Mannose binding lectin 2 promotor-221 X/Y gene polymorphism in Egyptian systemic lupus erythematosus patients

Abstract Aim of the work The present study was undertaken to determine whether mannose binding lectin-2 (MBL2) promotor-221X/Y gene polymorphism had a possible association with systemic lupus erythematosus (SLE) in Mansoura city. Patients and methods We analyzed functional polymorphisms in the promoter of MBL2 gene in 106 Egyptian SLE patients and 99 healthy controls by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). SLE disease activity was evaluated using SLE Disease Activity Index (SLEDAI) and organ damage was evaluated using SLE International Collaborating Clinic Damage Index (SLICC/DI). Results The patients were 95 females and 11 males with a mean age of 34.4 ± 10.2 years and disease duration of 4 ± 3.03 years. Genotype frequencies of MBL2 were significantly different between patients and controls. The YY genotype was significantly associated with SLE in 77 (72.6%) patients compared to the control in 59 (59.6%) ( p  = 0.048). The XY genotype was in 29 (27.4%) patients and in 40 (40.4%) control. An association was found between the XY genotype and alopecia ( p  = 0.048), central nervous system involvement ( p  = 0.03), vasculitis ( p  = 0.004) and anti-phospholipid syndrome ( p  = 0.001) while the YY genotype was associated with discoid rash, low serum complement level (C3; p  = 0.014 and C4; p  = 0.008) and with the presence of anticardiolipin antibodies ( p  = 0.032). MBL genotype did not show any correlation with SLEDAI or SLICC/DI. Conclusion Our results indicate that MBL2 promotor-221X/Y polymorphism is a possible key-player for SLE development as well as the occurrence of some clinical and laboratory features. Further longitudinal studies including other single nucleoproteins are needed to clarify the role of MBL2.