00:00:01.120 Alan Gray here with the Microbiome First Summit underwritten by the World Asthma Foundation. We’re pleased to introduce
00:00:08.320 our next speaker, Dr. Patricia Machuiverie. Dr. Machuiverie is a clinical and translational researcher,
00:00:15.599 research fellow at the University of Western Australia and honorary research associate for Teleathon Kids Institute.
00:00:23.680 Dr. Makio’s research found that breast milk is a source of infant exposure to HTM allergen and derpy1 in breast milk
00:00:32.238 can act as an adgiant and increase the risk of food and respiratory allergy.
00:00:38.160 Today Dr. Mackiverie presents her session house dustmite shedding in human
00:00:43.600 milk a neglected cause of allergy susceptibility. Dr. Mackiverie over to you.
00:00:50.719 So hi everyone I would like to start. Thank you. the microbium for Smith for
00:00:55.840 the invitation. It’s a pleasure to be here today and thank you for the audience. We I really hope you enjoy the
00:01:04.080 time we spend together today and thank you Alan also for the all this
00:01:09.200 organization. So today I’m going to share with you some of the data and
00:01:15.360 important questions that have been guiding my research in the last years on how we can improve allerg
00:01:23.119 prevention through breastfeeding. So I would like to start talking about
00:01:28.240 the origins of health and disease. So it’s known that early life is a period
00:01:34.640 where let me put a point here uh where this infant is is deficient in
00:01:42.799 both main arms of the immune system. So theector immune response and heulatory
00:01:48.560 immune response. So it’s more susceptible to infectious disease and it’s also more susceptible
00:01:55.439 to disease like allergies. So it’s quite clear in western countries for example
00:02:00.560 here in Australia where the instance of allergy is really high that for example
00:02:05.680 here 10% of one year old infants have allergy.
00:02:10.800 So with time this developing infant will gain the ability to mount and then to
00:02:16.720 respond to a specific target and this ability is really uh the key for a
00:02:22.000 lifelong protection against infections and uninfectious diseases. Uh so early in early oops
00:02:30.640 sorry so the diet and environmental factors here early life are really key
00:02:36.879 players to guide uh this development of the immune system
00:02:43.840 in this regard uh breast milk uh it’s really important first because it’s the
00:02:50.080 physiological food for this uh baby and it’s also part of the baby’s
00:02:56.239 environment. So why uh so we know that breast milk composition it’s directly
00:03:02.640 related to maternal health, maternal diet and also maternal environment. So
00:03:07.680 through breast milk the mom will transfer to the baby accumulated knowledge about the environment she was
00:03:13.599 exposure to all her life and it’s important not only to a passive immune
00:03:21.280 uh protection to the baby as we all know this is the presence of specific antibodies but it’s also important to
00:03:29.760 shape and to actively uh shape this uh baby immune system.
00:03:37.280 So saying that looks quite obvious but sometimes we forget that we are malo so
00:03:42.560 we consider the infant um deficient immunity deficient but
00:03:49.120 physiologic it shouldn’t be considered efficient because it should be always be
00:03:55.120 complemented with those maternal immune factors through breast milk.
00:04:02.239 Okay. So the proof that breast milk is really complementing the baby immune
00:04:08.560 system uh is the the knowledge that we know that if we scaling up breastfeeding
00:04:15.920 to a nearly universal levels we can prevent about 1 million annual death in
00:04:21.358 children’s younger than five year. So it’s really the proof that breastfeeding
00:04:26.720 is the most powerful way to prevent infectious disease and we know that it’s
00:04:31.759 really good to prevent for example otitis, nia, diarrhea, hyper infections
00:04:37.120 and it’s also really good for non-infectious disease. For example, it
00:04:42.160 has been proven that it can improve the infant cognitive performance. However,
00:04:48.240 when we look to allergy prevention, the data is not that clear.
