Impact of the line of treatment on progression-free survival in patients treated with T-DM1 for metastatic breast cancer

Background

Trastuzumab emtansine (T-DM1) is indicated as second-line treatment for human epidermal growth factor receptor 2 (HER2)-positive metastatic or unresectable locally advanced breast cancer, after progression on trastuzumab and a taxane-based chemotherapy.

We wished to determine if the line of treatment in which T-DM1 is administered has an impact on progression-free survival (PFS) and in particular, if prior treatment with capecitabine/lapatinib or pertuzumab modifies PFS of further treatment with T-DM1.

Patients and methods

We performed a multicenter retrospective study in 3 Belgian institutions. We evaluated PFS with T-DM1 in patients treated for HER2 positive metastatic or locally advanced unresectable breast cancer between January 1, 2009 and December 31, 2016.

Results

We included 51 patients. The median PFS was 9.01 months. The line of treatment in which T-DM1 (1st line, 2nd line, 3rd line or 4+ lines) was administered had no influence on PFS (hazard ratio 0.979, CI95: 0.835–1.143).

There was no significant difference in PFS whether or not patients had received prior treatment with capecitabine/lapatinib (9.17 vs 5.56 months, p-value 0.875).

But, patients who received pertuzumab before T-DM1 tended to exhibit a shorter PFS (3.55 months for T-DM1 after pertuzumab vs 9.50 months for T-DM1 without pretreatment with pertuzumab), even if this difference was not statistically significant (p-value 0.144).

Conclusion

Unlike with conventional chemotherapy, the line of treatment in which T-DM1 is administered does not influence PFS in our cohort of patients with advanced HER2-positive breast cancer.

Sustainable laser-based technology for insect pest control

Aphids damage directly or indirectly cultures by feeding and spreading diseases, leading to huge economical losses. So far, only the use of pesticides can mitigate their impact, causing severe health and environmental issues. Hence, innovative eco-friendly and low-cost solutions must be promoted apart from chemical control. Here, we have investigated the use of laser radiation as a reliable solution. We have analyzed the lethal dose required to kill 90% of a population for two major pest aphid species (Acyrthosiphon pisum and Rhopalosiphum padi). We showed that irradiating insects at an early stage (one-day old nymph) is crucial to lower the lethal dose without affecting plant growth and health. The laser is mostly lethal, but it can also cause insect stunting and a reduction of survivors' fecundity. Nevertheless, we did not notice any significant visible effect on the offspring of the surviving irradiated generation. The estimated energy cost and the harmless effect of laser radiation on host plants show that this physics-based strategy can be a promising alternative to chemical pesticides.

Non-human primates use combined rules when deciding under ambiguity

Decision outcomes in unpredictable environments may not have exact known probabilities. Yet the predictability level of outcomes matters in decisions, and animals, including humans, generally avoid ambiguous options. Managing ambiguity may be more challenging and requires stronger cognitive skills than decision-making under risk, where decisions involve known probabilities. Here we compare decision-making in capuchins, macaques, orangutans, gorillas, chimpanzees and bonobos in risky and ambiguous contexts. Subjects were shown lotteries (a tray of potential rewards, some large, some small) and could gamble a medium-sized food item to obtain one of the displayed rewards. The odds of winning and losing varied and were accessible in the risky context (all rewards were visible) or partially available in the ambiguous context (some rewards were covered). In the latter case, the level of information varied from fully ambiguous (individuals could not guess what was under the covers) to predictable (individuals could guess). None of the species avoided gambling in ambiguous lotteries and gambling rates were high if at least two large rewards were visible. Capuchins and bonobos ignored the covered items and gorillas and macaques took the presence of potential rewards into account, but only chimpanzees and orangutans could consistently build correct expectations about the size of the covered rewards. Chimpanzees and orangutans combined decision rules according to the number of large visible rewards and the level of predictability, a process resembling conditional probabilities assessment in humans. Despite a low sample size, this is the first evidence in non-human primates that a combination of several rules can underlie choices made in an unpredictable environment. Our finding that non-human primates can deal with the uncertainty of an outcome when exchanging one food item for another is a key element to the understanding of the evolutionary origins of economic behaviour. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

Abstract P6-17-32: Impact of the line of treatment on progression-free survival in patients treated with T-DM1 for metastatic breast cancer

Background Trastuzumab emtansine (T-DM1) is a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2) receptors, conjugated with a cytotoxic component (a microtubule inhibitor). It is indicated as second-line treatment for HER2-positive metastatic or unresectable locally advanced breast cancer, after progression on trastuzumab and a taxane-based chemotherapy.

