INTRODUCTION
The tra nsfe rrin re c e pto r, a g lyc o pro te in present o n the surface o f mo st cells, is respo nsible fo r binding transferrin during the endo cyto sis o f iro n. The so luble fo rm o f the recepto r (sTfR) was initially described by Ko hg o et al and is derived fro m the cleavag e o f the extracellular po rtio n o f the recepto r.1 The expressio n o f sTfR is reg ulated by the availability o f iro n. Thus, an iro n deficiency rapidly induces synthesis o f the recepto r and an excess o f iro n suppresses its synthesis.1 -3 Hig h levels o f sTfR ha ve b een repo rted in immune hemo lytic anemia, hereditary sphero cyto sis, Hb
H disease,
β
thalassemia intermedia and sicklecell syndro mes. The repo rted co rrelatio n between the deg ree o f hemo lysis and sTfR levels suppo rts the hypo the sis tha t the de te rmina tio n o f sTfR co ncentratio ns co uld be a useful indicato r o f the deg ree o f erythro cyte expansio n.4 -6
Sing ha l e t a l5 a na lyz e d the c linic a l sig nific a nc e o f sTfR le ve ls in pa tie nts with S hemo g lo bino pathy and fo und that there was no a ltera tio n in the serum c o nc entra tio ns o f this recepto r during infectio us situatio ns o r painful crises. Ho wever, they o bserved hig h sTfR levels in patients with hypersplenism, which returned to no rma l va lue s a fte r sp le ne c to my. The se
Soluble transfe rrin re ce ptor in sickle
ce ll dise ase s: corre lation with sple e n function
Department of Clinical Pathology, School of Medical Sciences,
Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
Helena Zerlotti Wolf Grotto Elza Miyuki Kimura Márcia Victor Carneiro
ABSTRACT
O bjective: To co rrelate spleen functio n with so luble transferrin recepto r (sTfR) levels and red cell ferritin (RCF) values in patients with sickle cell diseases.
Design: Pro spective study.
Loca tion: University Ho spital, Scho o l o f Medical Sciences, State University o f Campinas; a tertiary ho spital.
Pa rticipa nts: 6 0 patients with sickle cell diseases, in a steady state, who had no t received blo o d transfusio ns fo r 3 mo nths; 2 8 no rmal individuals with no clinical o r
labo rato ry sig ns o f anemia.
M ea surements: Determinatio n o f serum iro n, transferrin iro n-binding capacity, serum ferritin, RCF and sTfR. Evaluatio n o f spleen functio n: erythro cytes with pits were quantified.
Results: Patients with sickle cell anemia had sTfR levels significantly higher than in no rmal individuals o r tho se with HbSC (p=0 .0 0 0 1 ) and there was an inverse co rrelatio n between sTfR and fetal Hb (p=0 .0 0 1 6 ). RCF values were significantly higher in sickle cell anemia patients than in no rmal individuals o r tho se with HbSC (p=0 .0 0 0 1 ), and there was a co rrelatio n between RCF and pitted erythro cytes (p=0 .0 5 1 2 ).
Conclusion: The asso ciatio n between sTfR and fetal Hb co nfirms the co ntributio n o f fetal Hb to impro ving the hemo lytic state by minimizing the co nsequent reactive erythro cyte expansio n. Hig h sTfR levels are no t related to the deg ree o f spleen functio n deficiency seen in sickle cell disease patients. The deficiency in the exo cyto sis pro cess o f the spleen o ccurring in sickle cell anemia patients may co ntribute to their accumulatio n o f RCF.