00:04:55.120 So although some individual studies have shown that breastfeeding can protect
00:05:00.960 from allergy, if we look to u the new guidelines, meta analysis and
00:05:08.960 systematic reviews uh they all conclude that are very limited data about that
00:05:15.199 and we can’t conclude that breastfeeding itself is protecting against allergy. if
00:05:21.840 we look to population. So that’s the question that uh I want to
00:05:31.280 understand and to answer is how we can then improve allergy prevention uh by
00:05:36.479 breastfeed. So we know that breast milk has a huge
00:05:43.280 potential to prevent allergy because we know that has a broad range of bioactive
00:05:49.680 compounds that will affect uh parameters that are important to allergy prevention. So mainly to induce oral
00:05:56.720 tolerance. Uh so we know there is the milk microbiota you know mucolic
00:06:02.240 saccharides and microbial molecules that are really important to seed and then to
00:06:07.520 shape the the gut microbiota in the baby factors like epileog factors that are
00:06:13.759 really important for health gut barrier. So that’s important for us and also
00:06:21.280 immological factors as cytoines and immunoglobins that will uh that has like
00:06:27.840 more anti-inflammatory properties and are important to shape uh the immune
00:06:33.440 differentiation in the in the baby. So there is a lot of research on how the
00:06:39.919 microbiota can uh help on allergy prevention and this Dr. Leaky wonder you
00:06:46.960 give a very nice talk about this here. Uh but there is not much data about how
00:06:54.400 the allergens in breast milk can then uh influence the allergic risk in the
00:07:00.560 breastfed infant. So we have been doing some research in that and this is what
00:07:05.919 I’m going to show you now. Uh so after uh a long time a long period
00:07:14.880 where the allerg avoidance uh was the recommendation to prevent allergy. Now
00:07:21.759 the new guidelines we recommend a early oral introduc to to allergens
00:07:28.720 and this is around four to six months of age and then to induce oral tolerance
00:07:34.960 and then prevent allergic sensitization. And this new guideline is based
00:07:40.720 mainly in the research and the data lack and his group showing that actually the
00:07:47.680 infant will be sensitized through the skin and if you have a delay in the
00:07:52.880 introduction of this food antigen through then they don’t induce oral
00:07:58.080 tolerance and then um the risk to allergy is higher. So this is uh well
00:08:07.199 demonstrated for peanut allergen although the protocol to introduce this
00:08:12.639 early life is quite hard to in in real life to to follow but there
00:08:19.680 is evidence for peanut but it’s limited for other allergens some evidence for egg but no for fish cold milk and wheat
00:08:27.440 for example that’s very common another problem is that some
00:08:33.679 infants 30% of infants they have already allergic sensation
00:08:39.519 at 3 months of age. So the first time they have they are introduced to the
00:08:45.360 allergy in this case egg they had already an athletic shock and there was incitance. So it means that we we need
00:08:54.160 to induce this oral tolerance really early in life before the introduction of
00:08:59.200 food and then we think that human milk can help on that.
00:09:05.040 So we want to know if it’s import if it’s possible to induce oral tolerance
00:09:11.279 if the allergen is transferred through breast milk in the presence of all those
00:09:17.279 uh regulatory factors that I’ve shown you before.
00:09:23.279 So it has been demonstrated that yeah if you have egg allergen given to the the
00:09:30.480 baby through breast milk you can induce uh oral tolerance and
00:09:37.040 then protect this um baby here in adult life in the case uh from allergic
00:09:44.160 asthma. Importantly the presence of egg itself is not sufficient to induce this
00:09:50.000 oral tolerance. you need the egg together with other factors that you have in breast milk for example digest
00:09:56.880 beta vitamin A complex to induce tolerance and
00:10:02.320 protection from allergic acid. So this study was published in 2008,
00:10:09.440 nature medicine by herself and more recently she
00:10:16.720 translated this data to a human cohort and indeed she proved that uh babies
00:10:24.240 that were breastfed by moms with egg in breast milk you they are they were at
00:10:31.360 lower risk for IG mediated egg allergen. So egging breast milk can really protect
00:10:37.440 from allergy. Uh so knowing that we can induce now if
00:10:47.680 you have egg in breath or allergy protection we wanted to know if it was
00:10:53.279 true also for respiratory allergen. So we choose house the smart because it’s
00:11:00.000 the this allergen is really common. you can find crowded almost everywhere and
00:11:05.920 all uh around the world and it has responsible for 50% of degrees of
00:11:12.880 respiratory allergies. So it’s a very common respiratory allergy.