In HER2-negative metastatic breast cancer, progression-free survival (PFS) declines with each line of therapy, while patients with HER2-positive disease receive the most lines of chemotherapy and the longest duration for every line. We wished to investigate whether the line of treatment in which T-DM1 is administered has an impact on PFS. We also wished to explore whether prior treatment with capecitabine / lapatinib or pertuzumab had an impact on PFS, as none of the patients included in the registration trial had received these treatments before their inclusion in the trial.

Methods This is a multicenter retrospective study performed in 3 Belgian institutions. All patients received T-DM1 for HER2 positive metastatic or unresectable locally advanced breast cancer. The primary outcome was PFS with T-DM1, defined as the period between the first administration of T-DM1 and the first radiological or clinical assessment demonstrating progression of the disease.

Results We included 51 patients. One patient had to be excluded from the analyses because she no longer had HER positive disease. The median PFS was 9.01 months. The line of treatment in which T-DM1 was administered had no influence on PFS (hazard ratio 0.976, CI95 0.835-1.142).

There was no statistically significant difference in PFS between patients who had not received capecitabine / lapatinib before T-DM1 and those who had (9.11 vs 8.91 months, p-value 0.466).

Median PFS was 10.07 months when T-DM1 was administered prior to pertuzumab, and 5 months when administered after pertuzumab. Patients who received pertuzumab before T-DM1 thus tended to exhibit a shorter PFS. However, this difference is not statistically significant (p-value 0.096).

Conclusions Unlike with conventional chemotherapy, the line of treatment in which T-DM1 is administered does not influence PFS in metastatic breast cancer patients.

Citation Format: Duhoux FP, Dufour V, van Maanen A, Berliere M, Taylor D, Canon J-L. Impact of the line of treatment on progression-free survival in patients treated with T-DM1 for metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-32.

HPA-5 typing discrepancy reveals an Ile503Leu substitution in platelet GPIa (α2 integrin)

BACKGROUND AND OBJECTIVES

In fetal/neonatal thrombocytopenia, maternal alloimmunization is diagnosed by the identification of the maternal alloantibody and the offending paternal antigen inherited by the foetus/neonate. Today, for practical reasons, most laboratories perform platelet genotyping instead of phenotyping. Here, we report the case of a human platelet antigen (HPA)-5 genotype/phenotype discrepancy observed in a mother who delivered a mildly thrombocytopenic newborn.

MATERIALS AND METHODS

Platelet antibody detection and platelet phenotyping were performed using the MAIPA assay; platelet genotypes were determined using BeadChip technology (BioArray), PCR-SSP, PCR-RFLP and sequencing.

RESULTS

Serological investigations revealed the presence of maternal anti-GPIIbIIIa autoantibodies. No alloantibodies were detected. No feto-maternal platelet incompatibility was observed for HPA-1 to -21. The mother and newborn were genotyped as HPA-5aa using BeadChips, but as HPA-5a (weak b) with PCR-SSP and HPA-5ab with PCR-RFLP. Mother's platelets were phenotyped as HPA-5b(+). GPIa exon 13 sequencing confirmed the HPA-5ab genotype of the mother and newborn, and revealed an NM_002203.3:c.1594A>C mutation near the HPA-5 polymorphism (5' side), leading to an I503L amino acid change.

CONCLUSION

Feto-maternal alloimmunization was ruled out: the neonatal thrombocytopenia probably resulted from maternal anti-GPIIbIIIa autoantibodies. This case highlights that platelet typing should be performed using two different methods to avoid false diagnosis.

