Infantile herpes simplex encephalitis: diagnostic features and differentiation from non-accidental injury

OBJECTIVES

Neonatal herpes simplex virus (HSV) encephalitis is rare, but associated with considerable morbidity and mortality. After a baby, subsequently proven to have HSE, had initially been diagnosed as non-accidental injury (NAI), we reviewed the clinical features and radiology of infants with HSE recently diagnosed by our laboratory.

METHODS

Screening of cerebrospinal fluid (CSF) samples sent to Oxford for HSV polymerase chain reaction (PCR) analysis, from wide range of British hospitals, identified HSV infected infants. After a diagnosis was made, the case notes and neuroradiology (where available) were reviewed and a limited follow-up was undertaken.

RESULTS

Thirteen infants had HSV encephalitis (HSE), which in four followed a relapsing course. On subsequent assessment six infants had neurological sequelae, six appeared to be normal, and one was lost to follow-up. Neither a history of primary HSV infection in pregnancy, nor skin lesions in the baby, were helpful diagnostically. Magnetic resonance imaging indicated haemorrhage in the cortex, but no subdural haematomata, a hallmark of NAI, in 5/6 infants.

CONCLUSIONS

The early clinical features of HSE and NAI may be indistinguishable. As early diagnosis is important, infants with an unidentified encephalopathic illness should be examined by neuroradiology and their CSF tested for HSV DNA. Together these examinations can confirm and differentiate between those two conditions. Relapsing HSE may mimic recurrent encephalopathy caused by multiple NAIs.

Altered host behaviour: manipulation or energy depletion in tapeworm-infected copepods?

Parasites are able to influence intermediate hosts in a way that optimizes their growth and transmission to the next host. Macrocyclops albidus (Copepoda) suffer from a reduced escaping ability and an increased level of general activity, when infected with Schistocephalus solidus (Cestoda). This facilitates predation by the subsequent host, the three-spined stickleback. However, instead of adaptive host manipulation by the tapeworm, the altered copepod behaviour might be explained more simply as a constraint of the infection. Energy depletion could lead to decreased muscle performance and increased food searching activity. Furthermore, resource allocation among host tissues might change after infection. We therefore analysed the amount of storage lipids and muscle tissue before and after experimental infection. To determine the amount of muscles, we developed a new polarization-microscopic technique. Irrespective of infection, lipids and muscles were predictors of copepod survival. However, we found no effect of the parasite infection on muscles or lipids, and no indication of a change in resource allocation between these tissues. Our study suggests that behavioural changes in infected copepods are mediated by a mechanism different from energy depletion or a re-allocation of resources between muscles and lipids. We rather propose that the tapeworms directly manipulate copepod behaviour.

Management of women with ductal carcinoma in situ of the breast: a population-based study

BACKGROUND

Increasing incidence of ductal carcinoma in situ (DCIS) confronts patients and clinicians with optimal treatment decisions. This multidisciplinary study investigates therapeutic modalities of DCIS in daily practice and provides recommendations on how to increase quality of care.

PATIENTS AND METHODS

All women (n = 116) with unilateral DCIS recorded in the Geneva Cancer Registry from 1995 to 1999 were considered. Information concerned patient and tumor characteristics, treatment and outcome. Factors linked to therapy were determined using a case-control approach. Cases were women with treatment of interest and controls other women on the study.

RESULTS

Most DCIS cases (62%) were discovered by mammography screening. Ninety (78%) women had breast-conserving surgery (BCS), 18 (16%) mastectomy and seven (6%) bilateral mastectomy. Eight (7%) patients had tumor-positive margins, 18 (16%) lymph node dissection and two (1.7%) chemotherapy. Twenty-five per cent of women with BCS had no radiotherapy, three had radiotherapy after mastectomy. Less than 50% underwent breast reconstruction after mastectomy. Method of discovery, multifocality, tumor localization, size and differentiation were linked to the use of BCS or lymph node dissection.

CONCLUSIONS

Because of important disparities in DCIS management, recommendations are made to increase quality of care, in particular to prevent axillary dissection or bilateral mastectomy and to increase the use of radiotherapy after BCS.

To avoid or eliminate: cestode infections in copepods

The outcome of a parasite infection is the result of the interaction between the host and the parasite. In the system we studied, there are 3 critical stages for the outcome of infection of the (intermediate) host, the copepod Macrocyclops albidus, with the cestode Schistocephalus solidus. During the establishment phase of the parasite, the host may firstly avoid ingesting the parasite and, secondly, may prevent the parasite from entering the body cavity and, thirdly, during the growth phase of the parasite, the host's immune system may eliminate the parasite from the body cavity. We were able to study the growth phase separately from the establishment phase. The establishment phase was influenced by characteristics of the host as well as characteristics of the parasites. Small copepods and males performed poorly; they were more often infected and had a lower survival. Parasites from different sib-groups differed in infectivity. During the growth phase some disappearance of parasites was observed. However, this could not be related to any of the studied characteristics of the host, and the sib-groups of parasites did not seem to differ in their likelihood to disappear. Instead, we suggest that disappearance of parasites, once they have entered the body cavity, may be due to intrinsic mortality of the parasites, independent of the host or the sib-group that the parasites belong to. This indicates that the crucial interactions between host and parasite determining the outcome of infection takes place in the short time-period between ingestion and penetration of the gut-wall.

