Short communication: Correlation of methane production, intensity, and yield with residual feed intake throughout lactation in Holstein cows.

The environmental impact of dairy production can be reduced in several ways, including increasing feed efficiency and reducing methane (CH4) emissions. There is no consensus on their relationship. This study aimed at estimating the correlations between residual feed intake (RFI) and CH4 emissions expressed in g/d methane production (MeP), g/kg of fat- and protein-corrected milk methane intensity (MeI), or g/kg of DM intake methane yield (MeY) throughout lactation. We collected CH4 data using GreenFeed devices from 107 Holstein cows, as well as production and intake phenotypes. RFI was predicted from DM intake, fat- and protein-corrected milk, BW, and body condition score. Five-trait random regression models were used to estimate the individual variance components of the CH4 and production traits, which were used to calculate the correlations between RFI and CH4 traits throughout lactation. We found positive correlations of RFI with MeP and MeI ranging from 0.05 to 0.47 throughout the lactation. Correlations between RFI and MeY are low and vary from positive to negative, ranging from -0.18 to 0.17. Both MeP and MeI are favorably correlated with RFI, as is MeY during the first half of lactation. These correlations are mostly favorable for genetic selection, but the confirmation of these results is needed with genetic correlations over a larger dataset.

Comparison of methane production, intensity, and yield throughout lactation in Holstein cows.

Genetic selection to reduce methane (CH4) emissions from dairy cows is an attractive means of reducing the impact of agricultural production on climate change. In this study, we investigated the feasibility of such an approach by characterizing the interactions between CH4 and several traits of interest in dairy cows. We measured CH4, dry matter intake (DMI), fat- and protein-corrected milk (FPCM), body weight (BW), and body condition score (BCS) from 107 first- and second-parity Holstein cows from December 2019 to November 2021. Methane emissions were measured using a GreenFeed device and expressed in terms of production (MeP, in g/d), yield (MeY, in g/kg DMI), and intensity (MeI, in g/kg FPCM). Because of the limited number of cows, only animal parameters were estimated. Both MeP and MeI were moderately repeatable (>0.45), whereas MeY presented low repeatability, especially in early lactation. Mid lactation was the most stable and representative period of CH4 emissions throughout lactation, with animal correlations above 0.9. The average animal correlations of MeP with DMI, FPCM, and BW were 0.62, 0.48, and 0.36, respectively. The MeI was negatively correlated with FCPM (<-0.5) and DMI (>-0.25), and positively correlated with BW and BCS. The MeY presented stable and weakly positive correlations with the 4 other traits throughout lactation, with the exception of slightly negative animal correlations with FPCM and DMI after the 35th week. The MeP, MeI, and MeY were positively correlated at all lactation stages and, assuming animal and genetic correlations do not strongly differ, selection on one trait should lead to improvements in all. Overall, selection for MeI is probably not optimal as its change would result more from CH4 dilution in increased milk yield than from real decrease in methane emission. Instead, MeY is related to rumen function and is only weakly associated with DMI, FPCM, BW, and BCS; it thus appears to be the most promising CH4 trait for selection, provided that this would not deteriorate feed efficiency and that a system of large-scale phenotyping is developed. The MeP is easier to measure and thus may represent an acceptable alternative, although care would need to be taken to avoid undesirable changes in FPCM and BW.

Association between body condition genomic values and feed intake, milk production, and body weight in French Holstein cows.

Body condition score (BCS) offers a good estimate of the amount of stored fat on the body, and its variations can be used as a proxy for energy balance. Many countries have implemented a genomic evaluation of BCS, including France, where estimated breeding values are based on an individual BCS determination during the first lactation. In this article, we investigate the degree to which this genomic estimated breeding value based on a single phenotype record per cow might reflect different profiles of body reserves throughout lactation and be used to predict, and perhaps limit, their mobilization during early lactation. We also investigate whether selection on BCS affects other traits. A data set including 686 lactations of 435 Holstein cows from 3 experimental farms not used in the reference population for genomic evaluation was used to estimate the effects of the BCS direct genomic value (iBCS) on BCS, body weight, feed intake, milk production, and fat and protein contents throughout the lactation period. For each trait, the model included different iBCS regressions and an effect of the direct genomic value of the trait itself when available. It thus appeared that cows with a positive iBCS always had a higher BCS than negative iBCS cows, whatever the lactation stage, and that this difference increased during the first 6 mo to reach a difference of 0.8 point. A similar effect was seen regarding body weight, but it was the opposite for milk production, with negative iBCS cows producing slightly more milk (difference of about 3% over lactation). Feed intake increased slightly faster at the beginning of lactation for cows with positive iBCS. Therefore, iBCS is a promising tool that could help to limit intense mobilization during early lactation. Should feed efficiency be included in the breeding goal, greater attention should be paid to BCS to avoid further body mobilization in early lactation.

