RHESUS FACTOR

From Big Medical Encyclopedia

RHESUS FACTOR (rhesus — according to the name of a species of monkeys of Macacus rhesus) — the system of allogenic antigens of blood of the person independent of the factors causing blood groups (AB0 system) and other genetic markers.

River - f. the person it was opened in 1940 by K. Landshteyner and A. Winer. The system of antigens received the name «Rhesus factor» because its antigen was found in the person by means of serum of a rabbit, immunizirovanny by erythrocytes of a monkey of a type of Macacus rhesus. River - f. it is most expressed in erythrocytes. Less accurately it is presented in leukocytes and thrombocytes. In a blood plasma of R. - f. it is not found.

There are six main antigens P. - f. Dly designations of this system of antigens equally use two nomenclatures: Winer's nomenclature and Fischer's nomenclature — Flight. It agrees the first — antigens P. - f. designate Rh symbols 0 , rh', rh", Hr 0 , hr', hr"; it agrees the second — use alphabetic references: D, With, E, d, with, e. Quite often use two nomenclatures at the same time. In this case symbols of one of designations place in brackets. A large number of options of antigens in R. - f. allowed Rouzenfildu (R. E. Rosenfield) et al. in 1962 to offer the new digital nomenclature of designation P. - f. It included Rh-Hr antigens from Rh 1 to Rh 35.

Synthesis of antigens P. - f. it is controlled by genes of the first couple of chromosomes. Existence in R.'s erythrocytes - f. it is coded by six genes linked on three on one chromosome. Couples of genes controlling antigens D — d, With — C and E — e since each individual contains six genes controlling R.'s synthesis - f are allelic. However the smaller number of antigens phenotypical can be found (five, four, three) that depends on number of tomozigotny loci at an individual.

Antigen (factor) Rh 0 (D) — the main antigen in R. - f., imyoyugtion the greatest practical value. It contains in erythrocytes of 85% of the people living in Europe. Rh antigen 0 (D) is not homogeneous, it includes a number of smaller subunits — Rh A , Rh B , Rh With , Rh D , owing to distinction to-rykh sometimes develops hemolitic disease of newborns (see) at Rh-positive mothers.

On the basis of existence in erythrocytes of Rh antigen 0 (D) allocate a Rh-positive blood. Blood of people, erythrocytes to-rykh are deprived of this antigen, carry to Rh-negative type. Otherwise approach donors with blood of Rh-negative type. Their erythrocytes shall not contain any of three antigens — Rh 0 (D), rh' (C), rh" (E). Such approach to assessment a Rhesus factor accessory of donors allows to exclude a possibility of a sensitization of the recipient to these antigens and to substantially reduce danger of posttransfusion complications. Rh antigen 0 (D) in 1,5% of cases meets in poorly expressed genetically caused option — a kind of D u . Rh antigen 0 (D) it is unevenly widespread among representatives of separate races. In process of advance from the West to the East the frequency of its existence significantly changes. At the European population the frequency of occurrence of persons with Rh-negative type of blood makes 15%, and at Mongoloid races — apprx. 0,5%. Overwhelming number of inhabitants of Asia are carriers of Rh antigen 0 (D) therefore among pregnant women there are immunological havocs according to R. - f., meet less than among pregnant women of the European population.

Allelic to a gene of Rh antigen 0 (D) the gene of Hr antigen is 0 (d). Existence of Hr antigen 0 (d) it is not proved as to it the corresponding antiserum is not received. The expected frequency of occurrence of this antigen among the European population makes apprx. 63%.

Rh antigens' (C) and hr' belong to the second couple of antigens controlled by allelic genes (c). Rh antigen' (C) it was opened by A. Winer in 1941 by means of the blood serum received from the patient with the hemolitic reaction which arose after hemotransfusion. Frequency of occurrence makes it about 70%. There are several options of this antigen (C w , With x ), differing on degree of manifestation. Rare occurrence of these options (C w — 2,5, S x — 0,001%) define their small importance. Hr antigen' (c) it was open two years' later by means of blood serum of the Rh-positive woman, edges gave birth to the child with hemolitic jaundice. Frequency of occurrence of hr' makes (c) apprx. 80%.

The third couple of antigens, synthesis to-rykh it is controlled by allelic genes, make rh antigens" (E) and hr" (e). Rh antigen" (E) was discovered by A. Winer in 1943. Frequency of occurrence of antigen makes apprx. 30% among the European population. Hr antigen" A. E. Mourant in 1945 was open (e). Frequency of occurrence - this antigen apprx. 97%. M. A. Umnova (1976) notes the following frequency of occurrence of antigens P. - f. among Russians: Rh0(D) — 85,03%, rh' (C) — 70,75% of „rh" (E) — 31,03%, hr' (c) of-84,04%, hr" (e) — 96,76%.