[Rotavirus vaccination in 2012. Position of the Pediatric Infections Pathology Group (GPIP) and the French Association of Ambulatory Pediatrics (AFPA)]

In 2008 and 2010, the Comité technique des vaccinations and the Haut Conseil de Santé Publique have not recommended generalized vaccination against rotavirus (RV) in France. The Groupe de Pathologie Infectieuse Pédiatrique (GPIP) and the Association Française de Pédiatrie Ambulatoire (AFPA) believes that it is time to reconsider the recommendation. Indeed, on the one hand, answers were made on the presence of circovirus in vaccines and the risk of intussusception, on the other hand, these vaccines are already implemented in vaccination programs in many developing countries or countries with income intermediate and high. Finally, independent studies have demonstrated the effectiveness in countries with widespread vaccinations (without significant genotypic changes of circulating strains). In addition, implementation would have a major impact on our health care system, changes of the epidemic curve of RV infections (delayed and shortened) to prevent the coexistence of different epidemics occurring during the fall and winter. Remains medico-economic evaluation, which is not of the competence and the responsibility of GPIP and AFPA. However, it seems surprising that developing or middle-income countries have been able to generalize this vaccination and that France can't do it.

[Current events in vaccination]

The annual meeting of the Infectious Disease Society of America (IDSA) ; which brought together nearly 5000 participants from over 80 countries in Vancouver, Canada, October 21 to 24, 2010 ; provided a review of the influenza (H1N1) 2009 pandemic, evaluated vaccination programmes and presented new vaccines under development. With 12,500 deaths in the United States in 2009-2010, the influenza (H1N1) 2009 pandemic was actually less deadly than the seasonal flu. But it essentially hit the young, and the toll calculated in years of life lost is high. The monovalent vaccines, whether live attenuated or inactivated with or without adjuvants, were well tolerated in toddlers, children, adults and pregnant women. In order to protect infants against pertussis, family members are urged to get their booster shots. The introduction of the 13-valent Pneumococcal conjugated vaccine in the beginning of 2010 may solve - but for how long ? - the problem of serotype replacement, responsible for the re-increasing incidence of invasive Pneumococcal infections observed in countries that had introduced the 7-valent vaccine. The efficacy of a rotavirus vaccine has been confirmed, with a reduction in hospitalization in the United States and a reduction in gastroenteritis-related deaths in Mexico. In the United States, vaccination of pre-adolescents against human papillomavirus (HPV) has not resulted in any specific undesirable effects. Routine vaccination against chicken pox, recommended since 1995, has not had an impact on the evolution of the incidence of shingles. Vaccination against shingles, recommended in the United States for subjects 60 years and over, shows an effectiveness of 55 %, according to a cohort study (Kaiser Permanente, Southern California). Although some propose the development of personalized vaccines according to individual genetic characteristics, the priority remains with increasing vaccine coverage, not only in infants but also in adults and the elderly. Vaccine calendars that cover a whole lifetime should be promoted, since the vaccination of adults and seniors is a determining factor of good health at all ages.

The impact of moving to a novel environment on social networks, activity and wellbeing in two new world primates

Among the stressors that can affect animal welfare in zoos, the immediate effect of relocation to a novel environment is one that has received little attention in the literature. Here, we compare the social network, daily activity and the expression of stress-related behavior in capuchins (Cebus apella) and squirrel monkeys (Saimiri sciureus) before and just after they were relocated to a new enriched enclosure. Results showed similar immediate responses to the move in the two species. Both showed a substantial increase in the time spent resting and spent more time in the highest and "safest" part of their enclosure after relocation. Both capuchins and squirrel monkeys spent significantly more time in close proximity to other group members after relocation, compared to before. In squirrel monkeys, the structure of the social network, which was initially correlated to affiliation, was no longer so after the move. In capuchins, the network analysis showed that individuals regrouped by age, with the youngsters who were potentially more affected by stress being in the center of the network. Social network analysis helped to achieve a more complete picture of how individuals were affected by relocation. We suggest that this type of analysis should be used alongside traditional methods of observation and analysis to encompass the most complex aspects of animal behavior in times of stress and to improve welfare.

