Frequency analysis of B lymphocytes specific for Rh antigens in naturally immunized Rh-negative women.
OBJECTIVE
Despite a successful outcome of the anti-D prophylaxis programme, alloimmunization still occurs. The aim of this study was to estimate the frequency of Rh-specific B lymphocytes in the peripheral blood of nine Rh-alloimmunized individuals at different time intervals after parturition.


METHODS
The donors' B lymphocytes were transformed with Epstein-Barr virus (EBV) and cultured at different cell densities over a feeder of human fetal fibroblasts. Culture supernatants were screened for human immunoglobulin by enzyme-linked immunosorbent assay (ELISA) and for anti-Rh antibody by using a direct haemagglutination technique. The percentage of CD19+ B lymphocytes in peripheral blood was determined by flow cytometry, and the frequency of Rh-specific B lymphocytes was estimated by limiting-dilution assay (LDA).


RESULTS
The frequency of Rh-specific B lymphocytes varied from 1 : 150 to 1 : 27,850 in different donors. There was a decrease in this frequency and level of anti-Rh antibody with increase in time interval between bleeding and last exposure to the antigen. Furthermore, a positive correlation was observed between the titre of Rh-specific antibody and frequency of Rh-specific B cells in each of three subjects bled at multiple time-points postdelivery.


CONCLUSIONS
The magnitude of the specific antibody response to Rh antigens varies greatly in Rh-alloimmunized women, which partly reflects the difference in frequency of specific B cells in these individuals.
National Cell Bank of Iran, Pasteur Institute of Iran, Tehran.
R P K
RP
Pasha
M A
MA
Shokrgozar
Z S
ZS
Bahrami
F
F
Shokri
D000328:Adult; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000276:immunology*; D018929:Cell Culture Techniques / Q000379:methods; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000097:blood; D015994:Incidence; D007519:Isoantigens; D011247:Pregnancy; D012203:Rh Isoimmunization / Q000276:immunology*; D012204:Rh-Hr Blood-Group System / Q000097:blood / Q000276:immunology*
D007136:Immunoglobulins; D007519:Isoantigens; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen