Fc receptor blockade in patients with refractory chronic immune thrombocytopenic purpura with anti-D IgG.
BACKGROUND
This is an evaluation of the treatment of 63 patients with chronic immune thrombocytopenic purpura (54 splenectomized and nine nonsplenectomized) with weekly doses of anti-D (IgG)-coated red blood cells (RBCs).


METHODS
All patients were given one 5-15 microg/kg/dose of intravenous (i.v.) anti-D (IgG)-coated RBCs per week (average of 300 microg/dose/week) for a median 3-month period (3-6 months). Treatment modality was evaluated on a weekly basis by platelet counts, measuring of hemoglobin levels, and performance of Coombs tests.


RESULTS
All patients presented a clinical response. Fifty-two patients (82.5%) increased their platelet count (PC) and 45 (69.8%) increased their PC >50 x 10(9)/L. In 34 cases, response was sustained. Six of nine nonsplenectomized patients (67%) increased PC, thus avoiding splenectomy; four patients attained a stable complete response (CR). Similar platelet responses were observed in homozygous and heterozygous Rh (D)-positive patients (Rh/Hr phenotypes). Currently, after >10 years, 43 patients present a now permanent complete response with platelet count >50 x 10(9)/L. Ten patients subsequently decreased their platelet count, although they were able to attain CR after receiving six doses of anti-D (IgG)-coated RBCs.


CONCLUSIONS
Based on our study of Fc receptor blockade treatment with anti-D (IgG)-coated RBCs with the most difficult cases of ITP, which resulted in a 69.8% successful response rate, we concluded that weekly prescription of anti-D (IgG)-coated RBCs is an effective approach to treating chronic refractory ITP.
Ambriz-Fernández
Raúl
R
Banco Central de Sangre, Centro Médico Nacional Siglo XXI (CMNSXXI), Instituto Mexicano del Seguro Social (IMSS), Mexico City, Mexico.
Martínez-Murillo
Carlos
C
Quintana-González
Sandra
S
Collazo-Jaloma
Juan
J
Bautista-Juárez
Javier
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D017707:Erythrocyte Transfusion; D004912:Erythrocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011696:Purpura, Thrombocytopenic / Q000097:blood / Q000276:immunology* / Q000628:therapy*; D011961:Receptors, Fc / Q000276:immunology*; D018029:Rho(D) Immune Globulin / Q000737:chemistry / Q000276:immunology*; D013154:Spleen / Q000502:physiology; D013997:Time Factors
D007074:Immunoglobulin G; D011961:Receptors, Fc; D018029:Rho(D) Immune Globulin