Genome-wide association study for age at puberty and resumption of cyclicity in a crossbred dairy cattle population.

Fertility is of primary economic importance in dairy cattle and the most common reason for involuntary culling. However, standard fertility traits have very low heritability that renders genetic selection slow and difficult. In this study, we explored fertility from an endocrine standpoint. A total of 1,163 crossbred Holstein-Normande females in a 3-generation familial design were studied for progesterone level measured every 10 d to determine age at puberty (PUB) and commencement of postpartum luteal activity (CPLA). Genetic parameters were estimated using REML with WOMBAT software. The heritability estimates were 0.38 ± 0.10 and 0.16 ± 0.07 for PUB and CPLA, respectively. Moreover, the 2 traits were genetically correlated (0.45 ± 0.23), suggesting a partially common determinism. Because of the family structure, a linkage disequilibrium and linkage analysis approach was preferred over standard genome-wide association study to map genomic regions associated with these traits. Ten quantitative trait loci (QTL) were detected for PUB on chromosomes 1, 3, 11, 13, 14, 21, and 29, whereas 3 QTL were associated with CPLA on chromosomes 21 and 26. Only the QTL on chromosome 21 was common to both traits. Four functional candidate genes (NCOA2, GAS2, OVOL1, and FOSL1) were identified in the detected regions. These findings will contribute to a clearer understanding of fertility determinism and enhance the value of introducing endocrinological data in fertility studies.

Characterization of Holstein and Normande whole milk miRNomes highlights breed specificities.

The concept of milk as a healthy food has opened the way for studies on milk components, from nutrients to microRNAs, molecules with broad regulatory properties present in large quantities in milk. Characterization of these components has been performed in several species, such as humans and bovine, depending on the stages of lactation. Here, we have studied the variation in milk microRNA composition according to genetic background. Using high throughput sequencing, we have characterized and compared the milk miRNomes of Holstein and Normande cattle, dairy breeds with distinct milk production features, in order to highlight microRNAs that are essential for regulation of the lactation process. In Holstein and Normande milk, 2,038 and 2,030 microRNAs were identified, respectively, with 1,771 common microRNAs, of which 1,049 were annotated and 722 were predicted. The comparison of the milk miRNomes of two breeds allowed to highlight 182 microRNAs displaying significant differences in the abundance. They are involved in the regulation of lipid metabolism and mammary morphogenesis and development, which affects lactation. Our results provide new insights into the regulation of molecular mechanisms involved in milk production.

Genetic parameters of milk production traits in response to a short once-daily milking period in crossbred Holstein × Normande dairy cows.

Despite its potential utility for predicting cows' milk yield responses to once-daily milking (ODM), the genetic basis of cow milk trait responses to ODM has been scarcely if ever described in the literature, especially for short ODM periods. This study set out to (1) estimate the genetic determinism of milk yield and composition during a 3-wk ODM period, (2) estimate the genetic determinism of milk yield responses (i.e., milk yield loss upon switching cows to ODM and milk yield recovery upon switching them back to twice-daily milking; TDM), and (3) seek predictors of milk yield responses to ODM, in particular using the first day of ODM. Our trial used 430 crossbred Holstein × Normande cows and comprised 3 successive periods: 1 wk of TDM (control), 3 wk of ODM, and 2 wk of TDM. Implementing ODM for 3 wk reduced milk yield by 27.5% on average, and after resuming TDM cows recovered on average 57% of the milk lost. Heritability estimates in the TDM control period and 3-wk ODM period were, respectively, 0.41 and 0.35 for milk yield, 0.66 and 0.61 for milk fat content, 0.60 and 0.80 for milk protein content, 0.66 and 0.36 for milk lactose content, and 0.20 and 0.15 for milk somatic cell score content. Milk yield and composition during 3-wk ODM and TDM periods were genetically close (within-trait genetic correlations between experimental periods all exceeding 0.80) but were genetically closer within the same milking frequency. Heritabilities of milk yield loss observed upon switching cows to ODM (0.39 and 0.34 for milk yield loss in kg/d and %, respectively) were moderate and similar to milk yield heritabilities. Milk yield recovery (kg/d) upon resuming TDM was a trait of high heritability (0.63). Because they are easy to measure, TDM milk yield and composition and milk yield responses on the first day of ODM were investigated as predictors of milk yield responses to a 3-wk ODM to easily detect animals that are well adapted to ODM. Twice-daily milking milk yield and composition were found to be partly genetically correlated with milk yield responses but not closely enough for practical application. With genetic correlations of 0.98 and 0.96 with 3-wk ODM milk yield losses (in kg/d and %, respectively), milk yield losses on the first day of ODM proved to be more accurate in predicting milk yield responses on longer term ODM than TDM milk yield.