00:11:20.560 So first we wanted to know if we could find houses might allergen in breast milk because so far any airborne
00:11:28.480 allergen had been detected. In a moment we know the presence of food allergens but not discriminatory allergies.
00:11:35.920 So the question the question the answer is yes we can find houses might impress
00:11:41.920 you. So we have now been analyzing uh for a
00:11:47.279 long time these allergens in breast milk and we had analyzed different cohorts.
00:11:53.040 So I combined everything here and you can find all the details in this review
00:11:58.640 here. Uh so we have analyzed samples from Brazil, France, Australia and the
00:12:05.920 Netherlands. So almost all continents and it’s amazing that we find
00:12:13.040 very similar u concentration of houses might allergen in breast milk. Uh so
00:12:20.000 it’s around 100 pogs per male and the
00:12:25.279 percentage of positive samples are really similar among different countries. So uh around
00:12:33.680 60% of the mouse uh will secrete houses might breast milk.
00:12:40.560 So uh if we compare this concentration to induction of like protein in breast
00:12:46.320 milk we that usually is in the range of milligrams per ml we may find that this
00:12:52.399 is really low and maybe not important poggrams per ml of houses might
00:12:57.920 allergen. But then if you look the level of egg that’s a very common food
00:13:03.279 allergen in breast milk we can see it’s present exactly in the same range.
00:13:10.240 So yes smite is present in breast milk and it’s in the same range as a food
00:13:16.560 allergen. So then we use an animal model to see if
00:13:22.959 we could protect the baby houses to breast milk and we use a animal model
00:13:29.839 that really mimics the human situation. So we give houses might to the lactating mother intraasally during the lactation
00:13:37.600 uh period three weeks and we don’t lose any of that.
00:13:43.600 However, um opposite of what we were expecting, uh when the the the
00:13:51.200 neonate receive house might through breast milk, it’s not protecting, but instead it’s priming for allergic
00:13:57.600 sensitization. So you can see here there is like fivefold increase in the levels
00:14:03.199 of der specific IGB and D specific IGT1.
00:14:08.480 So you induce allergic sensitization. Uh
00:14:13.920 then we investigate in a human cohort. So we had access to eden French birth
00:14:20.959 cohort where we analyzed 255 uh samples. So we had the breast milk
00:14:27.920 samples and the breastfed infant follow up to the age of five. So we analyzed
00:14:35.920 we quantified der in this breast milk and then we we compared the babies that
00:14:42.000 received houses might breast milk with the babies that receive
00:14:47.120 with no houses might smite in breast milk. And what we saw is that
00:14:52.959 having that house smite in breast milk were related uh to a high risk for uh IG in the
00:15:00.880 infant here in the total population a borderline to specific IG and higher
00:15:07.519 risk for asthma or allergic rhinitis here in the group of allergic mods.
00:15:15.839 So opposite for over we see that if we have we can find houses might breast milk in
00:15:23.120 half of the population and the presence of uh dwan that’s the allergen in breast
00:15:29.360 milk actually increase the risk for sensitization and historical allergy.
00:15:36.639 Uh so the question now what is responsible for this prologenic effect of houses might if we compare to aa that
00:15:44.160 was inducing oralness. So most of houses might allergens has
00:15:52.399 some enzyatic activity. So for example one is a cyain protease and we have also
00:15:59.839 tine three is a protease and it has been demonstrated that those
00:16:07.519 uh protease in the protoepithelial cells. It can directly digest the the
00:16:15.120 digestions between the cells and as a consequence you have a leech barrier or
00:16:21.360 it can bind directly to power receptors and then you have reduced allergies like
00:16:28.240 IL35 33 and TSOP and these will activate ILC2 cells and induce the proliferation
00:16:35.600 of TH2 cells. So it will induce a type two immune response that is related to
00:16:40.720 to allergy and this is well described to the lung and also in the skin.