Key w ords: Hemo g lo bino pathies. Pitted erythro cytes. Red cell ferritin. So luble transferrin recepto r. Sickle cell disease.
c ha ng e s mo st like ly re fle c t the e xte nt o f e ry thro c y te e x p a nsio n b e fo re a nd a fte r sp le ne c to my. In ind ivid ua ls w ith sic kle c e ll d ise a se , re p e a te d infa rc tio ns re sulting fro m va sc ula r o c c lusio n b y e rythro c yte s le a d s to deficient functio ning o f the spleen, and hence, to a g reater susceptibility to infectio ns.7 Deficient functio ning o f the spleen may also be related to hig h levels o f red cell ferritin (RCF) in patients w ith he mo g lo b ino p a thie s, p ro b a b ly d ue a deficiency in the exo cyto sis o f excess ferritin, a pro cess which o ccurs preferentially in the spleen.8 To investig ate the relatio n between sTfR le ve ls a nd the d e g re e o f sp le e n func tio n deficiency, we have examined the co rrelatio n between the serum co ncentratio ns o f the sTfR and the numb e r o f e rythro c yte s w ith me mb ra ne irre g ula ritie s (“ p its” ) in p a tie nts w ith S hemo g lo bino pathy. Pitted erythro cytes are a well-established indicato r o f spleen functio n.9
METHODS
Pa tie nts. Sixty p a tie nts w ith sic kle c e ll diseases seen at the Hemo centro -Unicamp were studied. Fo rty-three had sickle cell anemia (SS), seven ha d S
β
tha la ssemia (Sβ
tha l), nine ha d he mo g lo b in SC d ise a se a nd o ne w a s C C ho mo zyg o us (SC+CC g ro up). All patients were adults in a steady state and had no t received a blo o d transfusio n fo r 3 mo nths. They all g ave their info rmed co nsent to participate in this study w hic h w a s a p p ro ve d b y the ho sp ita l Ethic s Co mmittee. Twenty-eig ht no rmal individuals (N ) with no clinical o r labo rato ry sig ns o f anemia served as the co ntro l fo r this study.Hemato lo g ical pro file. The hemato lo g ical mea surements were o b ta ined using a Co b a s Arg o s (ABX - Ho riba, France) analyzer. The levels o f fetal hemo g lo bin (HbF) were determined by an alkaline denaturatio n metho d.1 0
TABLE I - Iron sta tus of the va rious groups studied
N SS SβThal† SC+CC
Parameters n mean SD n mean SD n mean SD n mean SD SI 2 8 8 8 .1 8 3 0 ,0 4 3 1 2 9 .5 3 * 5 9 .0 7 1 3 7 .1 4 5 9 .4 1 0 1 0 5 .7 2 7 .8 5
(µg/ dL) (3 8 -1 5 5 ) (4 1 -2 5 4 ) (7 5 -2 5 3 ) (6 5 -1 4 4 )
TIBC 2 8 3 0 0 .9 3 5 9 .1 4 3 2 8 7 .1 4 6 9 .7 7 2 9 6 .7 1 5 .7 1 1 0 3 0 3 .6 3 5 .0
(µg/ dL) (2 1 8 -3 9 4 ) (1 7 4 -4 5 4 ) (2 4 5 -3 8 9 ) (2 4 2 -3 6 4 )
SF 2 8 6 3 .2 3 4 6 .9 4 3 6 0 8 .9 5 * 1 1 7 1 .5 7 9 8 5 .7 9 1 2 4 9 1 0 2 9 1 .1 3 8 5 .7
(ng/ ml) (1 1 -1 6 2 ) (1 2 -5 8 7 0 ) (3 6 -3 0 2 0 ) (3 6 -1 2 8 0 )
RCF 2 8 1 1 .4 7 7 .4 8 4 1 5 0 .2 9 * 4 5 .9 7 5 4 .7 6 3 7 .1 1 0 1 8 .7 8 * * 1 0 .9
(a tt/ cell) (3 .2 2 -3 5 .3 ) (9 .5 8 -2 1 3 .3 ) (8 .7 -1 2 8 .4 ) (2 .8 -3 3 .3 )
sTfR 2 8 2 .1 0 0 .3 7 4 2 1 3 .6 9 * 5 .2 3 5 1 3 .0 4 3 .9 5 9 6 .5 8 * / * * 1 .3 6
(µg/ ml) (1 .3 -2 .8 3 ) (2 .5 4 -2 9 .4 4 ) (8 .8 8 -1 7 .6 ) (4 .7 6 -8 .0 8 ) [(rang e)]