Rapid Discovery of De Novo Deleterious Mutations in Cattle Enhances the Value of Livestock as Model Species.

In humans, the clinical and molecular characterization of sporadic syndromes is often hindered by the small number of patients and the difficulty in developing animal models for severe dominant conditions. Here we show that the availability of large data sets of whole-genome sequences, high-density SNP chip genotypes and extensive recording of phenotype offers an unprecedented opportunity to quickly dissect the genetic architecture of severe dominant conditions in livestock. We report on the identification of seven dominant de novo mutations in CHD7, COL1A1, COL2A1, COPA, and MITF and exploit the structure of cattle populations to describe their clinical consequences and map modifier loci. Moreover, we demonstrate that the emergence of recessive genetic defects can be monitored by detecting de novo deleterious mutations in the genome of bulls used for artificial insemination. These results demonstrate the attractiveness of cattle as a model species in the post genomic era, particularly to confirm the genetic aetiology of isolated clinical case reports in humans.

Effects of DGAT1 K232A polymorphism and milking frequency on milk composition and spontaneous lipolysis in dairy cows.

Milk spontaneous lipolysis (SL) of milk triglycerides is induced by the lipoprotein lipase, a milk native enzyme, and leads to an accumulation of partial glycerides and free fatty acids that are responsible for the deterioration of the taste of milk products. The gene coding for diacylglycerol acyltransferase 1 (DGAT1), an enzyme implicated in triglycerides synthesis, has an important polymorphic site at the K232A locus. This gene is well known to modulate milk composition. No data are available on the effects of DGAT1 on SL. Thus, a trial was carried out to evaluate the effects of DGAT1 K232A polymorphism on milk SL upon milking frequency variations [once- (ODM) and twice-daily milking (TDM)]. Twenty-one cows were divided into 3 groups according their DGAT1 K232A genotype: 8 cows had the KK genotype of DGAT1 (KK cows), 8 had the KA genotype (KA cows), and 5 had the AA genotype (AA cows). The trial consisted in 3 successive periods: 3 wk of TDM, 3 of ODM, and 4 of TDM. Samples were collected for fat and protein contents, SL, fatty acid, and protein profiles determinations. The KK cows presented higher fat and protein contents, lower milk production, and higher κ-casein percentage. No significant difference in fatty acid composition was noted between groups. The SL was twice as high for KK cows in TDM situations (1.13 vs. 0.59 and 0.63mEq/100g of fat, respectively, for KK, KA, and AA cows during the first period of TDM, and 0.46 vs. 0.25 and 0.21mEq/100g of fat, respectively, for KK, KA, and AA during the second period of TDM). The SL remained lower in TDM2 than in TDM1. During ODM, no difference in SL was found between groups and SL remained below 0.2mEq/100g of fat. These results demonstrate the existence of a correlation between DGAT1 genotypes and spontaneous lipolysis, in interaction with an environmental factor, milking frequency, although it has not been possible to clarify the causal mechanism at this stage.

Prediction of fatty acid profiles in cow, ewe, and goat milk by mid-infrared spectrometry.

