Markers of platelet, endothelial cell and blood coagulation activation in leprosy patients with antiphospholipid antibodies.

OBJECTIVE: To evaluate plasma levels of markers of platelet, endothelial cell and blood coagulation activation in leprosy patients with or without antiphospholipid antibodies (aPL) and to compare them to those found in patients with antiphospholipid syndrome (APS). METHODS: 42 patients with leprosy (35 lepromatous and 7 borderline): 29 aPL(+) and 13 aPL(-), as well as 26 healthy subjects as normal controls (NC) and 79 control aPL patients without leprosy (59 with and 20 without APS) were included in the study. Plasma soluble P and E selectin (sPsel and sEsel), and VCAM-1 (sVCAM-1), prothrombin F1 + 2 fragment (F1 + 2), thrombin-antithrombin complexes (TAT) and D dimer (DD) were measured by ELISA. The protein C pathway was assessed by the ProC global test. RESULTS: Leprosy patients with aPL presented increased median levels of sPsel [ng/ml (82.0 vs 36.0, p < 0.001)] and sVCAM-1 [ng/ml (495 vs 335, p < 0.001)] compared to NC, as observed in control aPL patients without leprosy. Levels of sPsel in aPL(+) patients with leprosy were significantly higher than in aPL(-) ones (52.5 ng/ml), p = 0.005. However, plasma markers of thrombin generation were increased in control aPL patients without leprosy but not in those with leprosy. ProcC global test was abnormal in 24.1% of leprosy patients with aPL compared to 4.4% of NC (p < 0.024), and to 57.2% of control patients with aPL without leprosy (p = 0.005). CONCLUSIONS: We demonstrated that although patients with leprosy present a high prevalence of aPL, and platelet and endothelial cell activation in vivo to the same extent than patients with APS, they do not show a procoagulant state.

Markers of platelet, endothelial cell and blood coagulation activation in leprosy patients with antiphospholipid antibodies

OBJECTIVE: To evaluate plasma levels of markers of platelet, endothelial cell and blood coagulation activation in leprosy patients with or without antiphospholipid antibodies (aPL) and to compare them to those found in patients with antiphospholipid syndrome (APS). METHODS: 42 patients with leprosy (35 lepromatous and 7 borderline): 29 aPL(+) and 13 aPL(-), as well as 26 healthy subjects as normal controls (NC) and 79 control aPL patients without leprosy (59 with and 20 without APS) were included in the study. Plasma soluble P and E selectin (sPsel and sEsel), and VCAM-1 (sVCAM-1), prothrombin F1 + 2 fragment (F1 + 2), thrombin-antithrombin complexes (TAT) and D dimer (DD) were measured by ELISA. The protein C pathway was assessed by the ProC global test. RESULTS: Leprosy patients with aPL presented increased median levels of sPsel [ng/ml (82.0 vs 36.0, p smaller 0.001)] and sVCAM-1 [ng/ml (495 vs 335, p smaller 0.001)] compared to NC, as observed in control aPL patients without leprosy. Levels of sPsel in aPL(+) patients with leprosy were significantly higher than in aPL(-) ones (52.5 ng/ml), p = 0.005. However, plasma markers of thrombin generation were increased in control aPL patients without leprosy but not in those with leprosy. ProcC global test was abnormal in 24.1 per cent of leprosy patients with aPL compared to 4.4 per cent of NC (p smaller 0.024), and to 57.2 per cent of control patients with aPL without leprosy (p = 0.005). CONCLUSIONS: We demonstrated that although patients with leprosy present a high prevalence of aPL, and platelet and endothelial cell activation in vivo to the same extent than patients with APS, they do not show a procoagulant state.

Interleukin-12 amplifies the M. leprae hsp65-cytotoxic response in the presence of tumour necrosis factor-alpha and interferon-gamma generating CD56+ effector cells: interleukin-4 downregulates this effect.

Interleukin-12 (IL-12) is a major immunomodulatory cytokine that represents a functional bridge between the early resistance and the subsequent antigen specific adaptive immunity. TNF-alpha and IFN-gamma have an important role in the generation of hsp65 specific cytotoxic T lymphocytes (CTL) that lyse hsp65-pulsed autologous macrophages (hsp65 CTL). Since a positive feedback mechanism between TNF-alpha, IFN-gamma and IL-12 has been described, we undertook to evaluate the role of IL-12 on the hsp65 CTL generation in leprosy patients. Our results show that the presence of IL-12 during the first 24 h of the in vitro antigen stimulation amplifies the hsp65 cytotoxic response whenever both IFN-gamma and TNF-alpha are present. The addition of these three cytokines (CKs) was able to abrogate the inhibitory effect of IL-10 on hsp65 CTL in cells from paucibacillary patients (PB) but not that of IL-4 in PB and normal controls (N). Both IL-12 or anti IL-4 enhanced the cytotoxic activity in cells from multibacillary patients (MB). Anti IL-4 upregulated the binding of IFN-gamma and did not modify that of TNF-alpha so the low CTL activity could be as a result of IL-4 by a decrease of the IFN-gamma binding on MB cells. Cells from those MB patients taking thalidomide (MB-T) did neither bind IFN-gamma nor TNF-alpha even when antigen or anti-IL-4 were added, demonstrating that thalidomide inhibits either the in vitro binding or receptor expression of both TNF-alpha and IFN-gamma. Development of CD56 effector cells during the hsp65 stimulation was observed in PB and N by the addition of IL-12 plus TNF-alpha and IFN-gamma, while in MB and MB-T anti IL-4 was also required. So, the inhibitory effect of IL-4 on either production of IFN-gamma, TNF-alpha and/or IL-12 or their receptors could be the mechanism underlying the lack of the hsp65 CTL generation in cells from MB.

Interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) are necessary in the early stages of induction of CD4 and CD8 cytotoxic T cells by Mycobacterium leprae heat shock protein (hsp) 65 kD.

Cytotoxic T cells (CTL) may play an important role in host defence against mycobacterial infections. CD4 CTL are preferentially induced by mycobacteria, but both CD4 and CD8 CTL may be necessary components of a protective immune response. The 65-kD mycobacterium heat shock protein (hsp65) is a poor inducer of CTL in multibacillary leprosy (MB) patients. In this study we evaluate the possible role of cytokines in modulating the cytotoxic activity of CTL from leprosy patients and normal individuals (N) against autologous macrophages presenting Mycobacterium leprae hsp65. Our results show that hsp65-specific CTL were generated from both CD4 and CD8 lymphocytes. In N, individual cytokines as well as the combination of them were able to modify the hsp65-induced cytotoxic activity. The effect of cytokines on leprosy patients' lymphocytes was different in MB and paucibacillary (PB) patients. Thus, IL-6, IL-2, IFN-gamma or TNF-alpha did not modify the generation of hsp65-CTL from either MB (with or without an erythema nodosum episode (ENL)) or PB. In all the patients the simultaneous addition of two cytokines was required in order to increase CTL generation. In MB, IL-6 plus IFN-gamma or IL-2 increased both CD4 and CD8 CTL, while TNF-alpha plus IFN-gamma up-regulated only CD4 CTL. In PB, CD8 CTL were prominent with IL-6 plus IFN-gamma, while the increase was significant in CD4 CTL with IL-6 plus IL-2. Down-regulation of CTL was observed by addition of IL-4, IL-10, anti-IFN-gamma or anti-TNF-alpha in N controls. Our data demonstrate that IFN-gamma and TNF-alpha must be present for at least the first 60 h of the induction stage in order to generate full hsp65 CTL. Hence, IFN-gamma and TNF-alpha would be key factors in the generation of hsp65 CTL.