SI: serum iro n; TIBC: transferrin iro n binding capacity; SF: serum ferritin RCF: red cell ferritin; sTfR: so luble transferrin recepto r
Evaluatio n o f the iro n state. Determinatio n o f serum iro n (SI) and the transferrin iro n-binding capacity (TIBC) was do ne with a Mira Plus Co bas analyzer (Ro che - Switzerland) using Unimate 5 Iro n and Unimate 7 UIBC kits (Ro che Diag no stic Systems - Switzerland). Serum ferritin (SF) was determined by a fluo ro metric immuno enzymatic test (Stratus-Dade Internatio nal Inc. - Miami, USA) and hemo lyzed RCF levels were quantified by a ra p id fre e z e -tha w me tho d fo llo w e d b y a fluo ro me tric immuno e nz yma tic a ssa y.1 1 The serum co ncentratio n o f sTfR was measured by an immuno enzymatic technique (Q uantikine R&D Systems - USA). The samples fro m SS and S
β
thal patients were diluted 1 :4 0 0 prio r to assaying . All samples were kept at -8 00C.Evaluatio n o f spleen functio n. Erythro cytes with pits were quantified by interference co ntrast micro sco py.1 2
Sta tistic a l me tho d s. Fo r c o mp a riso n b e tw e e n the g ro up s, the M a nn-W hitne y o r Kruskal-W allis tests were emplo yed fo r variance analysis and the Spearman co rrelatio n co efficient te st w a s use d fo r a sse ssing the a sso c ia tio n between variables, with level o f sig nificance set at <0 .0 5 .
RESULTS
Eva lua tio n o f the sTfR levels. The serum co ncentratio ns o f sTfR were statistically different when the N and SS, N and SC+CC, and SS and SC+CC g ro ups were co mpared (p<0 .0 5 ) (Table I). In the S
β
thal g ro up, o nly five patients we re e va lua te d fo r sTfR le ve ls, a ll o f who m sho wed extremely hig h values (Fig ure 1 ). Two SS individuals had labo rato ry pro files co mpatible w ith iro n d e fic ie nc y a ne mia : mic ro c y tic hypo chro mic anemia, reduced levels o f SI and SF, hig h TIBC, transferrin saturatio n (TS) <1 5 % a nd a no rma l le ve l o f Hb A2. The sTfRco ncentratio ns fo r these patients did no t differ fro m tho se o bserved in o ther members o f the same g ro up. Ho wever, the recepto r/ ferritin ratio was >5 0 0 in bo th cases, a finding co mpatible w ith iro n d e p le tio n.2 A sig nific a nt inve rse c o rre la tio n b e twe e n sTfR le ve ls a nd the Hb F
co ncentratio n was seen in SS patients, but no t in the SC+CC g ro up (Table III).
sTfR levels and spleen functio n. All patients with sickle cell diseases presented so me deg ree o f spleen functio n deficiency based o n ho w much abo ve no rmal values (>2 %) the pitted erythro cyte percentag e was.1 2 The deg ree o f variability in this parameter was co nsiderable (Table II). N o co rrelatio n was o bserved between the number o f pitted erythro cytes and the sTfR values. To determine whether an elevated RCF co uld have resulted fro m a malfunctio n in spleen exo cyto sis capacity, we examined the co rrelatio n between the number o f pitted erythro cytes and RCF levels. A po sitive co rrelatio n was o bserved (p=0 .0 5 1 ) between these two variables in SS patients, but no t in SC o r CC individuals (Table III).
