FIZIOPATOLOGIA SERIEI LEUCOCITARE

LEUCEMIA ACUTA

LEUCEMIA INTRODUCERE Leucemia este o afectiune maligna

characterizata prin proliferarea neregulata a unui tip celular. Poate interesa oricare dintre liniile celulare,

una sau mai multe linii celulare, sau celulele stem.

Leucemiile sunt clasificate in doua grupe majore:

Cronice, la care debutul, de regula, este insidios, boala este mai putin agresiva, iar celulele implicate sunt, de regula, mature

Acute, la care debutul, de regula, este rapid, boala este foarte agresiva iar celulele implicate sunt slab diferentiate cu multi blasti.

Modificari cantitative ale seriei leucocitare

Leucocitoza (cresterea numarului de leucocite peste 9.000/mmc) - poate apare in conditii fiziologice, prin modificari de distributie in arborele circulator sau prin solicitarea fiziologica a sistemului leucocitar (activitate fizica intensa, expunere la frig, digestie intestinala, graviditate, emotii, stres) sau patologice , prin intensificarea leucopoiezei medulare si prin mobilizarea leucocitelor aflate in circulatie sau in tesuturi ( infectii, hemoragii, inflamatii, afectiuni endocrine, neurologice, leucemii).

Leucopenia (scaderea numarului de leucocite sub 4000/mmc) - apare de obicei in conditii patologice: de distributie ( soc anafilactic, frisoane), prin inhibitie medulara ( infectii), de epuizare, prin inhibitia leucopoiezei ( dupa iradiere cu raze X, toxice chimice).

Neutrofilia ( cresterea numarului de granulocite neutrofile peste 7000/mmc)- apare prin mobilizarea rezervelor medulare sau prin cresterea productiei de granulocite ( infectii bacteriene, necroze inflamatorii, tulburari metabolice, administrarea de corticosteroizi, hemoragii acute si hemolize, afectiuni mieloproliferative).

Neutropenia ( scaderea numarului de neutrofile sub 2500/mmc) - apare ca urmare a productiei scazute de neutrofile ( prin proliferare medulara redusa, granulocitopoieza ineficienta) sau ca urmare a scaderii duratei de supravietuire in circulatie a neutrofilelor ( prin accelerarea trecerii in tesuturi a neutrofilelor in infectii, inflamatii, sau prin distrugerea neutrofilelor de catre anticorpi -hipersplenism, defecte de maturatie).

Eozinofilia ( cresterea numarului de granulocite eozinofile peste 400/mmc) -apare in afectiuni alergice, parazitare, dermatologice, hematologice, tumori, imunodeficiente, sau asociate altor afectiuni ( sindrom Loffler, aspergiloza bronhopulmonara, pleurezia cu eozinofile, poliartrita reumatoida, poliarterita nodoasa, dermatomiozita, fasciita eozinofilica, sindromul Churg-Strauss, sarcaidoza, boli renale cronice, etc), postiradiere, eozinofilia ereditara. Sindromul hipereozinofilic primar - defineste o eozinofilie cu valori inalte, peste 1500/mmc, de etiologie neprecizata, care persista peste 6 luni, asociata cu disfunctia unor organe, consecutiva infiltrarii lor cu eozinofile.

Eozinopenia ( scaderea numarului de granulocite eozinofile sub 200/mmc)- datorata hiperfunctiei CSR. Apare in stari de stres, posttraumatic, post interventii chirurgicale, dupa corticoterapie, vitamina C in doze mari si insulina, in cursul infectiilor acute cu neutrofilie, dupa expunere la frig, eforturi fizice mari. Aneozinofilia este patognomonica pentru febra tifoida.

Bazofilia ( cresterea numarului de granulocite bazofile peste 80/mmc)- apare in sindroame mieloproliferative, colite ulcerative, artrite reumatoide, urticarie, mixedem, postsplenectomie.

Bazopenia - scaderea numarului de granulocite bazofile nu are nici o semnificatie diagnostica, Apare in stari de stres, infectii acute, hipertiroidie, administrare de corticosteroizi.

Monocitoza ( cresterea numarului absolut de monocite peste 800/mmc) - apare ca urmare a stimularii productiei medulare de monocite de catre FSC-M. Se intalneste in boli infectioase, neoplazii, LES, sarcoidoza, sprue, colita ulceroasa, boli mieloproliferative, leucemii monocitare, limfoame maligne, mielom multiplu, neutropenii cronice, anemii hemolitice autoimune, unele reactii medicamentoase.