Very seldom blood of the person does not yield positive takes with one blood serum against antigens P».-f. Erythrocytes of such blood designate Rh null. Erythrocytes of Rh null remind type of blood Bombay deprived of all antigens of the AB0 system (see. Blood groups ). It is considered to be that persons with erythrocytes of Rh null have a gene of Xr 0 in a homozygous form, to-ry represses production of antigens P. - f. Such persons can transfer to children antigens P. - f., phenotypical without showing these signs. Existence of a gene of Hg0ukazyvayet on pathology As at persons with erythrocytes of Rh null the disturbances of a membrane of erythrocytes causing their bystry destruction are often observed.

One of kinds of R. - f. the LW antigen designated so by last name researchers K. Landgyteyner and A. Winer who opened it is. LW antigen comes to light generally heteroimmune blood sera received from Guinea pigs against erythrocytes of monkeys of Macacus rhesus. Antigen contains at 99% of people is independent from their Rhesus factor accessory. LW antigen includes Rh antigen 0 (D). Therefore serums of anti-LW after adsorption by Rh-negative erythrocytes gain specificity of anti-Rh 0 (D).

Antibodies against R. - f. (see. Antibodies ), as a rule, immune. Definition of antibodies an anti-Rhesus factor is made by method hemagglutinations (see). In reaction use erythrocytes of the person of the known accessory according to R. - f. It gives the chance to define also specificity of antibodies. Besides, the quantitative characteristic of antibodies is established on a caption of the studied blood serum. For this purpose define the last cultivation of the studied blood serum, a cut shows still a positive take. The anti-Rhesus factor is the main reason for antibody formation hallo - more rare an autoserotherapy (see. Autoallergy ). Antibodies of anti-D, anti-With, Anti-E are most often formed.

Distinguish two types of Rh antibodies: full and incomplete. Vhole antibodies an anti-Rhesus factor have ability to stick together Rh-positive erythrocytes. They do not pass through the unimpaired placenta, treat preferential IgM, meet less often incomplete and owing to this fact have smaller value in medicine. Monovalent antibodies an anti-Rhesus factor have ability to agglutinate Rh-positive erythrocytes only in the presence of colloid solutions (substances with big molecular weight), after processing by proteolytic enzymes or at addition of specially prepared antiglobulinovy serum (see. Koombs reaction ). They meet more often than vhole antibodies. Their molecular weight is much less thanks to what they get through a placental barrier easier and therefore are more aggressive. Monovalent antibodies an anti-Rhesus factor belong generally to IgG. Autoimmune antibodies are, as a rule, monovalent antibodies against Rh 0 , hr" and other antigens P. - f.; treat generally IgG.

Methods of definition

R. - f. determine by method of hemagglutination by means of the test serums an anti-Rhesus factor prepared from blood of Rh-negative persons sensibilized to R. - f. repeated hemotransfusion or at pregnancy, and also from blood of the persons subjected to artificial immunization. Distinguish two basic groups of methods. Carry a method of agglutination in the salt environment to the first group, at Krom use the serums containing full Rh antibodies. At R.'s definition - f. by this method erythrocytes in the form of 2% of a suspension in isotonic solution of sodium chloride connect in small test tubes (height of 2 — 2,5 cm with internal to dia. 0,5 — 0,6 cm) with the serum divorced in half an anti-Rhesus factor. Test tubes place for 1 hour in the thermostat at t ° 37 ° then consider in a transmitted light by means of a magnifying glass and in a form of a deposit of erythrocytes (agglutination of erythrocytes) at the bottom of a test tube consider result. At a positive take — a deckle-edged deposit, in the form of separate threads or granularity. At a negative take — the deposit is located with a uniform layer and has an appearance of correctly outlined circle. The specified method has limited use as serums an anti-Rhesus factor meet vhole antibodies seldom.

Carry the methods based on use of serums an anti-Rhesus factor with monovalent antibodies to the second group to-rye in test tubes or on the plane agglutinate erythrocytes after processing by their proteolytic enzymes (trypsin, papain, proteliny, ficin, bromeline) or after addition of the substances promoting agglutination of erythrocytes (albumine, gelatin, Polyglucinum, polyvinyl pyrrolidol).

Among methods there are R.'s definitions - f. the method of the Fisc — Mac-Gui was widely adopted. It will be out in centrifugal test tubes, in to-rye gelatin places on 0,1 ml of a deposit of erythrocytes, serums an anti-Rhesus factor and 10%. Test tubes incubate on the water bath at t 46 — 48 ° then they add 8 —-10 ml of isotonic solution of sodium chloride. Test tubes 2 — 3 times overturn and consider result on availability of agglutinates, visible with the naked eye.