00:16:49.680 So knowing that we have houses in breast we wanted to to know what’s happening
00:16:56.160 the gut of the baby. So we use the same uh animal model where
00:17:02.880 exposure the lactate mother to house spites but now it does two different houses might we give the houses might
00:17:10.160 with the protease activity in a house might where we inactivated the protease
00:17:15.599 with inhibitors and then we looked to the the milk to see if we could find the
00:17:20.880 allergen and protease activity and also what was happening
00:17:27.599 in the gut of is breastfed meates uh to the cateier and also immune cells.
00:17:38.000 Uh so in the milk uh we could find the presence of the
00:17:43.200 allergen both receive houses might with protease or no protease both had the
00:17:50.160 protein there the allergen but the protease activity was much higher uh in
00:17:56.880 the milk lactating mothers that received house the smite compared to control.
00:18:05.120 So indeed hoses smite is transferred to breast milk and it still has the the
00:18:10.480 protease activity there. So then we look to the gut of this um
00:18:18.160 neonate that receive houses breast milk and what we see that exactly as was
00:18:24.240 demonstrated in the lung and in skin uh if you have that house smite in breast
00:18:29.840 milk increase the gut barrier. So we saw a leak bar here increase the release of
00:18:36.960 alerine so 10 times more IL33. Uh we have an activation of ILC2 so they
00:18:43.919 secrete more IL5 and IL13 and it was
00:18:49.440 uh also related to uh expansion of TH2 cells in the luminopia.
00:18:56.320 So this demonstrated that even that really tiny amount of houses might
00:19:02.160 ingress milk, it can damage and induce a type to inflammation in the gut of uh
00:19:08.240 the unit. Okay. So uh I show you that we have a
00:19:15.440 smite in breast milk and due to this protease activity it will act as an
00:19:21.600 adjuant and induce this immune through the gut.
00:19:27.360 uh in the other hand we know that uh now that you have breast milk you can induce
00:19:34.720 uh heulatory cells and then induce oral tolerance and protect from allergy.
00:19:41.360 So the question now is is this um aduant property of houses might
00:19:49.440 impacting the oral tolerance to an unrelated allergen if it’s there in the
00:19:54.880 gut at the same time. So h can we still protect from food allergy and induce
00:20:01.360 oral colorance in the presence of dirt. So to answer this question now I will
00:20:07.679 give both allergens the same time to the mother in the animal model
00:20:16.160 and then we look in the gut to see what was happening. So first we confirm that
00:20:22.000 yes if we give egg to the lactate mother uh in the breastfed b we can induce
00:20:31.120 cell. So here here’s the control. So we increase the number of over specific tur
00:20:37.520 cells and we also protect against food allergies. So here is diarrhea score and
00:20:43.760 over specific HA. However when we give both allergens the
00:20:51.520 same time houses might over then we abolish the capacity to over to induce.
00:20:59.280 We don’t have this anymore. Then also we abolish the protection against futility.
00:21:07.840 And if we give the houses light
00:21:12.880 store then the ability uh for tre and production.
00:21:21.600 Um so yeah so just to conclude here so yeah
00:21:27.600 having house test might impress milk it’s a risk factor also for food allergy
00:21:33.840 here in our animal model. So as always we wanted to translate this to
00:21:41.280 uh the human scenario. So we looked in a human cohort now human cohort to see if
00:21:48.480 the presence of houses might in breast milk was now related to food allergy.
00:21:55.200 So first we analyze uh the milk samples from this cohort for the presence of the
00:22:01.280 one and over. And as we can see here is quite aogenous. So some moms will have
00:22:09.039 like no allergen in breast milk. Some moms were positive. So this is this
00:22:14.480 group. Some were like positive for that but negative for here. Some positive for
00:22:22.640 and negative for that but some have both allergens. So we split
00:22:29.200 uh the amounts on these groups the the infants actually that we see breast milk
00:22:34.880 look without the allergens and then we look the prevalence of IG mutilated egg
00:22:42.000 allergy and exactly as our last model we saw
00:22:47.919 that the higher prevalence of IG mediated egg allergy was in the group of
00:22:54.480 babies that received in breast milk but no ova and the lowest
00:23:00.080 prevalence was in the group that babies that receive nerve sorry that this is
00:23:05.600 over but no dirt. So showing again that there may be a
00:23:11.280 risk factor for food allergy and over a protective factor for food.