Mid-infrared (MIR) spectrometry was used to estimate the fatty acid (FA) composition in cow, ewe, and goat milk. The objectives were to compare different statistical approaches with wavelength selection to predict the milk FA composition from MIR spectra, and to develop equations for FA in cow, goat, and ewe milk. In total, a set of 349 cow milk samples, 200 ewe milk samples, and 332 goat milk samples were both analyzed by MIR and by gas chromatography, the reference method. A broad FA variability was ensured by using milk from different breeds and feeding systems. The methods studied were partial least squares regression (PLS), first-derivative pretreatment + PLS, genetic algorithm + PLS, wavelets + PLS, least absolute shrinkage and selection operator method (LASSO), and elastic net. The best results were obtained with PLS, genetic algorithm + PLS and first derivative + PLS. The residual standard deviation and the coefficient of determination in external validation were used to characterize the equations and to retain the best for each FA in each species. In all cases, the predictions were of better quality for FA found at medium to high concentrations (i.e., for saturated FA and some monounsaturated FA with a coefficient of determination in external validation >0.90). The conversion of the FA expressed in grams per 100mL of milk to grams per 100g of FA was possible with a small loss of accuracy for some FA.

Ovariectomy improves lactation persistency in dairy cows.

A current trend in the dairy industry is to reduce milk yield at the peak of lactation and improve lactation persistency. Lactation persistency is influenced by livestock management factors, such as feeding level or milking frequency, or by physiological status, including reproductive status or calving period. These factors modulate mammary gland apoptosis and tissue remodeling, which determine the rate of decline of milk yield after the lactation peak. Previous studies on lactating cows suggested that ovarian steroids have a negative effect on milk yield after the peak of lactation. In the present study, 4 Holstein × Normande crossbred multiparous cows were ovariectomized at the time of the lactation peak, and 5 cows underwent sham operations. All of the cows were maintained in lactation for 14 mo and milk yield was recorded daily. At slaughter, mammary epithelial cell apoptosis and mammary tissue remodeling were assessed. Ovariectomized cows had improved lactation persistency and presented an average daily milk gain of 2.5 kg compared with the sham-operated cows between mo 6 and 14 of lactation. The ovariectomy appears to have limited the decline in the milk yield after the peak of lactation by reducing mammary epithelial cell apoptosis [by reducing poly(adenosine diphosphate-ribose) polymerase expression] and mammary-tissue remodeling (by reducing matrix metalloproteinase activity). In conclusion, removal of ovarian secretion via ovariectomy improved the cows' lactation persistency.

Effects of nutrient restriction on mammary cell turnover and mammary gland remodeling in lactating dairy cows.

The aim of this study was to investigate the effects of a severe nutrient restriction on mammary tissue morphology and remodeling, mammary epithelial cell (MEC) turnover and activity, and hormonal status in lactating dairy cows. We used 16 Holstein × Normande crossbred dairy cows, divided into 2 groups submitted to different feeding levels (basal and restricted) from 2 wk before calving to wk 11 postpartum. Restricted-diet cows had lower 11-wk average daily milk yield from calving to slaughter than did basal-diet cows (20.5 vs. 33.5 kg/d). Feed restriction decreased milk fat, protein, and lactose yields. Restriction also led to lower plasma insulin-like growth factor 1 and higher growth hormone concentrations. Restricted-diet cows had lighter mammary glands than did basal-diet cows. The total amount of DNA in the mammary gland and the size of the mammary acini were smaller in the restricted-diet group. Feed restriction had no significant effect on MEC proliferation at the time of slaughter but led to a higher level of apoptosis in the mammary gland. Gelatin zymography highlighted remodeling of the mammary extracellular matrix in restricted-diet cows. Udders from restricted-diet cows showed lower transcript expression of α-lactalbumin and kappa-casein. In conclusion, nutrient restriction resulted in lower milk yield in lactating dairy cows, partly due to modulation of MEC activity and a lower number of mammary cells. An association was found between feed restriction-induced changes in the growth hormone-insulin-like growth factor-1 axis and mammary epithelial cell dynamics.

[Dynamic studies of Langerhans cell histiocytosis cells. Their contribution to the current concept of the disease. Report of a series of 38 cases]. / Etudes dynamiques des cellules de l'histiocytose Langerhansienne. Leur apport dans le concept actuel de la maladie. A propos d'une série de 38 observations.