Mechanisms involved in the establishment of tolerance through costimulatory blockade and BMT: lack of requirement for CD40L-mediated signaling for tolerance or deletion of donor-reactive CD4+ cells

We have previously shown that high levels of multiline-age mixed hematopoietic chimerism and systemic T-cell tolerance can be achieved in mice without myeloablation through the use of anti-CD40L and costimulatory blockade alone (plus CTLA4Ig) or with recipient CD8 depletion and allogeneic bone marrow transplantation. Chimeric mice permanently accept donor skin grafts (> 100 days), and rapidly reject third-party grafts. The mechanisms by which costimulatory blockade facilitates the engraftment of allogeneic hematopoietic cells have not been defined. To further understand the in vivo mechanisms by which the administration of anti-CD40L mAb facilitates the engraftment of donor bone marrow and rapidly tolerizes CD4+ T cells, we analyzed the establishment of chimerism and tolerance in CD40L -/- mice. We demonstrate here that anti-CD40L mAb treatment is required only to prevent CD40L/CD40 interactions, and that no signal to the T cell through CD40L is necessary for the induction of CD4+ tolerance. Peripheral deletion of donor-reactive CD4+ T cells occurs rapidly in CD40L -/- mice receiving bone marrow transplantation (BMT), indicating that this deletion in the presence of anti-CD40L is not due to targeting of activated CD4+ cells by the antibody. Complete CD4+ cell tolerance is observed by both skin graft acceptance and in vitro assays before deletion is complete, indicating that additional mechanisms play a role in inducing CD4+ T-cell tolerance as the result of BMT in the presence of CD40/CD40L blockade.

CD4 T cell-mediated alloresistance to fully MHC-mismatched allogeneic bone marrow engraftment is dependent on CD40-CD40 ligand interactions, and lasting T cell tolerance is induced by bone marrow transplantation with initial blockade of this pathway

Costimulatory blockade can be used to promote allogeneic marrow engraftment and tolerance induction, but on its own is not 100% reliable. We sought to determine whether one or the other of the CD4 or CD8 T cell subsets of the recipient was primarily responsible for resistance to allogeneic marrow engraftment in mice receiving costimulatory blockade, and to use this information to develop a more reliable, minimal conditioning regimen for induction of mixed chimerism and transplantation tolerance. We demonstrate that a single anti-CD40 ligand mAb treatment is sufficient to completely overcome CD4 cell-mediated resistance to allogeneic marrow engraftment and rapidly induce CD4 cell tolerance, but does not reliably overcome CD8 CTL-mediated alloresistance. The data suggest that costimulation, which activates alloreactive CTL, is insufficient to activate alloreactive CD4 cells when the CD40 pathway is blocked. The addition of host CD8 T cell depletion to anti-CD40 ligand treatment reliably allows the induction of mixed chimerism and donor-specific skin graft tolerance in 3 Gy-irradiated mice receiving fully MHC-mismatched bone marrow grafts. Thus, despite the existence of multiple costimulatory pathways and pathways of APC activation, our studies demonstrate an absolute dependence on CD40-mediated events for CD4 cell-mediated rejection of allogeneic marrow. Exposure to donor bone marrow allows rapid tolerization of alloreactive CD4 cells when the CD40 pathway is blocked, leading to permanent marrow engraftment and intrathymic tolerization of T cells that develop subsequently.

Peripheral deletion after bone marrow transplantation with costimulatory blockade has features of both activation-induced cell death and passive cell death

Two major pathways of death of previously activated T cells have been described: activation-induced cell death can be triggered by restimulating activated T cells with high concentrations of Ag, is Fas-dependent, is not influenced by proteins of the Bcl family, and is blocked by cyclosporin A; in contrast, passive cell death is induced by the withdrawal of growth factors and activation stimuli, is Fas-independent, and is blocked by Bcl family proteins. We examined the role of these two forms of cell death in the peripheral deletion of donor-reactive host T cells after allogeneic bone marrow transplantation and costimulatory blockade with anti-CD154 plus CTLA4Ig in two murine models. The substantial decline in donor-reactive CD4 cells seen in wild-type recipients 1 wk after bone marrow transplantation with costimulatory blockade was largely inhibited in Fas-deficient recipients and in Bcl-x(L)-transgenic recipients. We observed these effects both in a model involving low-dose total body irradiation and a conventional dose of bone marrow, and in a radiation-free regimen using high-dose bone marrow transplantation. Furthermore, cyclosporin A did not completely block the deletion of donor-reactive CD4(+) T cells in recipients of bone marrow transplantation with costimulatory blockade. Thus, the deletion of donor-reactive T cells occurring early after bone marrow transplantation with costimulatory blockade has features of both activation-induced cell death and passive cell death. Furthermore, these in vivo data demonstrate for the first time the significance of in vitro results indicating that proteins of the Bcl family can prevent Fas-mediated apoptosis under certain circumstances.

