Cytomegalovirus infection in systemic necrotizing vasculitis: causative agent or opportunistic infection?

We report on a 69-year-old woman who presented with myalgia, hearing impairment, fever, night sweats, weight loss, muscular weakness, paresthesia, hypesthesia, and hypalgesia. Sural nerve biopsy showed demyelinative and axonal polyneuropathy due to necrotizing vasculitis with fibrinoid necrosis. A positive test for antineutrophil cytoplasmic antibodies (ANCA) with a perinuclear immunofluorescence pattern directed against myeloperoxidase was more suggestive of microscopic polyangiitis (MPA) than of polyarteritis nodosa (PAN), the possible differential diagnoses. In addition, positive tests for cytomegalovirus (CMV) antibodies (immunoglobulin (Ig)M and IgG) and the detection of CMV-DNA in sputum specimens by polymerase chain reaction (PCR) were indicative of active CMV infection. Treatment with ganciclovir and anti-CMV immunoglobulin in addition to prednisolone medication for 6 months resulted in rapid improvement of the clinical symptoms without relapse. CMV infection has been described to be related to ANCA-associated vasculitis in non-immunocompromized patients and may be either a causative agent or an opportunistic infection. Identification of a viral etiology in patients with atypical ANCA-associated vasculitides may lead to different, less aggressive treatment approaches, including antiviral therapy. Received: 5 April 2000 / Accepted: 16 June 2000     

Respiratory pasteurellosis: infection or colonization?

Respiratory infection by Pasteurella multocida is uncommon and usually occurs in patients with an underlying lung disease, advanced age and/or immunodepression. In this study, we describe the clinical and microbiological characteristics of a series of 14 patients in whom Pasteurella multocida was isolated from lower respiratory tract samples, over a period of 21 y (1986-2006). Differentiation between colonization and infection allows establishment of early antibiotic treatment.     

Mixed infection in ticks: a rule or an exception?

A hypothesis for the independence of acts of infection in ticks with pathogens from each other in mixed infection has been tested on the basis of the data available in the literature. In most cases the number of ticks with mixed infection is consistent with the independence hypothesis and fails to reinforce the statement that there is antagonism of pathogens. But in some reports the number of mixed-infected ticks is 3-13 times higher than the calculated number according to the accepted hypothesis. These facts suggest that the natural tolerance of ticks to pathogens due to primary infection may be reduced. Other possible reasons for differences in the actual and calculated number of mixed infected ticks are also discussed.     

Respiratory syncytial virus infection: an emerging or unappreciated infection?

Respiratory syncytial virus (RSV) is a ubiquitous cause of respiratory infection with a worldwide distribution and seasonal occurrence. Natural immunity does not normally follow infection, and reinfection is the rule. Reinfection may even occur within a single season. Although its role in serious lower respiratory tract infection (LRTI) in infants is well recognized, the importance of RSV in disease of older children, adults and, especially in the elderly, is poorly appreciated. In large surveillance studies, RSV is at least as important in contributing to respiratory morbidity and mortality as influenza. These data would suggest that tens of millions of Americans suffer respiratory disease (LRTI and upper respiratory tract infection [URTI]) from RSV each winter. In addition, otitis media and episodic bronchospasm are complications following RSV infection. Unfortunately, there is no vaccine yet available for prevention. Prevention of disease with a hyperimmune globulin (RSVIG) and with a monoclonal antibody (MAb) (palivizuMab) is possible, but only for those neonates and infants at highest risk of morbidity and mortality from RSV infection. Therapy with the only approved antiviral for this indication, ribavirin, is difficult, is of questionable efficacy, and the compound itself is teratogenic. Infection by RSV constitutes an enormous but unappreciated medical need worldwide.     

Increased haemoglobin A2 percentage in HIV infection: disease or treatment?

An elevated haemoglobin A2 percentage has been reported in HIV-infected patients, possibly attributable to therapy. In cross-sectional and cohort studies we have established that A2 is often elevated in untreated patients; a further rise during treatment is attributable specifically to zidovudine. The haemoglobin A2 may be high enough to lead to a misdiagnosis of beta thalassemia trait if there is a lack of awareness of this unexpected effect of HIV infection and its treatment.     

cAMP during HIV infection: friend or foe?

