with appropriate antimicrobials. Although the lumbar puncture is widely used as a diagnostic tool for bacterial meningitis, it remains unclear which value in cerebrospinal fluid (CSF) analysis in emergency laboratory tests precisely predicts the presence of bacterial meningitis.

Methods

This is a single-center, retrospective review of medical records to determine which emergency laboratory CSF test results are useful for predicting bacterial meningitis. The diagnosis of meningitis is made when the white blood cell count in CSF exceeds 5 cells/μL, while the diagnosis of bacterial meningitis additionally requires the growth of a pathogen from a CSF culture or the identification of a pathogen in Gram staining of CSF specimen.

Results

We identified 15 patients with bacterial meningitis and 129 patients with aseptic meningitis. While neutrophil-predominant pleocytosis and a decreased glucose level in CSF can predict the presence of bacterial meningitis, the CSF/blood glucose ratio is more precise (optimal cut-off = 0.36, sensitivity = 92.9%, specificity = 92.9%, area under the curve = .97) even after administration of antimicrobials prior to examination in the emergency department.

Conclusion

This study suggests that the CSF/blood glucose ratio may be a better single indicator for bacterial meningitis. Since the CSF glucose and blood glucose values are promptly and easily obtained from a lumbar puncture, the CSF/blood glucose ratio should be considered as a timely diagnostic indicator of bacterial meningitis. It may also help exclude the diagnosis of bacterial meningitis especially in cases in which no microorganisms can be cultured.     

Adenosine deaminase activity in the serum and malignant tumors of breast cancer: the assessment of isoenzyme ADA1 and ADA2 activities

OBJECTIVE: The potential relationship between adenosine deaminase activity and cancer progression was examined by investigating the activity of total ADA and its isoenzymes in serum and simultaneously in the cancerous tissue of each patient with breast cancer. METHODS: Total ADA and its isoenzymes were measured using the Giusti method. ADA2 activity was measured in the presence of a specific ADA1 inhibitor, EHNA. RESULTS: Our results indicated that ADA2 and total ADA activities were higher in serum and malignant tissues than those of corresponding controls (P < 0.05). Tumor ADA2 and total ADA activities were significantly (P < 0.05) correlated with lymph node involvement, histological grade and tumor size, whereas their levels in serum were significantly (P < 0.05) correlated with menopausal status and patient age. CONCLUSION: Although serum and tumor total ADA activity and its ADA2 isoenzyme were both found to be increased, distinct correlation patterns were observed with some of the prognostic factors. It can be speculated that increased ADA and isoenzyme activities in serum originated from sources other than the breast tumors.     

Sex differences in adenosine deaminase activity of stroke patients.

BACKGROUND: Adenosine deaminase (ADA) catalyzes the irreversible hydrolytic deamination of adenosine to inosine. The purpose of this study was to determine the plasma activities of total adenosine deaminase (ADA T), and its isoenzymes, ADA1 and ADA2, and ADA1/ADA2 ratio of male and female ischemic stroke patients. METHODS: We determined activities of plasma ADA T, ADA1, ADA2 and ADA1/ADA2 ratio in 30 patients (15 men and 15 women) with acute ischemic stroke within 12 h of the onset of the attack, as well as in 30 control subjects (15 men and 15 women) of comparable age. RESULTS: There were significant differences between the ADA1 activity and ADA1/ADA2 ratio in male and female stroke patients (p<0.05). Compared with male stroke subjects, females had higher ADA1 activity and ADA1/ADA2 ratios. There were no significant differences between activities of ADA T and ADA2 in men and women of the stroke and control groups. In addition, the Canadian Neurological Scale in men was significantly higher than that of women in the stroke group (p<0.05). CONCLUSIONS: Our results suggest that the primary mechanism in men with ischemic stroke might involve the reduction of ADA1 activity. The reduction is probably an adaptation mechanism for induced increase in adenosine availability and protection of brain to ischemic injury.     

白细胞介素-23在结核性脑膜炎早期诊断中的应用价值

目的检测早期结核性脑膜炎患者脑脊液中白细胞介素-23(IL-23)水平,探讨其在结核性脑膜炎发病机制中可能的作用及其临床意义。方法应用双抗体夹心酶联免疫吸附测定法,检测40例早期结核性脑膜炎治疗前以及治疗后以及37例病毒性脑膜炎患者脑脊液中IL-23的水平。结果与病毒性脑膜炎患者相比,结核性脑膜炎患者脑脊液中IL-23水平明显升高(P<0.01),而结核性脑膜炎患者脑脊液中IL-23水平在治疗1周后即明显下降(P<0.01),但仍较病毒性脑膜炎患者水平高(P<0.05)。结论 IL-23水平检测对了解结核病的活动性、判断病情及预后、监测疗效有一定的参考作用。     