In vitro explantation of 38 fragments of eosinophilic granuloma of bones was attempted. A satisfactory growth was obtained in nearly 90% of cases. This short-term culture maintained the ultrastructural characteristics and, to a lesser extent, the cytochemical features of the Langerhans cells, confirming the Langerhans cell origin of this cell proliferation. In addition, this procedure was able to demonstrate an immunodependent erythrophagocytosis (3/3) and a preferential fixation of labelled precursors (Glycerol, choline of lipid metabolism as well as labelled dopamine (2/2). All attempts to obtain a permanent cell line and graft to nude mice (even irradiated) failed. Under the in vitro conditions, the Langerhans cells do not divide up but can be readily identified up to 2 or 3 weeks. The contrast between the evident in vivo proliferation and the in vitro quiescent state suggests that some undetermined growth-factors targeted to the Langerhans cell system are missing in our commonly used culture media. The in vitro culture procedure could be of some help to their identification.

Regulation of TNF-alpha and IL-1 gene expression during TPA-induced differentiation of "Malignant histiocytosis" DEL cell line t(5;6) (q35:p21).

The production of TNF-alpha and IL-1 alpha and beta molecules has been shown to be associated with the proliferation and activation of cells of the monocyte/macrophage series, the intermediate steps in the synthesis of these molecules have been less investigated. Unstimulated and TPA stimulated DEL cells (a CD30-positive, t(5;6)(q35;p21) malignant histiocytosis cell line) were used to study the expression of TNF-alpha and IL-1 genes and to evaluate, by nuclear run-on assay and biological measurements, the control of their transcription and the level of protein production. To refine this analysis, the effects of cycloheximide and actinomycin D were also evaluated in this investigation. Following TPA stimulation, transcription of TNF-alpha (constitutively present) increased threefold as early as 30 mins and started decreasing by 24h. Cycloheximide superinduced the expression of TNF-alpha mRNA and, accordingly, the release of its protein. By contrast, transcription of IL-1 molecules appeared de novo and did not result in a biologically detectable protein. Measurements of RNA half line after actinomycin D indicated that TNF-a and IL-1 alpha mRNAs are not as stable as that of IL-1 beta. These results indicate that, despite their common synergistic activity, the transcriptional and post-transcriptional mechanisms regulating the synthesis of TNF-alpha and IL-1 alpha and IL-1 beta involve different pathways.

In vitro treatment with retinoids or the topoisomerase inhibitor, VP-16, evidences different functional apoptotic pathways in acute promyelocytic leukemic cells.

Understanding the mechanisms inherent to malignant cell eradication is a major determinant for cancer therapy. Recent data have demonstrated that apoptosis may be one of the mechanisms through which both cytotoxic and differentiating drugs may eliminate malignant cells. Treatment of acute promyelocytic leukemia (APL) by all-trans retinoic acid (ATRA) is the first model of differentiation therapy allowing achievement of more than 90% complete remission (CR). However, disease-free survival (DFS) is short if patients are not subsequently treated with chemotherapy. In order to address the question of APL cells' elimination during ATRA therapy, we studied phenotypic and molecular features of 14 APL cases relative to cell survival in primary culture in the presence or absence of ATRA. Compared to other acute myeloid leukemia (AML) subtypes, APL cells in short-term suspension culture present a better survival rate (P < 0.001). After incubation with ATRA, cell survival was not altered and was correlated with a concomitant absence of apoptosis, despite a significant decrease of the BcL-2 protein in APL differentiated cells. Indeed, after 6 days of culture, only 3 +/- 0.5% of APL cells exhibit morphological features of apoptosis after ATRA treatment compared to 30 +/- 5% in HL-60-treated cells. Treatment of APL cells with 9-cis RA, 13-cis RA or analogs of RAR alpha or RXR alpha also failed to induce apoptosis. Treatment of either APL or ATRA-differentiated APL cells with 40 microM etoposide resulted in DNA fragmentation and morphological changes characteristic of apoptosis in 23 +/- 5% cells after only 20 h of treatment and 68 +2- 3% after 48 h suggesting that other pathways of apoptosis are still functional in APL cells. Though these in vitro data cannot fully represent the mechanism of cell death and cell elimination in vivo, they clearly indicate that ATRA alone may not induce leukemic clone eradication by apoptosis correlating with the persistence of minimal residual disease and constant relapse after CR obtained with ATRA alone.

