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Bf and C4 phenotypes in patients with psoriasis
R J Wyatt1, C Wang, E C Hudson
1Department of Pediatrics, University of Tennessee, Memphis.
Insights
The C4*A6 allele, linked to a defective gene product, was significantly more common in Caucasian psoriasis patients compared to controls. Its role in psoriasis development remains unclear.
Area of Science:
- Immunogenetics
- Dermatology
Background:
- Complement proteins are crucial in immune responses.
- Genes for complement proteins Bf, C4A, and C4B are located in the major histocompatibility complex.
- Psoriasis is a chronic inflammatory skin condition with potential genetic links.
Purpose of the Study:
- To investigate the phenotype frequencies of complement proteins Bf, C4A, and C4B in Caucasian patients with psoriasis.
- To compare these frequencies with regional controls to identify potential genetic associations with psoriasis.
Main Methods:
- Phenotype frequencies of complement proteins Bf, C4A, and C4B were analyzed.
- A cohort of 49 Caucasian psoriasis patients from Memphis, Tennessee, was studied.
- Frequencies were compared against regional control data.
Main Results:
- No significant difference in Bf phenotype frequency was observed between psoriasis patients and controls.
- The C4*A6 allele was found in 26.6% of patients versus 5.4% of controls (p < 0.001, RR = 4.93).
- The C4*A6 allele is in linkage disequilibrium with the HLA B17 allele and associated with a functionally deficient gene product.
Conclusions:
- The C4*A6 allele shows a strong association with psoriasis in the studied Caucasian population.
- The specific role of the C4*A6 allele in the pathogenesis of psoriasis requires further investigation.
Abstract:
Phenotype frequencies for the complement proteins Bf (factor B), C4A and C4B were performed in a sample of 49 Caucasian patients with psoriasis followed in Memphis, Tennessee. The genes for these proteins are located in the major histocompatibility complex between the HLA-B and HLA-DR loci. Bf phenotype frequency did not differ significantly for the patients as compared to regional controls. The C4*A6 allele was present in 26.6% of the patients as compared to 5.4% of the controls, p less than 0.001, relative risk = 4.93. The C4*A6 allele is known to be in linkage disequilibrium with the HLA B17 allele and produces a functionally defective gene product. The role, if any, of C4*A6 in the pathogenesis of psoriasis is uncertain.