Mastering Rh Blood Group System

right today we are going to talk about Rh blood group system but while discussing Rh blood group system I would love to compare and contrast the Rh blood group system with blood group system right as we know that these blood group systems consist of antigens and antibodies right now first of all we'll come to that rh blood group system how it was discovered Rh blood group system how it was discovered and why it is named as Rh you must be knowing rh basically stands for rhesus monkey rhesus monkey what really happened at around 1940 right during some experiments red blood cells from the rhesus monkey there's a happy monkey red blood cells from the rhesus monkey were injected in some small animals like rabid RBC's from the rhesus monkey they were transfused these red blood cells into the circulation of rabbit or guinea pig right and then they form that the small animal was making antibodies right and those antibodies were able to cross react or gluten ate 100% of the red blood cells from all rhesus monkeys again listen we took red blood cell from the smokey rejected into rabbit right of course this red blood cell which is brought from monkey to the rabbit this red blood cell has many antigens right and many of these antigens are foreign to the rabbit system right now rabbit will make antisera right and these antisera what were tested on RBC is derived from rhesus monkeys and all rhesus monkeys for example to 200 monkeys and in all those monkeys their red blood cells were able to react with this antisera this is a right so it was speculated that red blood cells of the monkey contained antigen and that antigen was named as resident agent that was named as racist antigen later on the same antibodies were tested on human RBC's they were tested on human RBC's and it was found that the same antisera was able to yes able to gluten ate or react with red blood cells from almost 85% of white population right again I will repeat what was happening yeah whatever antisera was produced by the rabbit against the RBC's antigens of rhesus monkey same antisera was able to react with the red blood cells or of gluten ate the red blood cells from almost 85% of white population occasions right European population white European population so and but in about 15 percent and 15 percent of the population red blood cell did not react with this antisera is that right now what does it mean it means simply that when races RBC's were rhesus monkey the RBC's were entered into rabbit or guinea pig the antisera which was derived of course it was able to gluten eight red blood cells 100% derived from the all the rhesus monkeys but surprisingly it was also able to be lutein ate the red blood cells derived from white population of about 85 percent right but it was not able to antisera was not able to be innate or react with 15 percent of the white population then it was speculated that this 85% population right this 85 percent of white Americans or Westerners population right there they are having something common in their red blood cells and monkey red blood cell right that this antigen which is present on this rhesus monkey it must be present over here too and this antigen should not be present over here am i clear to everyone it's so simple now all those people whose red blood cells were agglutinated or reacting to this antisera they used to say they are having antigen yes antigen similar to rhesus monkey RBC or the simply call it these people are having RH antigen what they were calling Rh erases antigen or they simply said these are Rh positive people these people are Rh positive and here those people who are not reacting to that antisera right they said that these are Rh negative before I really go ahead I should be thankful to the doctors of other people who discovered all this thing they just call it Rh positive thanks God they didn't call it a monkey positive otherwise many of us will be monkey positive and some of us will be monkey negative right so thanks God when we are talking as doctors we will say I'm Rh positive and we don't say we are RH monkey positive right so let's go back so this is initially how this RH system was discovered right now I will go into detail up to now we have just seen that basically those people who have RH antigens on their red blood cells they are considered Rh positive and those people who do not have RH antigen in their on their blood they are considered Rh negative but things are not so simple let's go into detail because this story was in 1940 but now so many years have passed decades decades have passed and we have learned so much about RH system so now we remember that now our each system consists of not one antigen it consists of a whole system of antigens up to now they're more than 50 RH antigens they're more than 50 RH antigens but some of them are more important and others are less important clinically right so let's pause here is an RBC right now this is red blood cell from an Rh positive person from an Rh positive person it means this red blood cell has RH antigen actually what is what is exactly the nature of RH antigen what it is what is its structure because it's important to know because if we know the nature of the RH antigen we can speculate what kind of antibodies will be found against those antigens basically RH antigens are proteins RH antigens are proteins and these are the protein peptide chain which passes through yes this is a peptide chain and this peptide chain passes through the red blood cell membrane 12 times how