Monocitopenia ( scaderea numarului de monocite sub 150/mmc) - apare in aplazia medulara, leucemia cu tricholeucocite, dupa corticoterapie.

Limfocitoza ( cresterea numarului de limfocite peste 3000/mmc) - apare in modificari primare neoplazice ale seriei limfatice ( leucemia limfocitar cronica, limfoame maligne) ca limfocitoza reactiva ( infectii virale, boli infectioase acute si cronice, rahitism, hipertiroidie).

Limfocitopenia ( scaderea numarului de limfocite sub 1500/mmc) -apare ca urmare a productiei scazute ( imunodeficiente, malnutritie, dupa tratament citostatic, corticoterapie, boala hodgkin, mixedem, boala Cushing), prin modificari in circulatia limfocitelor, tranzitorii, mediate de cresterea glucosteroizilor endogeni ( stres) sau prin distructii crescute ( boli autoimune, infectii virale) ori pierderi ( rupturi sau fistule ale canalului toracic, enteropatii cu pierdere de proteine, insuficiente cardiace grave).

Plasmocitoza ( cresterea numarului de plasmocite peste 180/mmc)- este expresia unei sinteze crescute de imunoglobuline. Apare in boli infectioase, ciroza hepatica, alergia la penicilina, boala serului.

Modificari calitative ale elementelor seriei leucocitare

Defectele calitative ale neutrofilelor determina alterari ale fagocitozei. Anomaliile pot fi : congenitale ( deficitele lizei microbiene - granulomatoza cronica familiala, deficienta severa de G-6-PD, deficienta de MPO din granulatiile neutrofile si monocite; anomalii de structura celulara - sindromul Chediak-Higasi, anomalia Adler, anomalia Pelger-Huet, anomalia May-Hegglin, deficitul de adeziune leucocitara I) sau dobandite ( defecte intrinseci ale neutrofilului - in leucemiile acute si cronice, HPN, sindromul leucocitelor lenese; defecte extrinseci neutrofilului - diabet zaharat, uremie, mielom multiplu, arsuri severe)

Disfunctii ale monocitelor si macrofagelor

apar in osteopetroza ( deficit izolat al osteoclastelor, cu diminuarea resorbtiei osoase si formarea " oaselor de marmura"), boala granulomatoasa cronica, sindromul Chediak-Higashi, candidioza mucocutanata diseminata, terapia cu glucocorticoizi, fumatul.

SINDROAME MIELODISPLAZICE (SMD)

Sindroamele mielodisplazice (stări preleucemice) sunt afecţiuni clonale ale celulei stem caracterizate prin citopenii periferice cu măduvă hiper- sau normocelulară, cu semne de dishematopoieză uni- sau multilineară şi frecvente anomalii cromozomiale.

Factori de risc implicaţi în apariţia SMD: factori genetici şi constituţionali: sindromul Down, anemia Fanconi, boala

von Recklinghausen; iradierea cu doze mari sau repetate de radiaţii ionizante ( raze X sau

gamma); substanţe chimice sau medicamentoase : benzen, agenţi alchilanţi; aplazia medulară tratată cu imunosupresoare, neutropenia congenitală

tratată cronic cu G-CSF. SMD sunt tulburări clonale dobândite, rezultând ca urmare a

transformării neoplazice a CSP, cu afectarea în special a celulei stem orientate mieloid (rar a celor limfoide), care suferă o tulburare profundă a proceselor de maturare şi diferenţiere celulară, cu hematopoieză ineficientă prin hiperapoptoză şi o producţie inadecvată de celule sanguine mature cu modificări displazice.

SMD pot fi primare şi secundare (terapiei citostatice, imunosupresoare , induse de factori ocupaţionali şi de mediu, HIV).

Leucemiile Leucemiile sunt afecţiuni maligne

clonale, caracterizate prin proliferarea nelimitată de leucocite anaplazice, cu aberaţii cromozomiale, având caracter invadant şi infiltrativ la nivelul măduvei osoase hematogene şi teritoriilor extramedulare. Leucemiile pot fi acute sau cronice.

