Expansion of a CD26low Effector TH Subset and Reduction in Circulating Levels of sCD26 in Stable Allergic Asthma in Adults.

BACKGROUND AND OBJETIVE: The pathogenesis of asthma is dependent on the balance between regulatory and effector T cells, which display differential expression of CD25 and CD26. Therefore, alteration of circulating levels of sCD25 and sCD26 during allergic asthma could be conditioned by changes in leukocyte phenotype. Objectives: To analyze expression of CD25 and CD26 on T lymphocytes and their soluble derivatives (sCD25, sCD26) during stable phases of moderate-severe allergic asthma. METHODS: Cross-sectional study with 2 adult cohorts of allergic asthmatics. Clinical, anthropometric, pulmonary, hematological, and biochemical parameters were measured. Phenotyping was performed with flow cytometry in both circulating and cultured leukocytes. Dipeptidyl peptidase 4 (DPP4) activity was assayed in culture supernatants. RESULTS: In vitro studies revealed upregulation of CD26 on human T lymphocytes upon activation, especially under TH17-favoring conditions, and a correlation with soluble DPP4 activity (rs=0.641; P<.001). CD26 expression on lymphocytes was higher in asthmatics, while serum sCD26 was lower in women and patients. The latter finding could be associated with an expanded CD25low/CD26low/CD127low subset of effector CD4+ T cells in allergic asthma, with no changes in Treg percentages. However, women showed an increased Teff/Treg ratio, which could explain their greater susceptibility to asthma. CONCLUSIONS: Allergic asthma causes an increment in CD25lowCD26low helper T cells detected in stable stages. These changes are mirrored in serum and should be considered in the light of the downmodulating role of CD26 in major chemokines related to the pathogenesis of asthma such as CCL11 (eotaxin), CCL5 (RANTES), and CXCL12a (SDF-1α).

The CD14 (-159 C/T) SNP is associated with sCD14 levels and allergic asthma, but not with CD14 expression on monocytes.

LPS-ligation to CD14/TLR-4 on monocytes/macrophages triggers the production of IL-12-family cytokines. IL12/18 promote TH1-differentiation, counteracting the TH2-driven asthma. Therefore, CD14 modulation could alter the TH2-differentiation and should be taken into account when studying asthma. To analyse the alteration in CD14 levels and its association with CD14 (-159 C/T) SNP (rs2569190) in Caucasian adults with stable allergic asthma, we performed a cross-sectional study (277 healthy subjects vs. 277 patients) where clinical parameters, CD14 values and the CD14 (-159 C/T) SNP were studied. Apart from typical biomarkers, we found an increment of neuron-specific enolase (NSE) in allergic asthma, probably linked to monocyte activity. Indeed, we evidenced increased monocyte numbers, but lower CD14 expression and normalised sCD14 values in patients. Moreover, we noticed an association of the T allele (P = 0.0162) and TT genotype (P = 0.0196) of the CD14 SNP with a decreased risk of allergic asthma and augmented sCD14 levels. In conclusion, monocyte CD14 expression and normalized sCD14 values were reduced in stable state asthmatics, and this could be related to the presence of an expanded CD14low monocyte subset. This study also demonstrates that the CD14 (-159 C/T) polymorphism is a risk factor for moderate-severe allergic asthma in adult Caucasians.

Utility of tumour markers in the diagnosis of neoplastic pleural effusion.

Approximately 20% of pleural effusions are caused by neoplastic processes. Although cytology is the most specific routine diagnostic procedure, its sensitivity of 50-60% is insufficient, and thus diagnosis is usually carried out by more invasive techniques such as pleural biopsy, thoracoscopy or thoracotomy. The object of this study is to evaluate the use of determining some tumour markers in pleural fluid obtained by thoracocentesis for diagnosis of neoplastic pleural effusion. Patients (271) with pleural effusions were classified in five groups: I: neoplasms n = 88; II: tuberculosis n = 63; III: parapneumonics n = 53; IV: miscellaneous exudates n = 39 and V: transudates n = 28. The tumour markers studied were: carcinoembryonic antigen (CEA), CA 125, squamous cell carcinoma antigen (SCC), and neuron specific enolase (NSE). The tumour makers had the following diagnostic efficiencies for neoplastic origin of the pleural effusion: CEA 76% (sensitivity 31%, specificity 93%); CA 125 66% (70% and 61%); SCC 65% (48% and 80%) and NSE 53% (30% and 89%). The diagnostic efficiencies for pulmonary neoplastic origins were 68% for NSE (sensitivity 83%, specificity 53%); 65% for SCC (54% and 75%); 63% for CEA (80% and 48%) and 61% for CA 125 (79% and 42%). We believe that the routine testing of tumour markers in pleural fluid obtained by thoracocentesis would greatly increase diagnostic effectiveness and could avoid the practice of more aggressive diagnostic techniques on the patient.

