Immunologie et immunogénétique des affections rhumatologiques en zone tropicale

Rheumatoid arthritis in Burkina Faso: clinical and serological profiles

The objective of this work was to study the clinical and serological profiles of rheumatoid arthritis in Burkina Faso (West Africa). It is a cross-sectional study conducted from March 2006 to February 2009 in the Internal Medicine Department of the University Hospital Yalgado Ouedraogo. All patients seen in the rheumatologic consultation unit during this period, with rheumatoid arthritis fulfilling the ACR criteria, were routinely selected. The determination of anticyclic citrullinated peptide antibodies (ACPA) was carried out with a computerized method (Elia CCP, Phadia AB, Uppsala, Sweden). Values higher than 10 IU/l were considered positive. Forty-eight cases of rheumatoid arthritis (RA) were recruited throughout the study period among 2,194 (2.2 %) patients. Forty-two files were subjected to the study. There were 34 women and 8 men. The average age was 41.70 ± 13 years with extremes of 22 and 71 years. The average duration of the disease was 86.17 ± 82.01 months with extremes of 8 and 360 months. Rheumatoid factors (RF) were positive in 21 out of 30 patients (70.0%). The determination of ACPA carried out in all the patients was positive in 34 (81%) patients; their average value was 217 IU/l with extremes of 38 and 1,170. RF and ACPA were associated to bones erosions (p = 0.0001). Twenty-two patients were placed on methotrexate, eight on hydroxychloroquine, and three on salazopyrine. Nine were given only NSAIDs or prednisolone. No patients had had a biotherapy agent. The frequency of RA was low in our study compared to other African studies published so far. The particularity of RA cases reported in African series, including ours, is the rarity of extra-articular manifestations of the disease. The severity of the disease at presentation in the rheumatology clinic may be due to their late consultation among other causes.

High titers of autoantibodies in patients with sickle-cell disease

OBJECTIVE

Frequency and titers of autoantibodies in patients with sickle-cell disease (SCD) have been reported as relatively high. In a prospective study of 88 patients, we examined this "hyper-autoreactivity" and its clinical consequences.

METHODS

For 1 year, patients with SCD were screened for the presence in their serum of antinuclear, anti-double-stranded DNA, antiextractible nuclear antigens, anticardiolipin antibodies, and rheumatoid factors. A population of 85 sex-matched individuals of similar ethnic origin served as controls.

RESULTS

Whereas prevalence of autoantibodies did not differ between the 2 groups, the type and rate of antinuclear antibodies were different. Autoantibodies from the SCD patients showed various immunofluorescence patterns, whereas only speckled patterns at low titers were present in controls. No antibody specificity was found in either group. SCD patients and controls displayed similar rates of anticardiolipin antibodies, but the SCD patients tended to be more frequently positive for rheumatoid factors. Six-year followup of the SCD patients did not provide any clinical evidence for onset of an autoimmune disease, except for 1 patient who developed rheumatoid arthritis, with increasing antinuclear antibodies followed by emergence of specific markers 5 years later.

CONCLUSION

Patients with SCD displayed high titers of autoantibodies. This observation may be due only to immune activation and/or dysfunction in SCD, as neither pathogenic specificity of autoantibodies nor autoimmune clinical signs appeared in the majority of cases in our study.