DISCUSSION
W e fo und a sig nific a nt inc rea se in sTfR le ve ls in a ll o f the p a tie nts stud ie d , w ith sig nificantly hig her levels in the SS g ro up than in the SC+CC g ro up. These finding s ag ree with tho se in the literature.5 ,1 4 -1 6
The tra nsfe rrin re c e pto r is a me mb ra ne g lyc o p ro te in re sp o nsib le fo r inte rna liz ing transferrin in the erythro cyte cell. Fo llo wing the fo rmatio n o f a vesicle, fusio n o f the endo so mes a nd a c idific a tio n, iro n is re le a se d fo r he me synthesis, while the recepto r returns to the cell me mb ra ne a nd the a p o tra nsfe rrin to the
TABLE 2 - Eva lua tion of spleen function - % of
erythrocytes w ith pits
G ro up n mean SD (rang e)
N 2 8 0 .6 6 0 .5 4 (0 to 1 .8 )
SS 4 3 2 6 .5 1 7 .9 8 (5 to 4 1 .8 )
Sßtha l 7 2 1 .7 4 1 5 .6 8 (2 .9 to 4 4 .6 )
plasma.4 ,1 7 The principal facto rs reg ulating the density o f these recepto rs in the cells are the quantity o f iro n, stimulatio n by erythro po etin and the cell cycle.1 8 The sTfR is fo und in human plasma and appears be a truncated fo rm o f the tissue recepto r g enerated by a pro teo lytic mechanism that is still no t well understo o d.1 7 It has been sug g ested that the serum co ncentratio n o f sTfR may be an accurate indicato r o f iro n depletio n, e sp e c ia lly in d isting uishing b e tw e e n iro n-d e p riva tio n a ne mia a nn-d c hro nic n-d ise a se anemia.1 9 In situatio ns where erythro po iesis is threatened, such as in aplastic anemia, the sTfR levels are sig nificantly lo wer than in patients with iro n deficiency anemia, hemo lytic anemia o r in no rmal individuals.2 0
In hemo glo bino pathy, an elevatio n in sTfR le ve ls ma y re sult fro m the hig h d e g re e o f e rythro c yte e xp a nsio n fo und in this illne ss. Co rro bo rating this hypo thesis is the demo nstratio n
o f an inverse relatio nship between sTfR levels and the age o f the patients, as well as between sTfR levels and HbF rates.5 Serjeant et al1 6 studied the po ssible determinants o f HbF levels in SS patients in Jamaica and fo und that HbF had no influence o n sTfR levels, altho ugh there was a tendency fo r sTfR co ncentratio ns to decrease as the Hb level increased. In o ur subjects, there was an inverse co rrelatio n between the sTfR and HbF levels in the SS, but no t the SC+CC gro up. This negative co rrelatio n in SS patients suppo rts the hypo thesis that high HbF levels inhibit sickling and hemo lysis, thereby minimizing erythro po ietic activity.5
The results o btained in the present study have co nfirmed tho se repo rted in the literature, indicating that patients with sickle cell anemia have so me deg ree o f spleen functio n deficiency.7 W hilst there may be g reat variability in the pitted erythro cyte co unts in these cases, they are always hig her than in no rmal individuals.1 2 ,2 1 ,2 2 In no ne
TABLE 3 - Correla tion betw een va ria bles
Variables G ro up n Co rrelatio n co efficient (r) p value
sTfR x HbF SC+CC 9 0 .4 6 6 7 0 .2 0 5 4
SS 4 1 -0 .4 7 6 5 0 .0 0 1 6 *
sTfR x PITS SC+CC 9 -0 .2 8 3 3 0 .4 6 0 0 SS 4 2 -0 .0 5 5 0 0 .7 2 9 2
sTfR x RCF SC+CC 9 0 .3 0 0 0 0 .4 3 2 8
SS 4 0 -0 .1 2 9 8 0 .4 2 4 8
RCF x PITS SC+CC 9 0 .0 5 4 6 0 .8 8 1 0
SS 4 1 0 .3 0 6 6 0 .0 5 1 2