LEUCEMIA INTRODUCERE Atat cele cronice, cat si cele acute se clasifica functie de

linia celulara predominant proliferativa: Daca linia celulara predominanta apartine seriei mieloide

este vorba despre o leucemie mielocitara (denumita, uneori si leucemie granulocitara)

Daca linia celulara predominanta apartine seriei limfoide este vorba despre o leucemie limfocitara

Prin urmare, exista patru tipuri majore de leucemie Leucemia mieloida acuta (Acute Mielocytic leukemia –

AML)- care include mieloblasti, promielocite, monocite, mielomonocite, eritrocite si megakariocite)

Leucemia Limfocitara Acuta (Acute lymphocytic leukemia – ALL) care include celule T , B si celule NK (Natural Killer cell- Null cell)

Leucemia Mielocitara Cronica (Chronic myelocytic leukemia – CML) – care include myelocite si mielomonocite)

LEUCEMIA INTRODUCERE Leucemia Limfocitara Cronica (Chronic lymphocytic

leukemia – CLL) – care include plasmocite {mielom multiplu}, celule paroase, prolimfocite, large granular cell lymphocytic, Sezary’s syndrome, and circulating lymphoma)

Etiologie – cauza exacta este frecvent necunoscuta, dar se cunosc factori predispozanti:

Factori ai gazdei Some individuals have an inherited increased predisposition

to develop leukemia There is an increased incidence in those with an inherited

tendency for chromosome fragility or abnormality or those with increased numbers of chromosomes (such as Down’s syndrome). Many of these diseases are characterized by chromosomal translocations.

Leucemia Introducere Incidenta crescuta la cei cu imunodeficiente

ereditare. Incidenta crescuta la cei cu disfunctii

medulare cronice cum ar fi boli mieloproliferative, sindr mielodisplazice, anemia aplastica, hemoglobinuria paroxistica nocturna.

Factori de mediu: Expunere radiatii ionizante Expunere la mutagene chimice si anumite

subst medicam Infectia virala

LEUCEMIA INTRODUCERE Incidenta

Acute leukemias can occur in all age groups ALL (Acute Lymphoblastic Leukemia) is more

common in children AML (Acute Myeloid Leukemia) is more common

in adults Chronic leukemias are usually a disease of

adults CLL (Chronic Lymphocytic Leukemia) is extremely

rare in children and unusual before the age of 40 CML (Chronic Myeloid Leukemia) has a peak age

of 30-50

LEUCEMIA INTRODUCERE Comparatie lecucemie acuta vs cronica: Acute ChronicVarsta all ages usually adultsDebut Clinic sudden insidiousEvolutie (netratata) 6 mo. or less 2-6 yearsCelule Leucemice immature >30% blasts more mature

cellsAnemia prominent mildThrombocytopenia prominent mildNr leucocite variable increasedLimphadenopaie mild present;often prominentSplenomegalie mild present;often prominent

LEUCEMIA INTRODUCERE Leucemia Acuta –

Este rezultatul: Transformarii maligne a celulei stem conducand la

proliferare neregulata si Oprind maturarea la stadiul de blasti primitivi.

Remember that a blast is the most immature cell that can be recognized as committed to a particular cell line.

Aspecte clinice Proliferare Leucemica, accumulare si invasizie a

tesuturilor normale, incluzand ficatul, splina, ggl limfatici, sist nerv central, pilele.

Posibil un mediator umoral secretat de celulele leucemice ar inhiba proliferarea celulelor normale.

LEUCEMIA INTRODUCERE Insuficienta maduvei si hematopoezei

normale poate conduce la pancitopenie si moarte prin hemoragii si infectii.

Evaluare de laborator Diagnosticul de laborator de bazeaza pe

doua aspecte Aparitia unei cresteri semnificative de

elemente imature in maduva incluzand blasti, promielocite, promonocite (>30% blasti este semn diagnostic)

Identificarea liniei celulare leucemice

LEUCEMIA INTRODUCERE Sangele periferic:

Anemia (normocroma, normocitara) Scadere plachete Numar leucocite Variabil

The degree of peripheral blood involvement determines classification:

Leukemic – increased WBCs due to blasts Subleukemic – blasts without increased WBCs Aleukemic – decreased WBCs with no blasts

Clasificarea celulelor imature implicate trebuie facuta prin:

LEUCEMIA INTRODUCERE Morfologie – an experienced morphologist

can look at the size of the blast, the amount of cytoplasm, the nuclear chromatin pattern, the presence of nucleoli and the presence of auer rods (are a pink staining, splinter shaped inclusion due to a rod shaped alignment of primary granules found only in myeloproliferative processes) to identify the blast type:

AML – mieloblastul este un blast mare cu cantitate moderata de citoplasma, cromatina fina, nucleoli proeminenti. 10-40% dintre mieloblasti contin corpi Auer.