PML protein expression in hematopoietic and acute promyelocytic leukemia cells.

Acute promyelocytic leukemia (APL) is thought to be caused by the t(15,17) translocation that fuses the PML gene to that of the retinoic acid receptor alpha (RAR alpha) and generates a PML/RAR alpha fusion protein. Yet, paradoxically, APL cells are exquisitely sensitive to retinoic acid (RA), as they terminally differentiate upon RA exposure. In this report, we have examined the expression of PML and PML/RAR alpha in normal and APL cells. By immunofluorescence or immunocytochemistry, we show that PML has a speckled nuclear pattern of expression that contrasts with that of PML/RAR alpha (mostly a micropunctuated nuclear pattern or a cytoplasmic localization). The APL-derived cell line NB4 that expresses both the PML and PML/RAR alpha genes also shows the fine micropunctuated nuclear pattern, suggesting a dominant effect of the fusion protein over the localization of wild-type PML. RA treatment of NB4 cells or clones expressing PML/RAR alpha gradually leads to a PML pattern before apparent morphologic maturation. In 14 untreated APL patients, the PML-reactive proteins were cytoplasmic (by immunocytochemistry) or both cytoplasmic and nuclear with a micropunctuated pattern (by immunofluorescence). Strikingly, in 4 patients, after 1 to 2 weeks of RA therapy, the speckled nuclear PML pattern reappeared concomitant with the onset of differentiation. These results establish that fusion of PML to RAR alpha results in an altered localization of PML that is reverted upon RA treatment. This observation, which highlights the importance of PML, is likely to be a key to unravelling the molecular mechanism of both leukemogenesis and RA-induced differentiation of APL.

Modulation of c-myc, c-myb, c-fos, c-sis and c-fms proto-oncogene expression and of CSF-1 transcripts and protein by phorbol diester in human malignant histiocytosis DEL cell line with 5q 35 break point.

Following exposure to phorbol ester (TPA), DEL cell line, a human malignant histiocytosis (MH) cell line, is able to differentiate along a macrophage phenotype and thus it provides a suitable model for analyzing the sequential and differential gene expression associated with monocyte/macrophage differentiation. C-myc, c-myb, c-fos, c-sis and c-fms expression were determined by Northern analysis at various times following TPA treatment. The results showed that TPA down-modulated the constitutive expression of c-myc, c-myb, and c-fms, mRNA to low but still detectable levels. Conversely, TPA-induced differentiation resulted in transient appearance of c-fos, whereas no change in the level of c-sis and actin transcripts were observed. Thus, the c-fms and c-sis genes appear to be regulated in a specific manner in this malignant histiocytosis derived cell line. Furthermore, these investigations demonstrated a constitutive CSF-1 gene expression which transiently increased at mRNA and also at protein level as evaluated by a murine bone marrow CFU bioassay. Through this drug-induced modulation, the DEL cell line offers an additional model for studying some of the subtle interrelations existing between a growth factor (CSF-1) and its receptor (c-fms) in the monocyte/macrophage system.

Malignant histiocytosis in childhood: a distinctive CD30-positive clinicopathological entity associated with a chromosomal translocation involving 5q35.

The clinicopathological data on 20 cases of malignant histiocytosis (MH) collected over a period of 30 years at the Hôpital des Enfants Malades (Paris) are reported. Childhood MH was characterized by disseminated, frequently tender lymphadenopathy (19/20), skin (8/20), bone (6/20), and soft tissue localizations (7/20). These features were usually accompanied by fever, deterioration of general condition, and hematological abnormalities including anemia, thrombocytopenia, and occasionally fibrinopenia. These manifestations were clinically suggestive of a diagnosis of a severe neoplastic blood disease, although this hypothesis was not entertained for a long time because of the initial absence of abnormal cells in the blood and bone marrow. MH was characterized by the proliferation of large "histiocyte-like," usually mononucleated cells. When suitable material was available, MH cells appeared to react positively with acid-phosphatase, alpha-naphthyl acetate esterase (ANAE), alpha-antichymotrypsin, and antibodies directed against EMA, HLA DR, CD25, CD30, CD68, and CD71. No B- and T-cell antigens (except for one case) have been detected. Due to the frequent abundance of accompanying granulocytes, lymphoid, and plasma cells, and the presence of areas of necrosis, an initial correct diagnosis of MH was often difficult to establish on skin (four cases), bone (two), and soft tissue (three) biopsies. In lymph nodes, the sinusoidal and perifollicular topography of cell proliferation represented a highly reliable morphological feature. A permanent cell line (DEL) was obtained from a pleural effusion showing a t(5;6)(q35;p21) translocation and a monoallelic immunoglobulin (IgjH) rearrangement and consistent levels of expression of c-fms, c-myc, c-myb, c-ki-ras and c-fgr. Since an identical 5q35 breakpoint has been reported in four other MH cell lines with a comparable phenotype and in several isolated published cases, this chromosomal abnormality provides a highly valuable argument for individualizing an authentic malignancy of the mononuclear phagocyte system (MPS) in childhood, among the rather heterogeneous group of the CD30+ anaplastic large cell lymphomas.