Apply also a method of definition of R. - f. on Petri dishes. At the same time use 5 — 10% a suspension of erythrocytes in autologous serum. Erythrocytes and serum an anti-Rhesus factor are applied on a Petri dish, to-ruyu placed for 10 min. on the water bath at t ° 46 — 48 ° then consider result of a research. Also express methods of definition of antigens P. - f gained distribution. These methods are based on use of serum an anti-Rhesus factor after addition to it of a certain number of 20 — 30% of solution of albumine of the person or 30 — 33% of solution of Polyglucinum. Researches are conducted on a white porcelain plate or in a test tube.

The main six antigens P. - f. can meet in a combination of CDE — 15,85%, CDe — 53,2%, cDE - 14,58%, ede — 12,36%. Among the listed antigens P. - f. not all have identical value. The most important of them are three antigens P. - f.: Rh0(D), rh' (C), rh" (E) having the greatest immunogene activity. Rh-negative persons as a result of hemotransfusion or repeated pregnancy can have alloimmune Rh antibodies. According to Daymond (L. To. Diamond, 1947), on one transfusion of 400 ml Rhesus factor-put-telnoy blood of 50% of recipients with a Rh-negative blood answer with antibody formation an anti-Rhesus factor. At transfusion of a Rh-positive blood to persons with antibodies an anti-Rhesus factor there are heavy complications caused by rough destruction of the poured erythrocytes and development of a hemotransfusionic complication. Rh0 (D) antigen has more expressed immunizatorny property, than two other its versions. The majority of the posttransfusion complications caused by Rh incompatibility is connected with it. In daily practice of hemotransfusion are limited to definition at the recipient only of Rh0 (D) antigen. It is connected with the fact that two other antigens — rh' (C) and rh" (E) are present at erythrocytes separately very seldom. Rh antigen' (C) meets in 1,36% of cases, rh" (E) — in 0,26%. When the Rhesus factor accessory of blood of the recipient does not manage to be established, transfuse it a Rh-negative blood. The immunogenicity of a Rh-positive blood was shown concerning persons, positive on a factor of D u , and also concerning the patient with a Rh-negative blood, transfused to Krom Nonpositive blood. Presence of D u - antigen allows to carry the recipient to Rh-negative type. Donor of the carrier D u consider Rh-positive.

Value

Distinctions of people according to R. - f. can lead to immunological conflict pregnancy (see. Pregnancy , Incompatibility immunological ). A sensitization hit in an organism of the Rh-negative woman of Rh-positive erythrocytes of a fruit is the cornerstone, of hl. obr. through vessels of a placenta.

The mechanism of development a Rhesus factor - conflict pregnancy is represented as follows. The immune antibodys which are formed in an organism of the Rh-negative woman pregnant with a Rh-positive fruit, being preferential incomplete IgG, get through a placenta into an organism of a fruit, causing hemolysis of erythrocytes of the newborn and injury of his vitals (the hemopoietic fabric, a liver, a brain). The symptomatology of immunological defeat of the child received the name of a hemolitic disease of newborns. Owing to extensive destruction of erythrocytes increase in amount of bilirubin, the expressed anemia with an exit in blood of a large number of erythroblasts, positive direct test of Koombs as a result of existence on erythrocytes of a fruit of alloimmune antibodies is observed. The main medical actions for fight against a hemolitic disease of newborns come down to bystreyshy removal from an organism of the child of products of destruction of erythrocytes. They include first of all exchange transfusions of a Rh-negative blood. Also other ways in fight against a hemolitic disease of newborns — prevention of a protivorezusny sensitization of Rh-negative women at the first pregnancy by administration of protivorezusny gamma-globulin develop.

Protivorezusny gamma-globulin is prepared from blood serum of the immune person, antibody-containing anti-D(DC) in a caption not lower than 1: 128 — 256. Administration of protivorezusny gamma-globulin in a dose about 300 mg in the first 48 — 72 hours from the moment of delivery prevents development of a sensitization at the following pregnancy to R. - f. in 90 — 100% of cases. The smaller dose of protivorezusny gamma-globulin (100 mg) is used at implementation of abortion at the Rh-negative woman. The mechanism of immunosuppressive effect of protivorezusny gamma-globulin is up to the end not found out. It is known that passive targeting at the Rh-negative woman of protivorezusny immunity reduces time of circulation in blood and destruction by macrophages and other cells a Rhesus factor-polozhptelnykh of erythrocytes of a fruit. Apparently, antigens P. - f. after connection with antibodies an anti-Rhesus factor lose the immunizing activity or there is an activation of T-suppressors (see. Immunocompetent cells ).

Antigens P. - f. are important in forensic medicine during the conducting examination on an exception of paternity (see. doubtful paternity ).



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E. A. Zotikov.

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