Polymorphism of the fourth component of complement in Turks

Area of Science:

• Immunogenetics
• Human Complement System

Background:

• Polymorphism in the fourth component of human complement (C4) is crucial for immune response.
• Understanding C4 allele frequencies in diverse populations aids in genetic and immunological studies.

Purpose of the Study:

• To analyze the polymorphism of the fourth component of human complement (C4) in a randomly selected Turkish population.
• To determine the frequencies of C4A and C4B alleles and haplotypes in Turks.
• To compare Turkish C4 genetic profiles with those of Caucasian and Asian populations.

Main Methods:

• EDTA-plasma samples from 142 unrelated Turks were analyzed.
• Neuraminidase and carboxypeptidase-B treated plasma underwent high-voltage agarose gel electrophoresis and immunofixation.
• C4B allotypes were further identified using Western blots with a specific monoclonal antibody.

Main Results:

• The C4B*5 allele, common in Asian populations, was not detected.
• The C4A*3-C4B*1 haplotype was the most frequent (28%) but less common than in Caucasians.
• C4A and/or C4B null allotypes were observed in 34.6% of subjects, with C4B null being the most frequent (26%).

Conclusions:

• The genetic profile of the Turkish population for C4 polymorphism shows a mix of European and Asian characteristics.
• The observed C4 null allotype frequencies warrant further investigation.
• This study contributes to understanding the genetic diversity of the human complement system in different ethnic groups.