The prozone effect exerted by the complement-binding anti-Le^a on anti-D

Prozone phenomenon is seen with very high-titer antibodies in an immune serum.

The prozone effect on anti-D by a low-titer anti-Le^a was investigated associated with neonatal jaundice.

Standard methods were used in investigations.

The child was born at full-term developed mild jaundice. With weak direct antiglobulin test+, her indirect serum bilirubin was progressed to 27.5 mg/dL in 48 h. Anti-D and anti-Le^a were detected in the mother. Both these antibodies were detected in the child's serum though the eluate from red blood cells (RBCs) contained only anti-D. Mother's anti-D was masked by anti-Le^a if the RBCs possessed both the antigens together. Anti-D was revealed only with D-positive RBCs lacking Le^a or if the serum was modified by mixing with Le^a+ saliva or was heated at 56°C or fortified with citrate solution.

An anti-D showed prozone effect exerted by the complement-fixing anti-Le^a in the test.