Calculated reciprocity after all: computation behind token transfers in orang-utans

Transfers and services are frequent in the animal kingdom. However, there is no clear evidence in animals that such transactions are based on weighing costs and benefits when giving or returning favours and keeping track of them over time (i.e. calculated reciprocity). We tested two orang-utans (Pongo pygmaeus abelii) in a token-exchange paradigm, in which each individual could exchange a token for food with the experimenter but only after first obtaining the token from the other orang-utan. Each orang-utan possessed tokens valuable to their partner but useless to themselves. Both orang-utans actively transferred numerous tokens (mostly partner-valuable) to their partner. One of the orang-utans routinely used gestures to request tokens while the other complied with such requests. Although initially the transfers were biased in one direction, they became more balanced towards the end of the study. Indeed, data on the last three series produced evidence of reciprocity both between and within trials. We observed an increase in the number and complexity of exchanges and alternations. This study is the first experimental demonstration of the occurrence of direct transfers of goods based on calculated reciprocity in non-human-primates.

Effect of cheese consumption on emergence of antimicrobial resistance in the intestinal microflora induced by a short course of amoxicillin-clavulanic acid

AIM

To study in a sequential prospective trial, the effect of cheese consumption on the emergence of Escherichia coli and enterococci resistance to amoxicillin after amoxicillin-clavulanic acid (amoxiclav) treatment.

METHODS AND RESULTS

The study comprised two phases separated by 1 year. Each phase lasted 75 days for each volunteer (from day -13 to day 61). During the first phase, 18 healthy volunteers were given a 1-g dose of amoxiclav orally twice a day for 5 days (from day 0 to day 4). The design of phase 2 was identical to that of phase 1, except that the volunteers consumed 100 g of hard-cooked cheese from day -6 to day 19. Faecal samples were collected 20 times throughout the trial and were quantitatively assayed for total and amoxicillin-resistant (Amox(R)) E. coli and enterococci. The consumption of experimental cheese was associated with a decrease of Amox(R) enterococci during the post-antibiotic period, with the maximum level of Amox(R) enterococci falling from 6.2% to 0.03%. This effect was not observed for E. coli, and the type of cheese (raw milk vs pasteurized milk) did not influence the results.

CONCLUSIONS

Consumption of cheese during amoxiclav treatment reduces the emergence of Amox(R) enterococci in faeces. SIGNIFICANCE AND CLINICAL IMPACT OF THE STUDY: Our clinical pilot trial suggests that there are likely to be benefits from consuming probiotic-containing cheese during antibiotic treatment.

Enquête sur les effets secondaires locaux du vaccin intradermique BCG-SSI® chez l'enfant de moins de six ans en France

During April 2006, 579 physicians took part in a survey about intradermal BCG SSI adverse events (AE) in children less than 6 years old, managed by InfoVac France. Since January 2006, 68% physicians (paediatricians: 73% and general practitioners [GP]: 60%) have vaccinated at least one child. The site of injection is mainly the extern side of the shoulder (72%), according to the recommendations. Systematic vaccination is continued by 54% GP and 26% paediatricians. Others indications are: admission in day care center (33%), admission in day care center associated with risk factors (24%), or only risks factors (8%). Half physicians observed AE and 6% of them reported them at pharmacovigilance centers or pharmaceutical company. AE were mainly inflammations or indurations over 1 cm (for 75% of physicians who observed AE), oozing (73%). Abscesses are notified by 54%, ulcers by 39%, lymphadenopathies over 1 cm by 20%, suppurative lymphadenopathies by 3% and keloid scares by 17% of them, several AE may coexist for some children. Our aim is to start a prospective follow-up of BCG-SSI vaccination and its AE; 58% physicians who answered this investigation agreed to participate.

Chimpanzee (Pan troglodytes) anticipation of food return: Coping with waiting time in an exchange task

Despite controversial expectations that animals achieve reciprocal altruism, it is unclear if nonhuman species possess the necessary cognitive abilities. For reciprocal altruism, individuals must anticipate the loss of a commodity and accept a delay before some return. The authors investigated the abilities of 5 chimpanzees (Pan troglodytes) to cope with increasing waiting duration in exchange tasks. Subjects had to keep a small cookie before returning it to a human partner to obtain a larger piece. For a piece 2, 4, or 8 times the size of the small piece, 3 of the 5 subjects waited for up to 4 min. For a piece 40 times larger, 4 of the 5 subjects waited up to 8 min. At long time lag, renouncement to wait occurred earlier than predicted by subjects' general waiting capacity, suggesting that the decision to wait was based on a trade-off between reward quantity and expected costs of the waiting duration. Chimpanzees could anticipate a delayed reward at a time scale of several minutes. If this reflects a cognitive limit in chimpanzees' anticipation capacity, reciprocal altruism by keeping track of costs and benefits over extended periods may be unlikely in chimpanzees.