sTfR x HbF SC+CC 9 0 .4 6 6 7 0 .2 0 5 4
SS 4 1 -0 .4 7 6 5 0 .0 0 1 6 *
sTfR x HbF SS, RPI<2 1 1 -0 .8 7 6 7 0 .0 0 0 4 * SS, RPI>3 2 3 -0 .2 3 4 7 0 .2 8 1 0
RCF x SF SS 4 1 0 .4 7 7 4 0 .0 0 1 6 *
SC+CC 1 0 -0 .4 1 2 8 0 .2 2 9 1
TS x RCF SS 4 1 0 .3 6 4 5 0 .0 1 9 1 *
SC+CC 1 0 0 .8 1 8 2 0 .0 0 3 8 * statistically sig nificant
HbF: fetal hemo g lo bin RCF: red cell ferritin TS: transferrin saturatio n
o f o ur patients was there any spleen hyperactivity, no r had any o f them underg o ne splenecto my. O ur analysis therefo re refers to sTfR behavio r in p a tie nts w ith hyp o a c tive sp le e ns in w ho m erythro po ietic activity was no t exacerbated. In these cases, the abno rmally high sTfR values result fro m chro nic hemo lysis and fro m erythro po ietic expa nsio n a t the level o f the ma rro w with a g reater release o f red cells into the circulatio n. Cro sby,2 3 co mmenting o n hemato po iesis in the human spleen, indicated that in diseases that require a hig h reactive pro ductio n o f red blo o d c e lls b y the b o ne ma rro w, sma ll c luste rs o f hemato po ietic cells may be fo und in the spleen. This po ssibility may be co nsidered to make so me co ntributio n to the elevatio n o f sTfR levels in sickle cell disease patients.
In o ur study, hig h RCF levels were seen in SS a nd S
β
tha l p a tie nts; p a tie nts w ith C hemo g lo b ino pa thy ha d va lues a ppro xima ting tho se o f no rmal individuals. The po ssible causes o f hig h RCF in hemo g lo bino pathy include g reater capture o f iro n by erythro cyte tissue, inadequate utilizatio n o f iro n in Hb synthesis, an increase in apo ferritin synthesis subsequent to greater release o f iro n d ue to intra c e llula r d e na tura tio n, increased erythro cyte destructio n and deficiency in the pro cess o f exo cyto sis o r “ pitting ” resulting in the inefficient remo val o f excess ferritin by the spleen.8 ,9 ,1 3W e studied the latter aspect by quantifying the number o f pitted erythro cytes. Altho ug h the c o rrela tio n c o effic ient wa s no t sig nific a nt, its value sug g ests a po ssible co ntributio n o f spleen func tio n d e fic ie nc y to RC F a c c umula tio n in patients with sickle cell anemia.
W e co nclude that patients with sickle cell diseases sho w impo rtant alteratio ns relevant to sTfR behavio r. In SS patients, the asso ciatio n between sTfR and HbF co nfirms the co ntributio n o f Hb F to imp ro ving the he mo lytic sta te b y minimizing the co nsequent reactive erythro cyte expansio n. RCF levels as an indicato r o f iro n accumulatio n have a limited value and need to b e a na lyz e d to g e the r w ith o the r p e rtine nt la b o ra to ry p a ra me te rs. Sp le e n func tio n
deficiency apparently do es no t interfere with o r partic ipa te in a ltera tio ns o f iro n meta b o lism, a ltho ug h d e fic ie nc ie s fro m “ p itting ” c o uld co ntribute to a reduced ability to remo ve ferritin fro m erythro cytes.
REFERENCES
1. Ko hgo Y, Nishisato T, Ko ndo H, Tsushima N, Niitsu Y. Circulating
transferrin recepto r in human serum. Br J Haemato l 1986;64:277-81.
2. Skikne BS, Flo we rs CH, Co o k JD. Se rum transfe rrin re ce pto r: a
quantitative measure o f tissue iro n deficiency. Blo o d 1990;75:1870-6.