Myeloblast cu corpi Auer

LEUCEMIA INTRODUCERE ALL (Leuc Limfoblastica acuta) – in contrast cu

cea mieloblastica, th limfoblastul este un blast mic cu insuficienta citoplasma, cromatina densa, nucleoli nedistinctivi si fara corpii Auer.

Limfoblast

LEUCEMIA INTRODUCERE

Citocimia – ajuta la clasificarea liniei celulare leucemice (mieloida versus limfoida)

Mieloperoxidaza – se afla in granulatiile primare ale cel granulocitare incepand cu stadiul de blast tarziu. Monocitele pot fi slab positive.

Negru Sudan Negru Sudan coloreaza

phospholipidele, grasimile neutre si sterolii aflati in granulele primare si secundare ale celulei granulocitare si mai putin in lizozomii monocitelor. Rareori apare positivitate in celulele limfoide

Esteraza Nonspecifica

Esteraza Nespecifica– este utilizata pentru a identifica cel monocitare care sunt difuz pozitive. Limfocitele T pot avea colorari focale

Fosfataza Acida Fosfataza Acida poate fi gasita in

mieloblasti si limfoblasti. Limfocitele T au un nivel cresut de fosfataza acida si pot fi utilizate pentru a ajuta diagnosticul leucemiei acute T limfocitare.

Fosfataza alcalina leucocitara

Fosfataza alcalina leucocitara– este localizata in granulele tertiare ale neutrofilelor segmentate si in metamielocite. Scorul FAL este determinat numarand 100 neutrofile mature scorand de la 0 la 5 fiecare celula. The total LAP score is calculated by adding up the scores for each cell.

Fosfataza alcalina leucocitara

LEUCEMIA INTRODUCERE Markerii imunologici (imunofenotiparea) – sunt utilizati

mai ales pentru lymphocytes, i.e., pentru determinarea liniilor B sau T. Se bazeaza pe anticorpii anti markeri specifici de suprafata. Constituie ceea ce numim anticorpi primari . Fluorescently labeled antibody (secondary antibody) against the primary antibody is added and allowed to react and then unbound secondary antibody is washed away. The cells are then sent through a flow cytometer that will determine the number of cells that have a fluorescent tag and which are thus positive for the presence of the surface marker to which the primary antibody was made. In a direct assay, the primary antibody is fluorescently labeled.

Direct versus indirect labeling of antigens

Flow cytometer

Deoxytidyl transferaza terminala Este o DNA polimeraza unica

prezenta in celulele stem si in precursorii B si T limfoizi celulari. Niveluri crescute se gasesc in 90% din leucemia limfoblastica. It can also be detected using appropriate antibodies and flow cytometry.

LEUCEMIA INTRODUCERE Citogeneza – studiile citogenetice pot fi cum

utilizate pentru diagnostic si pentru prognosticul afectiunilor hematologice maligne.

Many leukemias (and lymphomas) are characterized by specific chromosomal abnormalities, including specific translocations and aneuploidy. The specific type of malignancy can be identified based on the specific abnormality or translocation. These may be identified by

Looking at the karyotypes of the chromsomes from the abnormal cells

DNA based tests – these tests are very useful for following the course of the disease

A normal karyotype is usually associated with a better prognosis.

Chromosomal translocation

Chromosome karyotyping

Leucemiile acute Leucemia limfoblastica acuta

They may be classified on the basis of the cytological features of the lymphoblasts into;

L1 - This is the most common form found in children and it has the best prognosis. The cell size is small with fine or clumped homogenous nuclear chromatin and absent or indistinct nucleoli. The nuclear shape is regular, occasionally clefting or indented. The cytoplasm is scant, with slight to moderate basophilia and variable vacuoles.

ALL-L2Leucemia limfoblastica acuta:L2 – This is the most frequent ALL found in adults. The cell size is large and heterogenous with variable nuclear chromatin and prominent nucleoli. The nucleus is irregular, clefting and indented. The cytoplasm is variable and often moderate to abundant, the basophilia is variable and may be deep, and vacuoles are variable.

Leucemiile acute L3 – This is the rarest form

of ALL. The cell size is large, with fine, homogenous nuclear chromatin containing prominent nucleoli. The The nucleus is regular oval to round. The cytoplasm is moderately abundant and is deeply basophilic and vacuolated.