Breast cancer and active and passive smoking: the role of the N-acetyltransferase 2 genotype

The association of breast cancer with passive and active smoking was investigated in slow and fast acetylators of aromatic amines in a Geneva, Switzerland, study in 1996-1997. A slow acetylator was homozygous for one, or heterozygous for two, of three N-acetyltransferase 2 (NAT2) polymorphisms determined on buccal cell DNA from 177 breast cancer cases and 170 age-matched, population controls. The reference group consisted of women never regularly exposed to active or passive smoke. Among premenopausal women, the odds ratios were homogeneous in slow and fast acetylators: 3.2 (95% confidence interval (CI): 1.2, 8.7) for passive smoking and 2.9 (95% CI: 1.1, 7.5) for active smoking. Among postmenopausal women, the odds ratios for fast acetylators were 11.6 (95% CI: 2.2, 62.2) for passive and 8.2 (95% CI: 1.4, 46.0) for active smoking; the corresponding effects were also apparent but less strong in slow acetylators. After the nonexposed and the passive smokers were grouped in a single reference category, active smoking was associated with postmenopausal breast cancer in slow acetylators (odds ratio (OR) = 2.5, 95% CI: 1.0, 6.2) but not in fast acetylators (OR = 1.3, 95% CI: 0.5, 3.3). Thus, the associations of both passive and active smoking with breast cancer appear stronger in fast than in slow NAT2 genotypes. Separating passive smokers from the nonexposed impacts on the inference about a possible NAT2-smoking interaction.

Allogeneic bone marrow transplantation with co-stimulatory blockade induces macrochimerism and tolerance without cytoreductive host treatment

Allogeneic bone marrow transplantation (in immunocompetent adults) has always required cytoreductive treatment of recipients with irradiation or cytotoxic drugs to achieve lasting engraftment at levels detectable by non-PCR-based techniques ('macrochimerism' or 'mixed chimerism'). Only syngeneic marrow engraftment at such levels has been achieved in unconditioned hosts. This requirement for potentially toxic myelosuppressive host pre-conditioning has precluded the clinical use of allogeneic bone marrow transplantation for many indications other than malignancies, including tolerance induction. We demonstrate here that treatment of naive mice with a high dose of fully major histocompatibility complex-mismatched allogeneic bone marrow, followed by one injection each of monoclonal antibody against CD154 and cytotoxic T-lymphocyte antigen 4 immunoglobulin, resulted in multi-lineage hematopoietic macrochimerism (of about 15%) that persisted for up to 34 weeks. Long-term chimeras developed donor-specific tolerance (donor skin graft survival of more than 145 days) and demonstrated ongoing intrathymic deletion of donor-reactive T cells. A protocol of high-dose bone marrow transplantation and co-stimulatory blockade can thus achieve allogeneic bone marrow engraftment without cytoreduction or T-cell depletion of the host, and eliminates a principal barrier to the more widespread use of allogeneic bone marrow transplantation. Although efforts have been made to minimize host pre-treatment for allogeneic bone marrow transplantation for tolerance induction, so far none have succeeded in eliminating pre-treatment completely. Our demonstration that this can be achieved provides the rationale for a safe approach for inducing robust transplantation tolerance in large animals and humans.

Genetic variability in the diapause response of the burnet moth Zygaena trifolii (Lepidoptera: Zygaenidae)

A high degree of phenotypic variability was observed in the diapause response of the burnet moth Zygaena trifolii. In this study, we show that the observed variability is partly based on genetic differences between individuals. In a selection experiment, the larval instar at which diapause occurs was changed within six generations. Diapause instars were dependent on the time of pre-diapause development of larvae, which varied considerably between larvae. A heritability analysis indicates that a part of the variability in development time is based on additive genetic variance. The maintenance of genetic variability in the development time and the diapause response of Z. trifolii is discussed in the context of spatially and temporally changing selection pressures.

Gender differences and individual variation in the immune system of the scorpionfly Panorpa vulgaris (Insecta: Mecoptera)

From investigations of the vertebrate immune system gender specific differences in individual immunocompetence are well known. In general, females seem to possess more powerful immune systems than males. In invertebrates, the situation is much less clear. Therefore, we investigated the immune system of an invertebrate species, the scorpionfly Panorpa vulgaris. We found a high degree of individual variation in both traits studied, the lysozyme-like antibacterial activity of hemolymph and the capacity for in vitro phagocytosis of artificial particles. These two immune traits were positively correlated. As expected, hemolymph derived from females had higher lysozyme-like activity and hemocytes from females phagocytosed more particles. The difference in phagocytosis was mainly based on higher total hemocyte counts and higher proportions of phagocytically active cells in females, while the average number of ingested particles per active phagocyte was not significantly different. The observed gender differences are discussed in the context of reproductive strategies and parasite-mediated sexual selection.