Imaging does not predict the clinical outcome of bacterial vertebral osteomyelitis

OBJECTIVES

Magnetic resonance imaging (MRI) and computed tomography (CT) are useful for initial assessment of bacterial spondylodiscitis. However, clinical relevance of imaging changes during treatment is less well-documented.

METHODS

Between October 1997 and March 2005, 29 patients with documented bacterial spondylodiscitis were prospectively enrolled. They had clinical, biological and imaging examinations (MRI and/or CT) at M0 and M3, and in 22 cases, at M6.

RESULTS

Mean age was 58 yrs. Antimicrobial chemotherapy lasted an average of 98 days. The median follow-up was 18 months, including 12 months after the completion of treatment. Infection was cured in every patient. Biological markers of inflammation returned to normal at M3. Six patients had painful and/or neurological sequelae. Decreased disc height was a consistent and early sign, and remained stable during the follow-up. Vertebral oedema, present in 100% of cases initially, persisted in 67 and 15% of cases at M3 and M6, respectively. Discal abscesses and paravertebral abscesses, present in 65 and 39% of cases initially, persisted in, respectively, 42 and 9% of cases at M3 and in 18 and 3% of cases at M6. Epidural abscesses were present at diagnosis in 30% of cases, and had always disappeared by M3. Imaging abnormalities found at M0 and M3 did not differ between patients with and without late neurological or painful sequelae.

CONCLUSIONS

Imaging abnormalities often persist in patients with bacterial spondylodiscitis despite a favourable clinical and biological response to antibiotic treatment. They are not associated with relapses, neurological sequelae or persistent pain. Imaging controls are not necessary when bacterial spondylodiscitis responds favourably to treatment.

Accepting loss: the temporal limits of reciprocity in brown capuchin monkeys

Delayed reciprocity is a potentially important mechanism for cooperation to occur. It is however rarely reported among animals, possibly because it requires special skills like the ability to plan a loss. We tested six brown capuchin monkeys (Cebus apella) in such skills. Subjects were studied in exchange tasks in which they had to retain a food item for a given time lag before returning it to an experimenter and obtaining a more desirable reward. Experiments showed that the subjects could wait for several minutes when allowed to return only part of the initial item. When required to return the full item intact, however, most subjects could not sustain a time lag longer than 10 s. Although the duration of waiting increased with the amount of return expected by subjects, in most cases it did not extend beyond 20 s even when the eperimenter offered a food amount 40 fold the initial item. The failure of capuchin monkeys to sustain long-lasting waiting periods may be explained by limited self-control abilities. This would prevent them achieving reciprocal altruism.

[Activities of parentality teams in Paris: patient demands and staff responses]

In application of public policy, parentality teams were created in Paris in June 1998. All ten maternity units of the Paris Hospital Group (AP-HP) participated in developing these teams but staff implications varied between the institutions. Other maternity units in Paris have also instituted parentality teams which are still operating. The Paris Maternal and Infantile Protection administration together with INSERM Unit 149 were charged with the evaluation of these teams. The first phase of "active monitoring" terminated 2001, and discussions between the different teams in October 2004 allowed an analysis of the current situation.

Two cases of cerebral aspergillosis successfully treated with voriconazole

Described here are two cases of cerebral aspergillosis successfully treated with voriconazole after the failure of first-line treatment with amphotericin B deoxycholate. In both cases, clinical and radiological cure was achieved within 6 weeks. Voriconazole should be considered as first-line therapy for cerebral aspergillosis.

