Haptoglobin Phenotype, Serum Iron Levels and Severity in Multi-Drug Resistant Mycobacterium Tuberculosis Patients in Ibadan

Haptoglobin (Hp) phenotypes possess biochemical and functional efficiencies accounting for distinct antioxidant and immuno-modulatory capacities. Hp 2.2 phenotype has been observed as a genetic risk factor for several infectious diseases, including Mycobacterium tuberculosis (MTB). Nigeria is ranked 4th globally, with 590,000 cases, the increase in antibiotic resistance worldwide, has called for better personalized treatment on a genetic level, as patients with multi-drug-resistant tuberculosis (MDR-TB) need to undergo extended, expensive, and hazardous second-line therapy. Given that iron homeostasis is crucial for the microbiological growth of MTB, the objective of this work was to observe the relationship and investigate possible associations with the Hp phenotypes as well as CRP concentrations measuring severity in TB patients. Fifty (50) clinically and Laboratory diagnosed tuberculosis patients were classified by the Gene-Xpert system into MDR-TB (25) and DS-TB (25) and 25 health control were recruited for the study after ethical clearance. Haptoglobin phenotypes were determined using electrophoresis while plasma iron and CRP levels were determined through spectrophotometry using kits obtainable from My BioSource Inc. The Haptoglobin phenotype distribution (Hp 1.1, Hp 2.1, and Hp 2.2) showed the following: MDR-TB population, 5(20%), 7 (28%), and 13 (52%). Overall, MDR-TB represents a severe spectrum of the disease compared to control due to increased levels of inflammation and increased serum iron, influenced by haptoglobin 2-2 phenotype. Hp 2-2 positively correlated with increased Fe and CRP levels (0.014) and (p=0.009) respectively but not with Hp 1-1 and Hp 2-2 phenotypes. The Hp 2.2 phenotype prevalence in the MDR-TB population can be used as a predictive/predisposing factor to determine the trend for individuals who contract TB. The Hp 2-2 gene polymorph is almost exclusive to the African race explaining the high cases of TB. It is therefore important to know all risk factors, especially on a genetic level, to better understand and manage the disease.