FY Antibody
Description
Definition and Classification of FY Antibodies
FY antibodies represent immunoglobulins directed against antigens in the Duffy blood group system, which includes Fy a, Fy b, and Fy3. These antibodies are critical in transfusion medicine and malaria resistance. The Duffy system is defined by two main alleles: FY*A (coding for Fy a) and FY*B (coding for Fy b), with additional variants like FY*O (Fy(a-b-)) and FY*X (weak Fy b expression) .
Key Antibodies in the Duffy System
| Antibody | Target Antigen | Reactivity | Clinical Implications |
|---|---|---|---|
| Anti-Fy a | Fy a (FY*A allele) | IgG, reacts with Fy a+ RBCs | Hemolytic transfusion reactions, HDN |
| Anti-Fy b | Fy b (FY*B allele) | IgG, reacts with Fy b+ RBCs | Rare, milder reactions |
| Anti-Fy3 | All Fy+ RBCs (except Fy(a-b-)) | IgG, pan-reactive | Delayed hemolytic transfusion reactions |
Genetic Basis and Antigen Expression
The Duffy gene (FY, ACKR1) on chromosome 1 encodes a glycoprotein receptor for chemokines (e.g., CXCL8, CCL5) and serves as a receptor for Plasmodium vivax .
Genetic Polymorphisms
-
FYA/FYB: Codominant alleles differing at position 42 (Gly/Asp) .
-
FY*O: A promoter mutation (T→C at -33) silencing erythroid expression, leading to Fy(a-b-) .
Phenotype Distribution
| Phenotype | Fy a | Fy b | Prevalence |
|---|---|---|---|
| Fy(a+b+) | + | + | 50% Caucasians |
| Fy(a+b-) | + | - | 10% Caucasians, 30% Asians |
| Fy(a-b+) | - | + | 20% Caucasians, 70% Africans |
| Fy(a-b-) | - | - | 68% Sub-Saharan Africans |
Clinical Significance in Transfusion Medicine
FY antibodies are immune (IgG) and typically acquired via transfusion or pregnancy. They cause mild-to-severe hemolytic reactions .
Transfusion Guidelines
| Antibody | Compatible Blood | Testing Phase |
|---|---|---|
| Anti-Fy a | Fy a- (Fy(a+b-), Fy(a-b-)) | AHG |
| Anti-Fy b | Fy b- (Fy(a+b-), Fy(a-b-)) | AHG |
| Anti-Fy3 | Fy(a-b-) | AHG |
Hemolytic Disease of the Newborn (HDN)
Role in Malaria Resistance
The Fy a antigen reduces P. vivax invasion by 40–50% compared to Fy b, conferring selective advantage in endemic regions .
Malaria Resistance Data
| Phenotype | P. vivax Risk | Mechanism |
|---|---|---|
| Fy(a+b-) | 30–80% reduced | Lower PvDBP binding |
| Fy(a-b+) | High susceptibility | Strong PvDBP interaction |
| Fy(a-b-) | No resistance | No receptor |
Research Findings and Data Tables
Chemokine Binding Specificity
| Chemokine | Role | Duffy Interaction |
|---|---|---|
| CXCL8 (IL-8) | Neutrophil recruitment | High-affinity binding |
| CCL5 (RANTES) | T-cell activation | Moderate binding |
| CXCL4 (PF-4) | Platelet activation | Critical for P. falciparum killing |
Renal Transplant Outcomes
| Donor/Recipient | Duffy Mismatch | Risk |
|---|---|---|
| Fy+ donor → Fy- recipient | Anti-Fy a/b | Acute rejection |
| Fy- donor → Fy+ recipient | No antibodies | Safe |
Product Specs
**Constituents:** 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- The PPLPP domains of FY were found to be non-essential for the abscisic acid-influenced repression of germination. PMID: 22282534
- The expression domain of FY aligns with its roles in essential and flowering-time functions. FY may mediate both regulated and constitutive RNA 3'-end processing. PMID: 16033802
- The interaction between FCA and FY influences alterations in FCA transcript processing. PMID: 16940039