00:23:20.799 Okay. So um in conclusion we know that how now that houses might in breast milk
00:23:27.360 is not good. It can increase the risk for allerg sensation and respiratory
00:23:32.480 food allergy. So it looks like if we want to improve allergy prevention through breast through breast milk we
00:23:38.880 need to find a way to uh avoid the presence of houses might in the milk.
00:23:45.200 So the question is can we prevent houses might shed in human milk uh by
00:23:50.320 environmental control. So we look to that. So we just published
00:23:57.360 last year this last year in 2020 this paper uh and we look at in Pama cohort 2
00:24:09.840 54 samples sorry and we look the presence of Dwan in breast milk and in
00:24:17.279 the test and then we choose maternal mattress to look to that. So here we have uh 36%
00:24:25.600 of the samples in breast milk were positive to their one and 64 the samples
00:24:31.600 of maternal matrix was positive to to the one and the question was is this
00:24:37.840 related to the presence in breast milk. So we found absolutely no correlation
00:24:45.360 between house to smite in the dust and the levels or the presence of house and
00:24:51.279 smite in breast milk. So here in this first graph you can see the
00:24:57.120 concentration of D one breast milk and we split the MS that were negative to D
00:25:04.159 in the the dust and the moms that were positive uh in the dust and you see that
00:25:10.320 the concentration it’s really similar uh between both groups and here we have the
00:25:16.320 just the percentage of positive samples in breastfeed if the moms were negative or positive to
00:25:23.120 the dirt in the dust in the mattress and the percentage of positive samples are
00:25:28.480 the same and here is the correlation between that one in breast milk and that one in maternal mat and there is no
00:25:36.640 correlation so uh actually we weren’t like surprised
00:25:42.640 with this data because in our previous uh work we analyzed some proxy of
00:25:49.520 allergen exposure we didn’t have the measurement of their one in the dust. But we knew some like if the moms have
00:25:57.679 carpet at home or the habit of cleaning or the number of habitants in home, some
00:26:03.760 proxy of allergen exposure and we also didn’t find any correlation with the
00:26:09.360 levels of their one in breast milk. We also had some um data from the Brazilian
00:26:16.240 cohort on the levels in breast milk and and death. that’s not published and there is no uh correlation and uh we
00:26:26.000 know that there is also a poor correlation between the presence of food allergens in breast milk and the
00:26:33.679 maternal food allergen consumption even in the clinical trials where we know
00:26:39.600 that the amount of food allergen it’s really well controlled. So here in the
00:26:46.559 table uh you see some examples of like egg allergen in breast milk. So for
00:26:54.000 example uh in this randomized clinical trial where the mom receive for example
00:26:59.600 one cooked egg only 68% with secret in breast milk or
00:27:06.720 here high egg diet 68% only the secret
00:27:11.760 egg in the milk. So half of the lactating mothers do not secrete allergen in breast milk even after
00:27:20.400 control amount inest. And what is more surprising is
00:27:25.520 that the moms that were under this strict diet with no egg consumption
00:27:33.360 always also secret some allergen breast milk. For example, uh this is a low egg
00:27:40.159 30% had allergen in breast milk. Eggfree diet 37% had allergen in breast milk.
00:27:47.600 And this can be explain it by some exposure to egg in the environment.
00:27:53.840 For example, exactly like house the smart might.
00:27:59.039 And so finally uh we use again the PMA
00:28:04.240 birth cohort. Uh what we wanted to know is u if houses might really independent
00:28:12.000 source of of allergen exposure. houses matching breast milk was an source of
00:28:18.080 exposure. So in the same cohort we had access to
00:28:23.440 breast milk and and the dust and then we measure that
00:28:28.960 one in the breast milk and the dust and we did the clinical um
00:28:34.799 followup until the age of 16. So then we compare the levels of total
00:28:42.960 HA and the prevalence of asthma in the infants that were exposure to their one
00:28:49.679 through breast milk or to dust. And what we see is that exposure to breast milk
00:28:55.840 uh was related to increased risk for high levels of total IG
00:29:02.559 and a trend for um higher um prevalence
00:29:09.120 to asthma that wasn’t observed here when it was uh exposure through the dust. So
00:29:16.159 there is what does this associate with uh this increased level total IGA
00:29:23.520 and this is in accordance with our previous data again French cohort and
00:29:30.159 also previous data in the PMA birth cohort showing that exposure through the
00:29:37.120 dust doesn’t increase the risk for asthma or sense disease.