MRI联合脑脊液检测在诊断中枢神经感染中有较高临床价值

目的探讨MRI联合脑脊液（CSF）检查在诊断和鉴别中枢神经感染中的临床价值。方法选取2019年1月~2020年5月在我院治疗的中枢神经系统感染性疾病患者151例,其中病毒性脑膜炎84例,化脓性脑膜炎35例,结核性脑膜炎32例,均给予MRI检查,检查CSF中的乳酸脱氢酶（LDH）、蛋白、乳酸和白细胞计数（WBC）。结果结核性脑膜炎MRI异常检出率高于病毒性脑膜炎和化脓性脑膜炎（P < 0.05）;病毒性脑膜炎和化脓性脑膜炎MRI异常检出率比较差异无统计学意义（P > 0.05）;病毒性脑膜炎病灶区域脑膜强化检出率高于化脓性脑膜炎和结核性脑膜炎（P < 0.05）;化脓性脑膜炎病灶呈环形强化检出率高于病毒性脑膜炎（P < 0.05）;结核性脑膜炎颅底脑膜强化检出率高于病毒性脑膜炎和化脓性脑膜炎（P < 0.05）;病毒性脑膜炎CSF中LDH、蛋白、乳酸和WBC明显低于化脓性脑膜炎和结核性脑膜炎（P < 0.05）;结核性脑膜炎CSF中LDH高于化脓性脑膜炎（P < 0.05）,而蛋白和WBC低于化脓性脑膜炎（P < 0.05）;筛选出LDH（X₁）、蛋白（X₂）和WBC（X₃）3个指标建立判别函数,即：Y_病脑=-0.056X₁- 0.065X₂-0.062X₃+1.168,Y_化脑=-0.041X₁+0.102X₂+0.089X₃-1.102,Y_结脑=0.112X₁-0.057X₂-0.078+1.032;MRI联合CSF参数函数诊断病毒性脑膜炎的敏感度、特异性和准确率分别为79.76%、74.63%和77.48%,诊断化脓性脑膜炎的敏感度、特异性和准确率分别为80.00%、81.03%和80.79%,诊断结核性脑膜炎的敏感度、特异性和准确率分别为78.13%、84.87%和83.44%。结论MRI联合CSF检测在诊断和鉴别中枢神经感染中有较高应用价值,值得临床使用。     

Usefulness of interleukin 6 levels in the cerebrospinal fluid for the diagnosis of bacterial meningitis

Purpose

Interleukin 6 (IL-6) is a proinflammatory cytokine produced during infections. We hypothesized that IL-6 levels in the cerebrospinal fluid (CSF) would be elevated in bacterial meningitis and useful for diagnosing and predicting neurologic outcomes.

Materials and methods

For the differentiation of bacterial meningitis, serum and CSF samples were obtained from patients with an altered level of consciousness. Patients were classified into 3 groups: bacterial meningitis, nonbacterial central nervous system disease, and other site sepsis.

Results

Of the 70 patients included in this study, there were 13 in the bacterial meningitis group, 21 in the nonbacterial central nervous system disease group, and 36 in the other site sepsis group. The CSF IL-6 level was significantly higher in the bacterial meningitis group than in the other 2 groups (P < .0001). Of the 5 CSF parameters assessed, CSF IL-6 level exhibited the largest area under the receiver operating characteristic curve (0.962), with a cut-off value of 644 pg/mL (sensitivity, 92.3%; specificity, 89.5%). To examine a potential association between a high CSF level and neurologic outcome, CSF IL-6 levels were divided into 4 quartiles, and each level was compared with the frequency of a good neurologic outcome. The frequency of a good neurologic outcome was significantly lower in the highest CSF IL-6 quartile than in the other 3 quartiles (odds ratio, 0.18; 95% confidence interval, 0.05-0.69; P = .013).

Conclusions

Measurement of the CSF IL-6 level is useful for diagnosing bacterial meningitis.     

Plasma adenosine deaminase activity among HIV1 Clade C seropositives: relation to CD4 T cell population and antiretroviral therapy

BACKGROUND: Plasma adenosine deaminase and its isoenzymes(s) activities have been used as diagnostic marker for intracellular parasitism, including HIV infection, and malignancy of immune cells. HIV infection being primarily targeted against CD4 cells, it would be of interest to relate the activity of total plasma ADA and isoenzymes fractions to immune status and antiretroviral therapy. METHODS: In the present study, plasma total ADA activity (ADAT) including ADA1 and ADA2 isoenzyme(s) were assayed among HIV seropositive Clade C (n=90) comprising both asymptomatic (n=71) and symptomatic (n=19) and compared with that of HIV seronegatives (n=35). RESULTS: A significant increase in the activity of ADAT (16.30+/-0.80 v/s 6.18+/-0.30) as well as ADA1 (6.50+/-0.42 v/s 2.34+/-0.16) and ADA2 (9.79+/-0.53 v/s 3.85+/-0.23) isoenzyme(s) among the asymptomatic as well as the symptomatic subjects as compared to respective controls was noted. Increase in plasma ADAT activity, including ADA1 and ADA2 isoenzyme(s), were found to have negative correlation with CD4 counts (r, -0.273; p<0.05). The increased plasma ADAT activity among the asymptomatic HIV seropositive with CD4 counts>500 (13.2+/-1.65; p<0.01) as well as those who were on antiretroviral therapy (19.31+/-1.36; p<0.001) was evident. CONCLUSIONS: These findings suggest that plasma ADA can be a sensitive marker of an ongoing biological insult to host tissues either because of infection and/or side effects of medication. Measurement of plasma ADA activity, along with serological evidence for HIV infection may provide an alternate laboratory tool to monitor intracellular parasitism including secondary infection vis a vis the after effects of therapeutic outcome.