Immune thrombocytopaenic purpura: an autoimmune cross-link between infections and vaccines

Immune thrombocytopaenic purpura (ITP) is an autoimmune systemic disease detectable by the presence of low blood platelets count (<10(5)/µl) and the production of autoantibodies against glycoproteins expressed on the platelet surface. The clinical course is often acute, and life-threatening events may occur especially in children, with 52% of paediatric patients recovering either spontaneously or after treatment. A chronic ITP evolution is observed in 64% of adults, of whom 12% will develop an overlapping autoimmune disease. Several microbial agents such as CagA-positive Helicobacter pylori or Candida albicans and a number of viruses including CMV, EBV or HIV can potentially trigger ITP through molecular mimicry. Moreover, ITP improves after treatment of the underlying infection. Similarly, vaccines such as MMR may prompt ITP (IRR 5.48, 1.61-18.64, p < 0.006). Early recognition of the underlying microbial trigger and the removal of modifiable aetiopathogenetic factors should be integrated as a complementary treatment strategy in all patients who do not readily improve with standard ITP care.

Role of oral sildenafil in the treatment of right ventricular dysfunction after heart transplantation

OBJECTIVE

Right ventricular dysfunction (RVD) after heart transplantation is a major complication, especially in patients with pulmonary hypertension (PH). Herein we have presented our initial experience with oral sildenafil for RVD following heart transplantation.

MATERIALS AND METHODS

From February 2006 to February 2008, 10 patients (7 males and 3 females) of overall mean age of 56.7 +/- 9.5 years suffered from acute RVD immediately after heart transplantation. Preoperative hemodynamic data before and after a vasodilatation test (sodium nitroprusside; NTP) showed: systolic pulmonary arterial pressure (SPAP) 59.5 +/- 12.9 and 44.2 +/- 12.4 mm Hg; cardiac output (CO) 3.3 +/- 0.9 and 3.7 +/- 0.8 L/min; transpulmonary gradient (TPG) 11.7 +/- 3.9 and 8.7 +/- 3.6 mm Hg; and pulmonary vascular resistance (PVR) 3.9 +/- 2.1 and 2.4 +/- 1.3 wood units (WU), respectively. All patients required inotropes and inhaled nitric oxide (iNO) to be weaned from cardiopulmonary bypass (CPB).

RESULTS

Intravenous (IV) or inhaled vasodilators could be weaned using oral sildenafil in all patients. The hemodynamic data obtained during IV or inhaled drugs (between postoperative days 5 and 10) compared with those obtained on sildenafil therapy alone (about 1 month after transplantation) showed a significant decrease in SPAP (39.0 +/- 8.2 vs 32.0 +/- 6.5 mm Hg; P = .049).

CONCLUSION

These data suggested that oral sildenafil may have a role in the treatment of RVD after heart transplantation.

Inhaled nitric oxide versus sodium nitroprusside for preoperative evaluation of pulmonary hypertension in heart transplant candidates

OBJECTIVE

The development of pulmonary hypertension before heart transplantation increases the risk for postoperative right ventricular failure. Reversibility of pulmonary vascular resistance (PVR), which indicates the feasibility of heart transplantation, can be tested with the use of intravenous vasodilators, such as sodium nitroprusside (NaNTP) or prostacyclin. However, the drawback of these drugs is the development of systemic hypotension. The aim of this study was to evaluate the safely and feasibility of inhaled nitric oxide (iNO) compared with sodium nitroprusside to test PVR reversibility, while avoiding systemic hypotension.

MATERIALS AND METHODS

We included all patients who were affected by end stage heart failure undergoing evaluation for heart transplantation if they showed elevated PVR > 2.5 Wood units and mean pulmonary arterial pressure (mPAP) >25 mm Hg. The hemodynamic parameters measured by right heart catheterization were: systolic blood pressure (SBP), mPAP, pulmonary capillary wedge pressure, and cardiac index (CI). The following variables were derived: transpulmonary gradient (TPG) and PVR. All patients were tested by both iNO (20-40 ppm) and intravenous NaNTP, at increasing dosages which were titrated based on systemic pressure. We randomly assigned the order of administration of iNO and NaNTP.

RESULTS

The 9 male candidates has an average age of 56 ± 4 years. Seven of the 9 (71%) had postischemic cardiomyopathy, and 2 had idiopathic cardiomyopathy. We observed a reduction of mPAP (32% and 14%), PVR (41% and 32%), TPG (20% and 26%), and SBP (17% and 5%) and an increase of CI with administration of NaNTP and iNO, respectively.

CONCLUSIONS

We observed a reduction in PVR and mPAP with administration of either iNO and NaNTP. A better effect of NaNTP was attributed to reducted post-load of the left ventricle. However, the main advantage of iNO was the absence of systemic hypotension and its selectivity for pulmonary vascular system, as underscored by TPG reduction.

Analysis of the mucosal immune responses induced by single and trickle infections with the bovine abomasal nematode Ostertagia ostertagi

The purpose of this study was to provide more information on the kinetics of the immunological changes occurring in the abomasal mucosa after single and trickle infections with the bovine parasite Ostertagia ostertagi. The time course analysis of gene expression revealed that the major changes coincided with the emergence of adult worms from the gastric glands. These changes consisted of a simultaneous upregulation of Th1- and Th2-type cytokines. In addition, a single O. ostertagi infection elicited an upregulation of the epithelial-derived cytokine IL33, while TSLP expression levels were not impacted. Apart from the massive increase in inflammatory cytokines IL6, IL17 and IL21, O. ostertagi infection also elicited an upregulation of the immunosuppressors TGFB, IL10 and ARG1, as well as NK and γδ-T cell markers. Furthermore, the cytotoxic factors granulysin, perforin and granzyme B were upregulated following an O. ostertagi infection. Analysis of cytokine transcript levels in animals receiving trickle infections for 60 days showed a similar trend as observed following a single infection except for IL33, IL6, GATA-3, TBX21 and NCR1, which were no longer upregulated after trickle infections. Finally, the long trickle infections were associated with mucosal eosinophilia and mastocytosis.

Monitoring environmental Aspergillus spp. contamination and meteorological factors in a haematological unit

The opportunistic pathogens belonging to the Aspergillus genus are present in almost all seasons of the year, and their concentration is related to meteorological conditions. The high density of Aspergillus spp. conidia in a haematological hospital ward may be a significant risk factor for developing invasive fungal diseases in immunocompromised patients. Aim of the present study was to evaluate the variability of airborne Aspergillus spp. conidia contamination in a Haematological Unit (HU) within a period of 16 months in relation with some meteorological parameters. An environmental Aspergillus surveillance was conducted in the HU in four rooms and their bathrooms, in the corridor and in three external sites using an agar impact sampler. During each sampling, temperature and relative humidity at each site were recorded and current wind speed and rainfall events were taken from the official weather service. Aspergillus spp. conidia concentration differed significantly across the sampling sites. Internal Aspergillus spp. loads were significantly dependent on temperature, internal relative humidity and rain. External conidia concentrations were significantly influenced by outdoor temperature and relative humidity. A suitable indicator was introduced to evaluate the seasonal distribution of Aspergillus spp. conidia in the sampling sites, and a significant dependence on this indicator was observed inside the HU. Seventeen different fungal species belonging to the Aspergillus genus were detected during the sampling period. Aspergillus fumigatus was the most frequently isolated species and its distribution depended significantly on the seasonal indicator both inside and outside the hospital ward.