Lymphocyte populations in tuberculous pleural effusions.

Different systemic and local responses to mycobacterial antigens suggest an active compartmentalization of responsive lymphocytes to tubercular antigens. This fact, observed in pleuritic processes, raises doubts about the accuracy of information obtained in the study of cells taken solely from peripheral blood. For this reason we decided to study the concept of compartmentalization in 140 patients suffering from pleural effusions. Patients were classified into six groups according to the aetiology of the effusion: group I, tuberculous, n = 23; group II, paraneoplastic, n = 41; group III, metapneumonic empyematous, n = 5; group IV, transudate, n = 38; group V, miscellaneous exudate, n = 19; group VI, unknown aetiology, n = 14. In each group we studied the lymphocyte population by using flow cytometry with doubly fluorescent monoclonal antibodies: B [expressing human lymphocyte antigen (HLA)-DR on the surface], T (CD3+), CD4+ and CD8+, and the subpopulation of activated T lymphocytes (together expressing CD3 and HLA-DR on the surface) (CD3+DR+). The study of these subpopulations in peripheral blood did not yield valuable results, but the CD3+DR+ population in pleural fluid demonstrated a diagnostic efficiency of 84% [positive predictive value (PPV) 51%, negative predictive value (NPV) 96%] at a cut-off value of 80.4 cells/mm3. The CD3+DR+ pleural fluid/peripheral blood ratio demonstrated an efficiency of 83% (PPV 50%, NPV 96%), and showed a statistically significant difference (P < 0.02) with regard to all the diagnostic groups, with the exception of the paraneoplastic effusions. The lymphocytic subpopulations study confirms the concept of compartmentalization in tuberculous pleuritis, as shown by the greater number of activated T lymphocytes present in pleural fluid in comparison with peripheral blood in tuberculous pleuritis, a 98% efficiency of adenosine deaminase (ADA) determination in pleural fluid versus a 50% value in peripheral blood, predominance of helper cells (CD4+) in pleural fluid and suppressor cells (CD8+) in peripheral blood, a greater CD4+/CD8+ ratio in pleural fluid than in peripheral blood, and a significant correlation of ADA-CD3+DR+ in pleural fluid, which does not occur in peripheral blood.

Can tuberculous pleural effusions be diagnosed by pleural fluid analysis alone?

OBJECTIVE: To assess whether pleural fluid analysis (PFA) can confidently diagnose tuberculous pleural effusion (TPE). METHODS: PFA of 548 TPEs was performed between January 1991 and December 2011. The control group consisted of patients with malignant PE (MPE), complicated parapneumonic/empyema (infectious) PE (IPE), miscellaneous PE (MisPE) and transudative PE (TrPE). RESULTS: The PFA of 548 histologically or culture-positive consecutive cases of TPE was compared with that of 158 consecutive cases of MPE, 113 cases of IPE, 37 cases of MisPE and 115 cases of TrPE. Statistically significant differences were noted in pleural fluid glucose, pH, cholesterol, triglycerides, adenosine deaminase (ADA), and total percentages of lymphocytes, neutrophils and macrophages when TPEs were compared to all other groups. Of the TPEs, 99.1% were exudates. Pleural fluid protein ≥ 5.0 g/dl, lymphocytes > 80% and ADA > 45 U/l were diagnostic of TPE, with a specificity of 100%, a sensitivity of 34.9% and an area under the curve of 0.975. CONCLUSION: PFA alone was diagnostic in one third of the TPE cases, with a high probability in nearly 60%.

Determination of iron by the Ferrochem II: interference by tuberculostatics.

Iron levels in samples from certain treated tuberculous patients are underestimated by the Ferrochem II analyser. Of the tuberculostatic drugs examined for a possible interference, isoniazid, ethambutol, rifampicin, pyrazinamide and Rifater (a mixture of rifampicin, isoniazid and pyrazinamide), only pyrazinamide and Rifater (due to its pyrazinamide content) were associated with iron levels differing significantly (p < 0.001) from those of controls, with means of -317.2 and -185.6 mumol l-1 for pyrazinamide and Rifater respectively as against 9.91 mumol l-1 for the controls. The negative interference (I) due to pyrazinamide was independent of iron level in the samples but dependent on pyrazinamide concentration in the same (P) (r = 0.9993), I = -0.4380P-0.4276.