Leucemiile acute ALL may also be classified on the

basis of immunologic markers into: Early pre-B ALL Pre-B ALL B ALL T ALL Null or unclassified ALL (U ALL) - lack B

or T markers and may be the committed lymphoid stem cell)

B cell maturation

T cell maturation

Leucemiile acute Incidenta – ALL este caracteristica

copiilor mici (2-5 ani), dar poate aparea si la adulti

Clinica– pancitopenia cu astenia, paloare, febra, scadere in greutate, iritabilitate, infectii, anorexie, dureri osoase, sangerari.

L1 occurs in children, L2 in adults, and L3 is called Burkitts leukemia

Leucemiile acute Prognoza – varsta, nr de leucocite si tipul de

celula sunt cei mai importanti indicatori de prognostic

Patients younger then 1 and greater than 13 have a poor prognosis

If the WBC count is < 10 x 109/L at presentation, the prognosis is good; If the WBC count is > 20 x 109/L at presentation the prognosis is poor

T cell ALL (more common in males) has a poorer prognosis than any of the B cell ALLs which have a cure rate of 70%

Leucemiile acute Acute leukemias with mixed lineage –

there are occasionally acute leukemias that are biphenotypic and display phenotypes for two different lineages B lymphoid/myeloid T lymphoid/myeloid B/T lymphoid Myeloid/Natural killer A rare trilineage leukemia has also been

seen (was B/T lymphoid/myeloid!)

Leucemiile acute Leucemia mieloblastica acuta (sau

Leucemia granulocitara acuta) – clasificarea se bazeaza pe Morfologia blastilor medulari Gradul maturarii celulare Reactii citochimice Imunofenotipare AML is divided into 7 different classifications:

M1 – myeloblastic without maturation The bone marrow shows 90% blasts and < 10%

promyelocytes The disease occurs in older adults

AML – M1 Note the myeloblasts and the auer

rod:

Leucemiile acute M2 – myeloblastic with maturation

The bone marrow shows 30-89% blasts and > 10% promyelocytes;

This is characterized by an 8,21 chromosomal translocation

This occurs in older adults M3 – hypergranular promyelocytic

This form of AML has a bone marrow with >30% blasts Is more virulent than other forms Occurs with a medium age of 39 The WBC count is decreased Treatment causes a release of the granules and may

send the patient into disseminated intravascular coagulation and subsequent bleeding

It is characterized by a 15,17 chromosomal translocation

AML – M2 Note myeloblasts and

hypogranulated PMNs:

AML – M3 Note hypergranular

promyelocytes:

Leucemiile acute M3m – hypogranular promyelocytic –

The bone marrow has > 30% blasts The WBC count is increased. Like the M3 type, treatment causes a release of the

granules and may send the patient into disseminated intravascular coagulation and subsequent bleeding and

It is characterized by a 15,17 translocation M4 – acute myelomonoblastic leukemia

Both myeloblasts and monoblasts are seen in the bone marrow and peripheral blood

Infiltration of extramedullary sites is more common than with the pure granulocytic variants

AML – M3m Note hypogranular promyelocytes:

AML – M4 Note monoblasts and

promonocytes:

Leucemiile acute M5 – acute monoblastic leukemia

>80% of the nonerythroid cells in the bone marrow are monocytic

There is extensive infiltration of the gums, CNS, lymph nodes and extramedullary sites

This form is further divided into M5A - Poorly differentiated (>80% monoblasts) M5B - Well differentiated (<80% monoblasts)

M6 – erythroleukemia This is rare and is characterized by a bone marrow having a

predominance of erythroblasts It has 3 sequentially morphologically defined phases;

Preponderance of abnormal erythroblasts Erythroleukemia – there is an increase in both erythroblasts

and myeloblasts Myeloblastic leukemia – M1, M2, or M4

Anemia is common

AML – M5A Note monoblasts:

AML-M5B Note monoblasts, promonocytes,

and monocytes:

AML – M6 Note M1 type monoblasts

Leucemiile acute M7 - Acute megkaryoblastic leukemia

This is a rare disorder characterized by extensive proliferation of megakaryoblasts, atypical megakaryocytes and thrombocytopenia

Tratamentul leucemiilor – Are doua scopuri:

Eradicarea masei celulare leucemice Actiuni de suport

Except for ALL in children, cures are not common but complete remission (absence of any leukemia related signs and symptoms and return of bone marrow and peripheral blood values to within normal values) is

Leucemiile acute Exista patru tipuri generale de terapie

Chimioterapia – usually a combination of drugs is used

Transplantul de maduva Radioterapia Immunoterapia – stimulate the patients

own immune system to mount a response against the malignant cells