Detection of STAT4 in Multiple Sclerosis patients by polymerase chain reaction and flowcytometry

Multiple sclerosis (MS) is a disease of the central nervous system, characterized by progressive demyelination and inflammation. MS is characterized by immune system attacks on the myelin sheath surrounding nerve fibers. Genome-wide association studies revealed a polymorphism in the signal transducer and activator of transcription 4 (STAT4) gene that increases risk for MS. This polymorphism affects the T helper1 (Th1) cells to secrete the cytokine interferon-gamma when stimulated by interleukin (IL)-12. This study aimed to determine the association of MS active disease with STAT4 genotypes, detected by the polymerase chain reaction (PCR) and STAT4 protein level detected by flowcytometry. The study included 80 MS patients, and 70 controls matched for age and gender. We used the restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) and flowcytometry to detect STAT4 gene polymorphism. Our results showed that, in MS patients, STAT4 genotypes of GC and CC as detected by PCR, were more common when compared to controls. The C allele of the STAT4 gene was also more common in MS patients than controls. The STAT4 GC genotype was associated with MS disease activity. Active MS patients also had a much greater frequency of the STAT4 C allele than the G allele or the control group. The STAT4 proteins level by flowcytometry among the active MS studied patients was higher than its level in the inactive patients and controls. In conclusion, this study demonstrated that both techniques are complementary to each other to detect STAT4 level in MS patients and its association with the disease activity. STAT4 proteins expression detected by flowcytometry in the peripheral blood leukocytes could be used as a biomarker for monitoring disease activity in MS patients.