3. Baynes RD, Co o k JD, Bo thwell TH, Friedman BM, Meyer TE. Serum
transferrin recepto r in hereditary hemo chro mato sis and African sidero sis. Am J Hemato l 1994;45:288-92.
4. Huebers HA, Beguin Y, Po o trakul P, Einspahr D, Finch CA. Intact
trans fe rrin re c e p to rs in hum an p las m a and the ir re latio n to erythro po iesis. Blo o d 1990;75:102-7.
5. Singhal A, Co o k JD, Skikne BS, Tho mas P, Serjeant B, Serjeant G.
The clinical significance o f serum transferrin recepto r levels in sickle cell disease. Br J Haemato l 1993;84:301-4.
6. Galanello R, Barella S, Turco MA, et al. Serum erythro po ietin and
erythro po iesis in high- and lo w-fetal hemo glo b in ß-thalassemia intermedia patients. Blo o d 1994;83:561-5.
7. Pearso n HA, Gallagher D, Chilco te R, et al. Develo pmental pattern o f
splenic dysfunctio n in sickle cell diso rders. Pediatrics 1985;76:392-7.
8. Jac o b s A, Pe te rs SW, Bau m in g e r ER, Eike lb o o m J, O fe r S,
Rachmilewitz EA. Ferritin co ncentratio n in no rmal and abno rmal erythro cytes measured by immuno radio metric assay with antibo dies to he art and sple e n fe rritin and Mö ssb aue r spe ctro sco py. Br J Haemato l 1981;49:201-7.
9. Ro gers DW, Serjeant BE, Serjeant GR. Early rise in “pitted” red cell
co unt as a guide to susceptibility to infectio n in childho o d sickle cell anaemia. Arch Dis Child 1982;57:338-42.
10. Pembrey ME, MacWade P, Weatherall DJ. Reliable ro utine estimatio n
o f small amo unts o f fo etal haemo glo bin by alkali denaturatio n. J Clin Patho l 1972;25:738-40.
Figure 1 - Distribution of STfR levels in sickle cell diseases.
11. Peters SW, Jaco bs A, Fitzsimo ns E. Erythro cyte ferritin in no rmal subjects and patients with abno rmal iro n metabo lism. Br J Haemato l 1983;53:211-6.
12. Gro tto HZW, Co sta FF. Pattern o f splenic phago cytic functio n in
Bra zilia n p a tie n ts with s ic kle c e ll d is e a s e . Re v Pa u l M e d 1992;110:262-6.
13. Bauminger ER, Co hen SG, Ofer S, Rach-Milevitz EA. Quantitative
studies o f ferritin-like iro n in erythro cytes o f thalassemia, sickle cell anemia and Hb Hammersmith with Mö ssbauer spectro sco py. Pro c Natl Acad Sci USA 1979;76:939-43.
14. Musto P, Lo mbardi G, Centra M, Mo do ni S, Caro tenuto M, DiGio rgio
G. So lub le transfe rrin re c e p to r in b e ta-thalassae m ia. Lanc e t 1993;342:1058.
15. Co o k JD, Skikne BS, Baynes RD. Serum transferrin recepto r. Annu
Rev Med 1993;44:63-74.
16. Serjeant G, Serjeant B, Stephens A, Ro per D, Higgs D, Beckfo rd M,
Co o k J, Tho mas P. Determinants o f haemo glo bin level in steady-state ho mo zygo us sickle cell disease. Br J Haemato l 1996;92:143-9.
17. Beguin Y. The so luble transferrin recepto r: bio lo gical aspects and
c linic al use fulne ss as q uantitative m e asure o f e rythro p o ie sis. Haemato lo gica 1992;77:1-10.
18. Cazzo la M, Beguin Y. New to o ls fo r clinical evaluatio n o f erythro n
functio n in man. Br J Haemato l 1992;80:278-84.
19. Ferguso n BJ, Skikne BS, Simpso n KM, Baynes RD, Co o k JD. Serum
transferrin recepto r distinguishes the anemia o f chro nic disease fro m iro n deficiency anemia. J Lab Clin Med 1992;19:385-90.