00:29:45.520 So in conclusion uh now we know that early life breast
00:29:51.360 milk is also to be considered a source of infant exposure through house night
00:30:00.240 in breast milk can act as an advent and increase the risk for allergy
00:30:05.760 sensitization respiratory instant allergy and the levels of their one in
00:30:11.520 breast in the dust is not correlated to the levels in human milk. So we can
00:30:17.200 consider breast milk as an independent source of causes might exposure early in
00:30:23.200 life. And I think the key message actually is
00:30:29.360 uh that now in in this area that we
00:30:34.640 exposure the kids very early in life to induce oral tolerance not to allergens.
00:30:39.840 We need to know that over can also be a root for allergic sensitization even in
00:30:45.919 the presence of all this breast milk and depend on the the allergens that you
00:30:54.000 are exposing.
00:31:00.480 So knowing now that houses might smite in breast milk is not good to to prevent
00:31:06.159 allergy and we can’t really control the presence of houses might in breast milk.
00:31:12.080 How we can promote allergy prevention through breastfeeding. What’s next? So we really think the good strategy is
00:31:18.960 doing some maternal intervention to modify the breast milk uh composition
00:31:24.960 and try to promote a more breast milk. So doing that we believe
00:31:31.120 that then we can create in the gut of the baby a moreergenic condition. So
00:31:36.799 when the infant will be in contact with the food allergen we can use or
00:31:44.159 another way to start to modulate the allergen checking in normal milk
00:31:49.519 increasing or decreasing depending the other means then controlling exposure
00:31:57.120 and for that we think that the diet and maternal microbiot is really
00:32:04.480 uh important and good targets because we can modify and we believe that by
00:32:10.000 changing the the diet and microbial the way that the mom will digest the antigen
00:32:15.600 will be different and this will impact uh how this allergen will be shedding in
00:32:21.600 the milk. So we started to to investigate that. So
00:32:28.320 we have a project on that it’s the gateway forage prevention. So it’s a
00:32:33.519 project that we use samples from the Simba randomized clinical trial that’s
00:32:39.519 from origin cohort and in this in this trial the moms will receive
00:32:47.039 prebiotic supplementation during pregnancy and breastfeeding and then we will analyze the breast milk
00:32:53.919 samples at two, four and six months uh for the presence of many bioactive
00:32:59.679 molecules the microbiota for But we also uh wanted to see uh the
00:33:06.000 allergens food and houses might allergens breast milk and the protease
00:33:11.360 activity in breast milk. So to see if this prebiotic supplementation can shape
00:33:17.679 this breast milk composition for more tolerogenic composition and then of
00:33:24.480 course we’ll see if this can then decrease allergic risk in the infant. So
00:33:29.760 I don’t have data on that uh now. So state I hope uh soon we’ll have some
00:33:35.760 very nice data to show you about this project.
00:33:41.039 So that’s all for today. I would like uh to thank you first my team. This is the
00:33:47.919 team of Hasset head of the center of breastfeeding and immunology.
00:33:54.080 Uh this is myself. This is Akila, a postto that she’s responsible for most
00:34:00.240 of the mouse models that I I show you. Uh this is Lick that she’s going to to
00:34:06.880 give a talk about the uh breast milk microbiota. This is Ni.
00:34:12.800 She’s working that uh work that I told you was in our cohort. And this is Sabana
00:34:19.440 student in our team as well. So I would like to thank also all our collaborators
00:34:25.679 especially the ones involved in all those birth cohort and our sponsors
00:34:32.800 and you for the audience. So I hope you have learned something new today. Thank
00:34:38.480 you.