s32_ab14

Analysis of the clinical profile, autoimmune phenomena and T cell subsets (CD4 and CD8) in Takayasu's arteritis: A hospital-based study

S.S. Uppal¹, S. Verma²

¹Department of Medicine, Faculty of Medicine, Kuwait University, Kuwait, and Rheumatology and Clinical Immunology Center and Laboratory, Command Hospital, Pune, India; ²Department of Biostatistics, National Institute of Virology, Pune, India.

ABSTRACT
Objective
To evaluate clinical and immunological abnormalities in patients with Takayasu's arteritis (TA) from India, with particular reference to autoimmune perturbations and abnormalities in T cell subsets (CD4 and CD8 cells).

Methods
16 consecutive patients with TA (11 females and 5 males) underwent clinical and laboratory evaluation inclusive of flow cytometric analysis of T cell subsets (CD4 and CD8). A control population of 94 age- and sex-matched blood donors was used to determine the normal T cell subsets. Student's t-test was used to compare the means.

Results
The mean age at onset was 23.4 + 2.3 yrs. Common symptoms observed were headache, limb claudication, abdominal pain and visual disturbance/blackout. Common clinical signs observed included reduced arterial pulsations, bruits, and a BP difference > 10 mm Hg in the upper limbs. Systemic hypertension was documented in 12 patients. The mean absolute lymphocyte count in the patients was 2289/ mm³. The mean CD4 count and CD4% were 1003 and 41 respectively; the mean CD8 count and CD8% were 755 and 34, respectively; and the mean CD4/8 ratio was 1.41. The patients had statistically significantly higher CD8 but not CD4 T cell values than controls. IgG and IgM immunoglobulin levels were increased. The mean multi-test CMI score in patients using CMI multi-test device of Pasteur Merieux was 14.6 mm. Two patients had an anergic response, 4 a partial response (1 - 13 mm), and 6 a full response of > 13 mm. Four patients hyper-responded with a score of > 20 mm. ANCA was positive in 2 patients. ANA was positive in 3 patients. IgG anticardiolipin was positive in 12 patients and IgM in 3; overall 12 patients were anticardiolipin positive by Elisa. Anti-b2GPI of the IgG variety was found to be positive in 3 patients and IgM in 2 patients; overall 3 patients being positive for the same. Nine of the patients with active disease were started on a combination of moderate dose prednisolone (20 - 40 mg once daily) along with weekly oral methotrexate (7.5 - 15.0 mg). Surgical intervention was required in 6 patients.

Conclusion
This study found an increase in CD8 positive T cell subsets, increased IgG and IgM immunoglobulin levels, and the presence of autoantibodies including ANA, ANCA, anticardiolipin and anti-b2GPI antibodies in TA patients. TA may be an autoimmune disorder with T cell aberrations. The relationship with antiphospholipid antibodies and anti-b2GPI needs to be explored and confirmed by other larger studies. The strikingly positive responses to tuberculin, as well as the multi-test CMI also indicate exaggerated T cell responses and cell mediated immunity in Takayasu's arteritis. Immunosuppressive therapy was successful in controlling disease activity in the majority, but surgery was needed for irreversible stenotic lesions.

Key words
Takayasu's arteritis, arteritis, Takayasu, CD4 lymphocyte count, CD8 lymphocyte count, flow cytometry, T cell subsets, clinical, immunology, aortoarteritis.

Please address correspondence to: Dr. S.S. Uppal, MD, FICP, Department of Medicine, Faculty of Medicine, Kuwait University, PO Box 24923, Safat 13110, Kuwait.
E-mail: uppalss@hsc.kuniv.edu.kw