Anti‐Sc1 in pregnancy

Abstract

Anti-Sc1 was detected in a gravida-2 patient at 12 weeks' gestation. At 29 weeks, the antibody was found to be of the IgG3 subclass with a titer of 16, score 36, by the indirect antiglobulin test, and it produced 7 percent lysis by antibody-dependent cellular cytotoxicity (ADCC) assay, a finding that suggested an unaffected fetus. The titer remained constant throughout the pregnancy, as did the IgG subclass and activity in the ADCC assay. At delivery of the full-term infant, the cord hemoglobin was 13.5 g per dL and the direct antiglobulin test was positive (3+) with anti-IgG. The infant did not require transfusion. A sample taken 9 weeks after delivery showed 44 percent lysis in the ADCC assay. The anti-Sc1 titer was 32, score 65.

Review: the Scianna blood group system

“…Another example of anti-Sc1 was described by Kaye et al 21 In this case report, anti-Sc1 associated with pregnancy was reported in a 28-year-old gravida-2 woman of Indian extraction. The anti-Sc1 was determined to be solely of the IgG3 subclass.…”

Scianna Blood Group System

“…Testing of 269 000 South London blood donors with anti -SC1 revealed one SC: -1 individual [19] , suggesting the following gene frequencies: SC * 01 0.9981; SC * 02 0.0019. No SC: -1 person was found as a result of testing red cells from 1600 North Americans [14,18] and 29 737 Welsh donors [20] .…”

The first case of severe acute hemolytic transfusion reaction caused by anti‐Sc2

“…Alloanti‐Sc1 and ‐Sc2 are dominantly of the immunoglobulin (Ig)G antibody class, react best by antiglobulin test, and do not fix complement . While few cases of hemolytic disease of the fetus and newborn (HDFN) have been ascribed to anti‐Sc1 and anti‐Sc2, neither has previously been associated with hemolytic transfusion reactions (HTRs). There is, however, one report of mild delayed HTR associated with anti‐Sc7 .…”