many times 12 times that is why we call it 12 pass membrane proteins membrane proteins and these proteins are the integral part of red blood cell membranes they are the integral part of red blood cell membrane that is why we also call them membrane proteins so RH antigens are fundamentally proteins which are embedded within the membranes of red blood cells and they are 12 pass 12 times the passes to the membrane so they have 1 2 3 4 5 6 6 extracellular loops and 6 and draw cellular loops and these are of course if this is protein a peptide chain one and should be a minor and then there should be carboxyl and and both of minor and carboxyl and intracellular right antigenic determinants are over these loops antigenic determinants or epitopes are on the extracellular lue is that right now later on it was discovered that RH antigens are of different types right most common and very strongly immuno genic is D antigen let me put it over here this is the D antigen right now what are the cletus the antigen this is one epitope of the D antigen I'm showing this D antigen is part of this peptide chain so it means it is the special sequence of amino acids right so we can say the antigen is basically one of the yes component of or minor acid sequence of this 12 pass membrane protein now as I told you that RH antigens there are more than 50 discovered out of them the five are very important 5 5 antigens are very important one is D other is capital C or at its place small C or capital or small e so how many are there capital D antigen capital C antigen of small C antigen capital e antigen or small e antigen remember there is no small D antigen when we say that is small D actually means there is no D right so these RH antigens are also called Rh factors these RH antigens RH antigens are also called Rh factors so out of this more than 50 antigens or more than 50 RH factors the most important are b c and c e and Smalley all of them are slightly different from each other now here I want to highlight one more thing now this is a peptide chain which is having D antigen actually D antigen has many around 4 antigenic determinants but I'm just showing one right then what about C and E there is another this is another molecule and on extracellular loop number two there can be either capital e or C or small C right remember D have shown with these things why I am showing like this because it is very strongly immuno genic once D antigen enter in the body of a person who is not having D antigen as self addition this guy this can or this may induce a strong immune immunological reaction then this is C and on forth extracellular loop there is another here and this is e so what I have shown okay let me make the color different this is D right here it is C and here it is E right now basically these proteins are quoted by the genes they are quoted by the genes blood but RBC's do not have genes the addresses of genes their genetic material nucleus so from where the the genes are how these membranes can make such proteins yes the throw blast yes retro blast and precursors health precursor cells of the red blood cells they do have genes and there are two genes which are responsible to make these antigens one gene is of course they are not in RBC's they are in precursor cells those are this is like prod throw blast one gene is I can say are H D gene which is making this molecule and other is our H C E which is making this molecule later on we'll discuss about these two genes right for a while you just trust me then there are as long as far as these important variants of RH factors or antigens are concerned our HDR by the RH D gene RH defector and Rh C and E they are determined by presence and function of the rhce genes is that clear now these are RH antigens let's compare them with system antigens let's compare them with system antigens system antigens are not proteins system antigens are not proteins they are basically carbohydrates there are small chains of monosaccharides those small chains of monosaccharides are called oligo saccharides so basically blood group a it has one type of chain and blood group B has different type of chain now people who have blood group a they are having a antigens on their red blood cells a antigens are basically oligosaccharides people who are blood group B they are having B antigens and B antigens are also oligosaccharides and people who have blood group O they do not have a and they do not have B antigens am i clear now if someone asked what is the major difference as far as what is the major difference in the antigens of RH system and system the first answer should be RH system antigens are proteins RH system antigens are proteins and system antigens are oligosaccharides carbohydrates and easy and funny way to remember that we can say RH antigens are like chicken pieces chicken pieces and these are the sugar candies these are the sugar candies so if your RBC's again next time if you are confused just remember people who are Rh positive they are having protein issue proteins antigens or chicken pieces and people who are right group they are basically ki having sugar candies carbohydrates oligosaccharides am i clear any question up to this right now we move forward out of these I told you they're more than 50 out of those 55 are the most important either Big D antigen is important Big C or small C big or small E but among all of them among all of them the most important is D antigen most important is D antigen or Rh defector we call it RH D antigen or factor now this rh d how many