Intracellular levels of cyclic adenosine 3',5'-monophosphate (cAMP) are important regulators of immune cells, partially determining the balance between activation and suppression. In this review, we discuss the mechanisms by which HIV infection increases cAMP levels in T cells, as well as the effect of cAMP on HIV-specific responses and its effect on HIV replication and infection. Results suggest that increased cAMP levels during HIV infection may have a dual and opposite roles. On the one hand, they could have a protective effect by limiting viral replication in infected cells and decreasing viral entry. On the other hand, they could have a detrimental role by reducing HIV-specific antiviral immune responses, thus reducing the clearance of the virus and contributing to T cell dysfunction. Future studies are thus needed to further define the beneficial versus detrimental roles of cAMP, as they could help establish new therapeutic targets to combat HIV replication and/or identify novel ways to boost antiviral immune responses.     

Granulocytes: effector cells or immunomodulators in the immune response to helminth infection?

Granulocytes are effector cells in defence against helminth infections. We review the current evidence for the role of granulocytes in protective immunity against different helminth infections and note that for each parasite species the role of granulocytes as effector cells can vary. Emerging evidence also points to granulocytes as immunomodulatory cells able to produce many cytokines, chemokines and modulatory factors which can bias the immune response in a particular direction. Thus, the role of granulocytes in an immunomodulatory context is discussed including the most recent data that points to an important role for basophils under this guise.     

Oral contraceptive pills: Risky or protective in case of Trichinella spiralis infection?

The aim of this study was to investigate how Trichinella spiralis infection can be affected by contraceptive pills in vivo. Methods included six groups of female Wistar rats; healthy, Trichinella infected, receiving combined contraceptive pills (COCPs), receiving progestin only pills (POPs), infected receiving COCPs and infected receiving POPs. Parasite burden was measured; adult worm counts, gravidity, larvae and reproductive capacity index). Histopathological examination, immunohistochemical detection of C‐kit+ mast cells and Foxp3+ T‐reg. cells in intestinal sections, eosinophils muscle infiltration and CPK level were performed. Rats infected and receiving COCPs showed a significant increase in parasitic burden, and infected receiving POPs showed a significant reduction compared to infected only, with a significant increase in nongravid females (Mean total worms=964.40±55.9, 742±52.63, 686±31.68, larvae/g=5030±198.75, 2490±143.18 and 4126±152,91, respectively). Intestinal sections from infected receiving COCPs showed intact mucosa (though the high inflammatory cells infiltrate), and significant increase in C‐kit+ mast cells number and intensity (30.20±4.15 and 60.40±8.29), and Foxp3+ T‐reg. cells (10±1.58). Infected receiving POPs showed a significantly less CPK (5886±574.40) and eosinophilic muscle infiltration (58±13.51). Oestrogen‐containing pills established a favourable intestinal environment for Trichinella by enhancing Foxp+T‐reg. cells and stabilizing C‐kit+mast cells, while POPs gave a potential protection with less gravidity, larval burden and eosinophilic infiltrate.     

Cryoglobulinemia and progression of fibrosis in chronic HCV infection: cause or effect?

OBJECTIVES: Mixed cryoglobulinemia (MC) is the most common extrahepatic manifestation of HCV infection. The aim of this study is to determine the prevalence of MC in HCV infected Greek patients and to identify if it is associated with liver histology or the mode of HCV transmission. METHODS: One hundred and twenty-six patients with chronic HCV infection were evaluated for the presence of serum cryoglobulins, autoantibodies and viral markers. One hundred and eighteen of them underwent liver biopsy and each specimen was evaluated according to the grading and staging system described by Ishak et al. RESULTS: Cryoglobulins were detected in 37/126 (29.4%) HCV patients and cryocrit values ranged between 0.5 and 6.5%. Only two patients presented clear clinical manifestations of MC. In patients with MC, a higher grading (6.40+/-2.06 vs. 5.27+/-2.55, p=0.013) and staging score (3.71+/-1.45 vs. 2.83+/-1.84, p=0.007) was noted in liver biopsy compared to those without MC. Logistic regression analysis identified staging score (OR, 1.33; CI, 1.06-1.66, p=0.015) as the only independent variable associated with cryoglobulinemia. Correlation between the presence of cryoglobulins and the mode of HCV transmission was not found. CONCLUSIONS: Greek patients with chronic HCV infection have high prevalence of cryoglobulinemia. A clear association between the presence of serum cryoglobulins and staging score of chronic hepatitis was found, with no difference in patients' age or the duration of infection. It is possible that cryoglobulinemia results in more rapid hepatic fibrosis in HCV infected patients.