Parasites of recruiting coral reef fish larvae in New Caledonia

Recruiting coral reef fish larvae from 38 species and 19 families from New Caledonia were examined for parasites. We found 13 parasite species (Platyhelminthes: Monogenea, Cestoda and Trematoda) but no acanthocephalan, crustacean or nematode parasites. Over 23% of individual fish were infected. Didymozoid metacercariae were the most abundant parasites. We conclude that most of the parasites are pelagic species that become 'lost' once the fish larvae have recruited to the reef. Larval coral reef fish probably contribute little to the dispersal of the parasites of the adult fish so that parasite dispersal is more difficult than that of the fish themselves.

Induction of porcine cytokine mRNA expression after DNA immunization and pseudorabies virus infection

Injection of plasmid DNA encoding pseudorabies virus (PRV) glycoprotein into pig muscle has been shown to result in protective immunity against lethal infection. Here, pigs were vaccinated by a single coinjection of three plasmids encoding PRV glycoproteins gB, gC, and gD, with plasmid expressing porcine granulocytemacrophage colony-stimulating factor (GM-CSF) or porcine interferon-alpha (IFN-alpha). DNA immunization induced a primary T cell-mediated response characterized by low rates of IFN-gamma, interleukin-2 (IL-2), and IL4 mRNA in peripheral blood mononuclear cells (PBMC). Very low rates of PRV-specific IgG1 and the absence of IgG2 were obtained. Codelivery of plasmid expressing GM-CSF or IFN-alpha had no effect on cytokine mRNA expression or on B cell response. After a high virulent challenge, high levels of cytokine mRNA, mainly IFN-gamma, and high secondary antibody (Ab) response were induced in all DNA-vaccinated pigs. Codelivery of GMCSF gene significantly increased both Th immune response (i.e., IFN-gamma and IL-4 mRNA expression) and clinical protection but had no effect on secondary B immune response. Codelivery of IFN-alpha gene had no beneficial effect on secondary T and B cell immune responses.

Endoparasite species richness of new caledonian butterfly fishes: host density and diet matter

Ecological factors may influence the number of parasites encountered and, thus, parasite species richness. These factors include diet, gregarity, conspecific and total host density, habitat, body size, vagility, and migration. One means of examining the influence of these factors on parasite species richness is through a comparative analysis of the parasites of different, but related, host species. In contrast to most comparative studies of parasite species richness of fish, which have been conducted by using data from the literature, the present study uses data obtained by the investigators. Coral reef fishes vary widely in the above ecological factors and are frequently parasitized by a diverse array of parasites. We, therefore, chose to investigate how the above ecological factors influence parasite species richness in coral reef fishes. We investigated the endoparasite species richness of 21 species of butterfly fishes (Chaetodontidae) of New Caledonia. We mapped the diet characters on the existing butterfly fish phylogeny and found that omnivory appears to be ancestral. We also mapped the estimated endoparasite species richness, coded from low to high parasite species richness, on the existing butterfly fish phylogeny and found that low parasite species richness appears to be associated with the ancestral state of omnivory. Different dietary and social strategies appear to have evolved more than once, with the exception of obligate coralivory, which appears to have evolved only once. Finally, after controlling for phylogenetic relationships, we found that only the percentage of plankton in the diet and conspecific host density were positively correlated with endoparasite species richness.

Quantification of porcine cytokine gene expression using RT-PCR, a homologous internal control and chemiluminescence for microplate detection

The polymerase chain reaction (PCR) has proved to be a sensitive and versatile method for the analysis of human and murine cytokine mRNA expression. This paper describes for the first time a reverse transcription-polymerase chain reaction (RT-PCR) at end-point for the quantification of five porcine cytokines: interferon (IFN)-gamma, interleukin (IL)-2, IL-4, IL-10 and IL-18. The main features of the methodology are: (1) a unique RT for all quantifications, (2) the addition of homologous DNA internal controls (IC) of equal length to the corresponding cytokine and consequently co-amplification of the target cytokine and the IC with equivalent efficacy, (3) PCR and detection of amplicons for all cytokines simultaneously, (4) cytokine quantification in relation to a housekeeping gene control (glyceraldehyde-3-phosphate dehydrogenase, GAPDH), (5) detection of the amplicons by enzyme linked immunosorbent assay (ELISA) using a chemiluminescent substrate with high sensitivity and wide dynamic range, (6) automation of the detection system for analysis of a large number of samples. This highly sensitive quantitative RT-PCR assay (able to detect 100-200 cytokines mRNA copies/75x10(3) cells) was validated on peripheral blood mononuclear cells (PBMC) from pigs infected or not with pseudorabies virus (PRV), re-stimulated in vitro by a mitogen or antigens.