types are h d rh yes see and then Rh small c right then Rh Big E and then Rh small e right so these are five most important RH antigens but among them which one is the most important clinically most important is rh d why it is so important because number one which is most prevalent it is most prevalent most commonly found and number two it is most immunogenic most immuno genic most immunogenic mean for person who does not have D antigen a person who only the RBC's person does not have D antigen it means that person is Rh negative if you inject him D antigen or D positive RBC's person might produce a strong reaction against the antigen person may produce an TD antibodies person may produce NTD antibodies but other antigens are not so strongly immuno genic they are immuno genic but they are not so strongly as D antigen right in the hand if D antigen is the most important and most strong antigen and most immuno genic so in common medical practice when we talk about that person is Rh positive actually we are talking about that person is Rh positive person is equal to D positive in common and general medical practice when we say that my patient is Rh positive actually I mean person is D positive and if I say the person is Rh negative it means person is D negative so now onward in our discussion during the lecture we will follow this simple rule that when I say someone is Rh positive if I don't mention specifically about C and E it is understood I am talking about D so D positive people are Rh positive and D negative people are Rh negative is that clear any question up to this now few more words about D antigen okay let me make red blood cells and these are three red blood cells okay four red blood cells a very important terminology let's suppose and this is the D antigen okay I will make it more simple this D antigen I'm just showing by D now these are D antigens present on this red blood cells so of course this will be D positive it will be D positive red blood cell there are no D antigen if there are no D antigens what is this D negative is that clear so this is what an average doctor should know very well if we every doctor does not know this it's very sad situation the minimum a doctor should know about RH system is if person is having D antigen person is Rh positive say loudly and if person does not have D antigen person is Rh negative right but now move on some people have the antigen but very few molecules very few molecules the density of the antigen is very less on red blood cell if density of D molecule is very very less we call it weak D what we call it weak D so we have Rh positive patients or people we have Rh negative or D positive and D negative and sometimes we come across people who are weak D why we are talking about weak D because sometimes we do people have very less D molecules right and they may not be sometimes detected by the some of the available antisera so VD means that okay let's suppose we just call it D antigen is mean dog we're just talking about it so so many dogs there are so many dogs and d+ d- no dogs and veal the few dogs few dogs now every dog has how many egg for D antigen alphas for antigenic determinants D antigen as for antigenic determinants or for epitopes right now here are four okay let let me put it they are having four upside-down dogs not five okay let me make there more artistically let me try my art these are the dogs these are D antigens right one two three four one two three four so they are having four legs these are normal D antigen with the high density and these people are called D positive or Rh positive these people don't have these dogs if they don't have these dogs these are D negative or Rh negative very good now here there are very few dogs very few dogs but dogs are normal but very few right so this is called weak dog then another category is partial D partial D now what is partial D the difference between partial D and weekdays that some of the legs are broken one or two legs are missing D molecules are there but maybe only two legs or only one leg or only three legs so it means as compared to D positive we D has quantitative difference quantitative difference and as compared to the D partial D as qualitative difference quality of the D antigen is not right right so I'm just introducing the few terms first of all D positive people where D antigen the negative people who do not have D antigen clear this is for a good doctor a very good doctor sometimes we come across weak D where D antigens are normal but lesson number or sometimes we come across patients who are partial D partial D are those people who are having slightly abnormal qualitatively abnormal D antigens or missing some of the epitopes is that clear okay then another term is we will talk about d+ d- VD partial d another is RH null another term is RH null it's rare but what is it yes yes RH null mean there is no dog no dog but the negative is also having no dogs no no listen my friend here the antigen is present here the indigenous not present here D and digit concentration is very low here D antigen whatever concentration is abnormal structure then another term sometimes we come across in the literature RH null what does it mean if we say there is no D then it should be called simply the negative so there's something more excellent very good actually RH null is the person who is considered no D no II know C none of the RH antigen is there out of important because come here when we say D positive we are talking about D but we are not talking about C and E which may