Human malignant histiocytosis CD30+ DEL cell line differentiates into macrophage-like cells when treated with a phorbol diester.

The histiocytic or lymphoid origin of human malignant histiocytosis is currently a subject of debate. The aim of this study was to investigate the in vitro effects of 12-O-tetradecanoylphorbol-13-acetate used as a differentiation inducer on the CD30, t(5;6)(q35;p21) DEL cell line, taken to be a reliable representative of the human malignant histiocytosis cell line. Treatment of DEL cells with 33 nM 12-O-tetradecanoylphorbol-13-acetate for 6-24 h resulted in cell surface attachment (up to 80%), decrease in dividing ability, enhancement of nitro blue tetrazolium reducing capacity (from 8 to 42%), occurrence of a limited immunodependent phagocytosis, and transient increase in expression of tumor necrosis factor alpha gene and in production of tumor necrosis factor alpha protein, whereas tumor necrosis factor beta remained undetectable. From these data, we can conclude that the malignant histiocytosis DEL cell line is not of lymphoid origin but stems from a myelomonocyte lineage.

Genotype markers and proto-oncogene analysis in the CD30-positive "malignant histiocytosis" DEL cell line with t(5;6)(q35;p21).

The DEL cell line isolated from a patient who died of malignant histiocytosis exhibits a reciprocal chromosomal translocation t(5;6)(5q35;6p21). The cells were analyzed for Ig(Jh), TCR beta-gene rearrangements and proto-oncogene expression pattern, using a panel of molecularly cloned probes that included c-fms, c-myc, c-myb, c-pim, c-fos, N-myc, c-sis, c-fgr as well as the virally derived probes v-ki-ras and v-src. Consistent levels of expression of c-fms, c-myc, c-myb, c-ki-ras and c-fgr were identified in cells from several in vitro passages as well as from the heterotransplanted tumors in nude mice. Transcripts homologous to the c-fos, c-src and c-sis were not observed. Southern blot study of DNA showed that the banding pattern of the screened proto-oncogenes was not altered. Furthermore, Southern blot analysis demonstrated monoallelic immunoglobulin heavy chain (IgJh) rearrangement but a normal germ-line configuration of the kappa light chain and TCR beta-genes. These results appear to imply that a T- or B-cell origin can be eliminated and that several activated proto-oncogenes, usually expressed in immature MPS cells (c-fms) and myeloblastic cells (c-fgr), may be implicated in the proliferative activity of the DEL cell line, the stem of which may be a primitive, ancestral myelomonocytic cell.

DEL cell line: a "malignant histiocytosis" CD30+ t(5;6)(q35;p21) cell line.

A new cell line DEL, established in vitro, was isolated from a pleural effusion of a boy who died of malignant histiocytosis. Its principal characteristics are: strong positivity with monoclonal antibodies (MAbs) to CD25, CD30, CD45R, KiM7, EMA, HLA Cl I and II; constant presence of acid phosphatase, ANAE, alpha-anti-trypsin, alpha-anti-chymotrypsin and NBT reductase activity; rearrangement of the immunoglobulin heavy-chain gene (JH) and a germ-line configuration of the T-chain gene; and finally a translocation between chromosomes 5-6 with a breakpoint in 5q35. The DEL cell line is appropriate for studying the role of the 5q localized c-fms oncogene and of the genes of the mononuclear phagocyte growth factor (CSFI) and of their receptors in the dynamics and etiology of malignant hemopathies associated with a 5q35 breakpoint.