Generation of diversity in mammalian gut-associated lymphoid tissues: restricted V gene usage does not preclude complex V gene organization

The sheep genome contains 60 to 90 V lambda genes distributed in least 6 different families, whereas 37 V lambda genes and 10 families exist in humans. Comparison with human V lamda sequences indicates that sheep V lambda genes display less overall sequence divergence, but are closer to the genes most frequently used in the human peripheral repertoire. In both species, 2 to 3 genes contribute half of the expressed sequences. Therefore, similar large combinatorial potential and restriction of the expressed repertoire can exist in two species whose strategy of diversification differs widely (ongoing rearrangement throughout life in human bone marrow vs postrearrangement diversification during early development in sheep ileal Peyer's patches).

Generation of diversity in mammalian gut-associated lymphoid tissues: restricted V gene usage does not preclude complex V gene organization

The sheep genome contains 60 to 90 V lambda genes distributed in least 6 different families, whereas 37 V lambda genes and 10 families exist in humans. Comparison with human V lamda sequences indicates that sheep V lambda genes display less overall sequence divergence, but are closer to the genes most frequently used in the human peripheral repertoire. In both species, 2 to 3 genes contribute half of the expressed sequences. Therefore, similar large combinatorial potential and restriction of the expressed repertoire can exist in two species whose strategy of diversification differs widely (ongoing rearrangement throughout life in human bone marrow vs postrearrangement diversification during early development in sheep ileal Peyer's patches).

Genomic organization of the sheep immunoglobulin JH segments and their contribution to heavy chain variable region diversity

The sheep immunoglobulin heavy chain Igh-J locus has been characterized in order to determine the genomic organization of JH segments and their contribution to heavy chain diversity. The locus contains six segments, of which two are functional and four are apparently pseudogenes. These segments span a 1.8 kilobase (kb) region. The distance between JH-ps4 (the 3'-most segment) and the first domain of the mu-chain encoding constant gene is about 5 kb. The two functional JH segments have a standard upstream recombination signal sequence, including heptamer and nonamer sequences separated by a 22-23 nucleotide spacer, and end with a RNA donor splice site. These two segments possess all the characteristic JH invariant residues and are found in expressed mu heavy chain variable regions. The 5' functional JH1 segment is used in more than 90% of the cDNAs sequenced to date. The contribution of JH segment germline multiplicity to variable regions diversity appears therefore to be minimal. Comparison with other mammalian JH segments shows that all loci are very closely related and probably have evolved from a common ancestral locus.

Parasites of coral reef fish recruits, Epinephelus merra (Serranidae), in French Polynesia

Honeycomb grouper recruits Epinephelus merra (Serranidae) from 2 recruitment events on Moorea Island, French Polynesia, were examined for internal parasites. Trypanorhynch blastocysts (Eucestoda: Trypanorhyncha) and encysted phyllobothriid metacestodes (Eucestoda: Phyllobothriidae) were found in recruits from both events. Fish from the second event were examined later as juveniles and were found to harbor apparently melanized parasites. Neither parasite was found in adults. Evidence suggests these patterns are not due to differential mortality among recruits but to the elimination of parasites by host immune responses. The data also suggest that pelagic fish larvae may represent a dispersal mechanism for parasites if transfer occurs before the death of the parasite.

The sheep Ig variable region repertoire consists of a single VH family

Nine germ-line Ig heavy chain variable (VH) segments (including three pseudogenes) were isolated from a genomic DNA library, and the other six were obtained by PCR, using 5'and 3' primers deduced from the first three. They appear to belong to a homogeneous VH gene family, with >80% sequence identity. This sheep VH gene family is related to the human VH4 family and to the murine VH1 subgroup (clan II). Southern blot analysis shows a maximum of 10 positive restriction fragments; therefore, the nine VH genes isolated probably constitute the major part of the repertoire. Thirty-one expressed mu variable regions (and one gamma 1 variable region) were obtained from adult spleen by either cDNA cloning or anchored reverse transcriptase-PCR; they are >80% similar to each other (in their leader to framework 3 regions) and to the germ-line sequences as well. The sheep VH repertoire thus seems to derive from a small (approximately 10 members) germ-line gene family, and its diversification must rely chiefly on junctional (D and/or N regions) diversity and somatic hypermutations.