be present here in the same way when we say D negative right it means even though we said generally speaking Rh negative but there may be C or E or may not be you are understanding but when we say RH null it means there is no D there is no C there is no e listen carefully come back I said there are two genes I said there are two genes now in this person RH D gene is expressing very well here RH Dean is our a gene is our HD gene is absent or totally non-functional is the right in this case our HD genus either under expressing or molecules which are produced cannot be expressed from the membrane or their gene is mutant in such a way that some of the products are abnormal right but in all these stories we didn't talk about rh c right when actually there are no products from here as well as no antigenic product from here then we say this is our H null these four terms are clear any question up to this okay now let's move forward now we know if a person is having D antigen we call him Rh positive or we simply call it or we simply call that positive blood group or we simply call it positive blood group and a person who does not have D antigen we call him negative blood group we call him negative blood group now we come to the how many blood groups we can have as we know that let me draw red blood cells here and draw the Orbeez okay these are the red blood cells now let's start with simple thing first of all we classify these red blood cells according to group let's suppose it has sugar ring a saccharide a what is this blood group a right this has only B antigen so what is this blood group B if it has a and B both what is blood group yes a be very good it doesn't have a or B it has only actually a chant agent no a no B because remember a and B and teach-ins are basically modified H antigen so when H antigens are there on red blood cells but they are not modified by addition of terminal monosaccharide they are not modified into a or b we simply call them they don't have eight they don't have B but it doesn't mean that don't have any antigen they have a chant agent is there right so but those people's red blood cells which do not have a and they do not have B we call them traditionally which blood group O is the right am i clear and so these are about the candies if you have candy a blood group a but with the candy if you have candy B blood group B if you are two types of candies so sweet like me blood group a and B and no kind is this is o is it clear now you imagine with the candy you put the chicken piece D antigen this is D antigen so what will say this according to system it is blood group a according to the arch system it is positive so it will become a positive blood group if you put a chicken piece here also this will become the positive red blood cell right if we put a chicken piece here I mean D antigen then what we say person will be a vn+ blood group a B+ and if a person has D over here chicken pieces there but no candy but there is no candy only wrappers of the candies are there there's no candy then what we call it o+ it means that someone has red red not self with only a antigen it is a and no chicken piece it is a negative someone has be sorry someone has B antigen but no chicken piece so what we call it B negative if someone has a and B candies yes oligosaccharides right then we'll say blood group a a and B but no D so we'll call it a B negative and someone who has only H antigens no a no B and no D we'll call it o-negative so this is how we can classify red blood cells by two systems system and Rh system is it clear actually there are so many blood groups more than 35 systems of blood groups but two are most important system and Rh system right so here I have shown system and correct system one more thing which I want to make it clear is that in the beginning I said that people who are d+ people who are d+ they are also considered Rh positive what is the distribution of Rh positive and negative in the population actually in American whites in American why it's about 85 percent people are Rh positive they are Rh positive but in you go for American blacks blacks then it is about 95 American blacks are Rh positive but if you go for African blacks African blacks 100% of the African blacks are Rh positive and if you come to Asians Asians almost 99% are Rh positive so we can say when we say Rh positive it means D positive you can see that D antigen is very very common in eighty five percent of white Americans and ninety five percent of black Americans 100% of African blacks and Asians ninety-nine percent population as de antigens it means in the world population most of majority is D positive or Rh positive right now after this we'll discuss other aspects about these antigens right first we'll have a break and then after that I will continue with some important clinical differences between the RH antigens and a Burin taejun's

Channel: Dr. Najeeb Lectures

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Keywords: rh, blood, group, rh negative, blood type, blood transfusion, transfusion, rh-, dna, rh+, abo, abo blood group, dr najeeb, dr najeeb lectures, medical videos, medical lectures, usmle step 1, usmle, medicine, medical school, medical education, blood types, abo blood group system, blood groups, blood physiology, physiology, histology, blood tansfusion, blood typing, lecturio, what is blood type, usmle step 1 videos, blood group, blood group o, blood group a, blood group ab, ablo blood

Id: fwO-k8P67ac

Length: 36min 38sec (2198 seconds)

Published: Fri Oct 27 2017