20. Scherezenmeier H, No é G, Raghavachar A, Rich IN, Heimple H,
Kubanek B. Serum erythro po ietin and serum transferrin recepto r levels in aplastic anaemia. Br J Haemato l 1994;88:286-94.
21. Caspe r JT, Ko e the S, Ro de y GE, Thatche r G. A ne w me tho d fo r
stud ying sp le nic re tic ulo e nd o the lial d ysfunc tio n in sic kle c e ll disease patients and its clinical applicatio n: a brief repo rt. Blo o d 1976;47:183-8.
22. Sills RH. Splenic functio n in children with hemo glo bin SC and sickle
ß thalassemia. J Natl Med Asso c 1983;75:991-4.
23. Cro sby WH. Hemato po iesis in the human spleen. Arch Intern Med
1983;143:1321-2.
Ack now ledgem ents: The autho rs g ratefully ackno wledg e the technical assistance o f Dr. Vera SC Mo raes e Miss Co ncilia G arcia.
Helena Zerlotti W olf Grotto
MD, PhD. Department o f Clinical Patho lo g y, Scho o l o f Medical Sciences, State University o f Campinas (UN ICAMP), Campinas, SP, Brazil
Elza M iyuk i Kim ura
Bio lo g ist, Department o f Clinical Patho lo g y, Scho o l o f Medical Sciences, State University o f Campinas (UN ICAMP), Campinas, SP, Brazil
M á rcia V ictor Ca rneiro
Bio lo g ist, Department o f Clinical Patho lo g y, Scho o l o f Medical Sciences, State University o f Campinas (UN ICAMP), Campinas, SP, Brazil
Sources of Funding: FAEP (G rant nº 0 0 2 5 / 9 5 ).
Conflict of interest: N o t declared.
La st received: 1 8 N o vember 1 9 9 8
Accepted: 8 January 1 9 9 9
Address for correspondence:
Helena Zerlo tti W o lf G ro tto Departamento de Pato lo g ia Clínica Esco la de Ciências Médicas, UN ICAMP
Cx Po stal 6 1 1 1 - CEP 1 3 0 8 1 -9 7 0 - Campinas/ SP - Brasil E-mail: g ro tto @ fem.unicamp.br
RESUMO
O bjetivo: Relacio nar a função esplênica co m o s níveis do recepto r so lúvel da transferrina (sTfR) e co m o s valo res da ferritina intra-eritro citária (RCF) em pacientes co m do enças falcifo rmes. Tipo de Estudo: Estudo pro spectivo . Loca l: Ho spital das Clínicas da Faculdade de Ciências Médicas da UN ICAMP, atendimento terciário . Pa rticipa ntes: 6 0 pacientes po rtado res de do enças falcifo rmes, na fase estável da do ença, sem transfusão de sangue no s último s 3 meses; 2 8 indivíduo s no rmais, sem sinais clínico s e labo rato riais de anemia. Va riá veis estuda da s: Determinação do ferro sérico , capacidade de lig ação do ferro à transferrina, ferritina sérica, RCFe sTfR. Avaliação da função esplênica: quantificação de hemácias co m “ pits” . Resulta dos:
Pacientes co m anemia falcifo rme: o s níveis de sTfR fo ram sig nificativamente mais elevado s do que no s indivíduo s no rmais e co m Hb SC (p=0 ,0 0 0 1 ); co rrelação inversa entre sTfR e Hb Fetal (p=0 ,0 0 1 6 ); valo res de RCF sig nificativamente mais elevado s do que no s indivíduo s no rmais e pacientes SC (p=0 ,0 0 0 1 ); co rrelação entre RCF e hemácias co m “ pits” (p=0 ,0 5 1 2 ).Conclusões:
A asso ciação entre sTfR e Hb Fetal co nfirma a co ntribuição da Hb Fetal na melho ra do quadro hemo lítico , o que,
