the b cell function of a patient with low serum immunoglobulin ( ig ) levels and with an interstitial deletion in the short arm of one of her x chromosomes ( del ( xp ] and the b cell function of her relatives were analyzed by indirect protein a plaque-forming cell ( pfc ) assay and by measuring immunoglobulin secretion in vitro by elisa .
C1520168
xp
C0007634
cell