The sheep Ig variable region repertoire consists of a single VH family

Nine germ-line Ig heavy chain variable (VH) segments (including three pseudogenes) were isolated from a genomic DNA library, and the other six were obtained by PCR, using 5'and 3' primers deduced from the first three. They appear to belong to a homogeneous VH gene family, with >80% sequence identity. This sheep VH gene family is related to the human VH4 family and to the murine VH1 subgroup (clan II). Southern blot analysis shows a maximum of 10 positive restriction fragments; therefore, the nine VH genes isolated probably constitute the major part of the repertoire. Thirty-one expressed mu variable regions (and one gamma 1 variable region) were obtained from adult spleen by either cDNA cloning or anchored reverse transcriptase-PCR; they are >80% similar to each other (in their leader to framework 3 regions) and to the germ-line sequences as well. The sheep VH repertoire thus seems to derive from a small (approximately 10 members) germ-line gene family, and its diversification must rely chiefly on junctional (D and/or N regions) diversity and somatic hypermutations.

Platelet production in idiopathic thrombocytopenic purpura

522 patients with chronic thrombocytopenia were studied over a period of three years. 252 of them suffered from idiopathic, acquired, thrombocytopenic purpura with excessive platelet destruction (platelet count less than 50,000 and mean survival less than 3 days). All of these cases were studied by using Indium oxinate labelled autologous platelets. The essential finding in these cases was the absent or only slight reactive hyperproduction, regardless of age and regardless of the severity of platelet destruction. No significant modification in platelet production was observed in the presence or in the absence of anti-platelet antibodies. No significant difference in the haematopoietic response, which was only exceptionally greater than twice the normal value, was observed whether thrombocytopenia was or not very long-standing, very severe, or affected a child or an adult. Megakaryocytosis, assessed on smears or biopsy sections, and the mean platelet volume do not constitute parameters for measuring platelet production. These findings confirm previous findings reported in the 1970s using radioactive chromium as the tracer. They demonstrate that the regulation of megakaryocyte production differs from that of erythropoietic production. They also show that determination of platelet production based on the survival of autologous platelets is able to distinguish between excessive destruction, even in the absence of a haematopoietic response, and defective production, demonstrated when the haematopoietic response is less than 50% of the normal value.

The site of platelet destruction in thrombocytopenic purpura as a predictive index of the efficacy of splenectomy

The significance of the site of platelet sequestration in determining the indication for splenectomy in idiopathic thrombocytopenic purpura (ITP) is a controversial subject. However, most of the negative conclusions are based on 51chromium labelling of homologous platelets. We report here the results of an analysis of 222 cases in which the kinetic study of 111indium-oxinate-labelled autologous platelets was performed under homogeneous technical conditions. 103 of these patients subsequently underwent splenectomy. This study demonstrates that the site of platelet sequestration in active ITP constitutes a variable independent of the patient's age, history of the disease and its severity (platelet count, lifespan). The sequestration site is a good predictive element of the short-term efficacy of splenectomy (71/76 cases with splenic sequestration obtained a platelet count exceeding 100 x 10(9)/l versus 7/13 cases with mixed sequestration and 1/14 cases with hepatic sequestration), and the long-term results (6 months to 5 years after splenectomy) do confirm the clinical value of this study.

Platelet kinetics in human immunodeficiency virus induced thrombocytopenia

A platelet kinetic study was performed in 34 patients (33 homosexuals and/or drug addicts) with (in most of them) severe and isolated thrombocytopenia and human immunodeficiency virus positive serological tests. The reported data indicate that the thrombocytopenia is due to an extracorpuscular hyperdestruction. The sequestration of the labeled platelets is exclusively splenic in most of the cases. Splenectomy was successful in the ten cases in which it was done; however, corticoids showed no or low effect, and Ig-G infusion had only a temporary efficacy.