CD48 may serve as an accessory molecule for the activation of a subset of human gamma/delta T cells.

To further assess the role of CD48 in the interaction of human gamma/delta T cells with their specific target, we generated two series of alloreactive clones, L and K. These clones express a V1-D-J1-C delta chain associated to V3-J2-C2 (L) or V2-J2-C2 (K) gamma chain. Functionally they were CTLs able to lyse the sensitizing B-cell line E418. The cytotoxicity of the L and K clones toward E418 was inhibited by anti-CD48 mAb. That of the L clones was also inhibited by anti-HLA class I mAbs. Variation in L and K lysis profile was observed against a panel of CD48+ targets, further strengthening the argument that they display distinct specificities and suggesting that they do not recognize CD48. Heterogeneity in TCR gene segment usage, MHC-dependent recognition of E418 by the L clones, and resistance of some CD48+ targets strongly suggest that CD48 itself does not interact with L and K TCR. Transfection of CHO cells with CD48 induced killing by the K clones. This killing was inhibited by anti-CD48 mAbs. Taking into account the recent reports on CD48 as an accessory molecule, our results suggest that by binding to CD2 (and/or an unknown ligand), CD48 may serve to strengthen E/T interaction and may contribute to the activation of a minor subset of gamma/delta T cells.

Can intrapleural C-reactive protein predict VATS pleurodesis failure?

BACKGROUND: Intrapleural inflammatory reaction after surgery for spontaneous pneumothorax is a key indicator whether an effective pleurodesis has been achieved. In this study, we tested the hypothesis that intrapleural C-reactive protein (CRP) might precisely quantify the postoperative pleural inflammation, offering potentially useful information for patient management. METHODS: The study population consisted of 75 consecutive patients who underwent video-assisted thoracoscopic pleurectomy or pleural abrasion for spontaneous pneumothorax between April 2003 and August 2004. We assessed CRP levels in pleural and blood samples taken daily in the first 4 postoperative days. RESULTS: Intrapleural CRP profile was significantly lower in patients who underwent pleural abrasion, in younger patients (< 25 years) and in patients who were not drained before surgery. Patients with pleurodesis failure had a lower CRP peak with a delayed peak. Receiving operating characteristics (ROC) analysis showed that the cutoff value of intrapleural CRP for pleurodesis failure was 25 mg/l on the second postoperative day (sensitivity 87.5 %, specificity 66.6 %, positive predictive value 24.1, negative predictive value 97.7 %). CONCLUSIONS: Pleural CRP levels of less than 25 mg/l on the second postoperative day indicate only a moderate pleural inflammation.

Expansion by folinic acid of the peripheral blood progenitor pool after chemotherapy: its use in autografting in acute leukaemia.

We have tested folinic acid (FA) for ability to increase peripheral blood stem cells (PBSC) after chemotherapeutic aplasia in acute leukaemia. Five adult patients (four AML, one ALL) entered the study, each patient underwent two series of three leukapheresis, the first following induction chemotherapy and the second following the first course of consolidation. The first leukapheresis of each series was done when the white blood cell count reached 10(9)/l with subsequent leukapheresis every other day. Folinic acid (Lederle Laboratories, France) was administered at a dose of 50 mg (i.v.) per day, 15 days from initiation of chemotherapy and continuing through the third leukapheresis of the series (days 25-30). PBSC were collected on a Haemonetics V50 cell separator. In these five cases we observed an increased yield of both colony-forming units, granulocyte macrophage (CFU-GM) and burst forming units-erythroid (BFU-E) expressed per ml of cytapheresis product: CFU-GM x 18, BFU-E x 3 and if expressed per 10(4)/kg of body weight: CFU-GM x 30, BFU-E x 3 (CFU-GM P less than 0.05, BFU-E less than 0.01). Long-term blood culture (LTSC) from FA stimulated leukapheresis, in an attempt to quantitate the most primitive stem cells, demonstrated that this expansion of the PBSC was sustained in time. We found by means of LTSC that FA did not stimulate CFU-L from patients with AML (two cases tested). Finally two AML patients were grafted with FA-PBSC after Cytotoxan and total body irradiation (TBI). Haematopoietic reconstitution was rapid complete and sustained in time in both patients. This indication for folinic acid should be further studied with or as an alternative to haematopoietic growth factors.