The phenotype and genotype of rheumatoid arthritis in the Democratic Republic of Congo
Arthritis Research & Therapy 2013, 15:R89 doi:10.1186/ar4269Published: 19 August 2013
The aim of this study was to describe the phenotype and genotype of rheumatoid arthritis (RA) in Congolese patients.
All consecutive RA patients attending Kinshasa University Hospital in a three year time period were included. Demographics, clinical features and tobacco consumption were noted. Disease activity score 28 based on the erythrocyte sedimentation rate (DAS-28-ESR), health sssessment questionnaire (HAQ), anti-cyclic citrullinated peptide (anti-CCP) antibodies and rheumatoid factor (RF) were determined. Radiographs were scored according to Sharp-van der Heijde. On a subset of patients and controls human leukocyte antigen (HLA)-DRB1 typing was performed.
114 females and 14 males aged 51.2 +/- 14.9 were included. Mean duration of symptoms was 4 years. Moderate tobacco consumption was reported in a minority of patients. DAS-28 at first visit was > 5.1 and HAQ[greater than or equal to] 0.5 in all patients. X-rays showed joint erosion and/or joint space narrowing, mostly of a moderate grade in 55.8%. Anti-CCP and/or RF were present in 48.6% of patients with available data (n=72) and in 3.0% of controls (n=67). Radiographic changes and nodules were more frequent in RF or anti-CCP positive patients. One copy of the shared epitope was found in 13 patients (35.1%) and 3 controls (12.5%). Two copies were found in one patient (2.7%) and in one control (4.2%).
Congolese patients with RA consult long after disease onset. Despite this delay the majority presents without major damage and are RF, anti-CCP and SE negative. We put forward the hypothesis that besides different environmental factors there is probably also a particular genetic risk profile in Congolese patients, different from the HLA-DRB1 shared epitope.