Association of Haptoglobin Heterozygosity (HP1-2) with the Risk of COVID-19 Infection in a Sample of the Iranian Population.

Background: COVID-19 is a highly contagious viral disease that primarily affects the respiratory system and occasionally the gastrointestinal system, and it was declared a pandemic in 2020. Haptoglobin is an acute-phase protein and a potent antioxidant in the body, which exerts its antioxidant effect by binding to free hemoglobin. Haptoglobin has three main variants (Hp1-1, Hp1-2, Hp2-2), each with different antioxidant capacities. The purpose of this study is to investigate frequency of the haptoglobin variants in COVID-19 patients compared to a control group.

Methods: This study was conducted on 148 COVID-19 patients and 145 healthy individuals from the Sistan and Baluchestan province. DNA was isolated from whole blood using the salt precipitation method, and the determination of haptoglobin genotypes (Hp1-1, Hp1-2, and Hp2-2) was performed using Conventional PCR.

Results: This study analyzed haptoglobin (HP) genotypes in COVID-19 patients and controls, finding no significant difference in HP variant frequencies between groups (p= 0.529). However, the HP1-2 genotype was associated with a twofold increased COVID-19 risk in men (OR=2.069, p= 0.021), and the HP1 allele significantly raised infection risk (OR= 1.62, p= 0.039). Hospitalizations and respiratory symptoms were significantly higher in COVID-19 patients (p= 0.0001 and p= 0.0176, respectively).

Conclusions: These results suggest that haptoglobin variants are not risk factors for COVID-19 infection in the overall population (both males and females). However, men with the HP1-2 genotype are 1.9 times more likely to develop COVID-19 infection compared to men with HP1-1 and HP 2-2 genotypes.