Undifferentiated Spondyloarthropathies in Brazilians: Importance of HLA-B27 and the B7-CREG Alleles in Characterization and Disease Progression

PERCIVAL D. SAMPAIO-BARROS, ROSENEIDE A. CONDE, EDUARDO A. DONADI, MARIA HELENA S. KRAEMER, LIGIA PERSOLI, IBSEN B. COIMBRA, LILIAN TERESA L. COSTALLAT, ADIL M. SAMARA, and MANOEL B. BÉRTOLO

ABSTRACT.

Objective. To analyze the profile of the HLA-B27 and B7 cross-reactive group (CREG) alleles and the role of these markers in disease characterization and progression in patients with undifferentiated spondyloarthropathies (uSpA).

Methods. A total of 80 patients with a diagnosis of uSpA (40 HLA-B27 positive and 40 HLA-B27 negative) were prospectively studied for 2 years. The control group consisted of 66 HLA-B27 positive and 112 HLA-B27 negative individuals without a history of seronegative SpA. HLA-B alleles were typed at low (B7-CREG alleles, i.e., B*7, B*54, B*55, B*56, B*40, B*42) or high resolution (B*27 alleles) using polymerase chain reaction-amplified DNA hybridized with sequence-specific oligonucleotide probes.

Results. HLA-B*2705 was the most frequent allele, observed in 92.5% of the patients and in 77% of the controls, followed by the HLA-B*2702, observed in 5% of the patients and in 12% of the controls. HLA-B*2704 was observed in only one patient (2.5%), and was absent in the control population. HLA-B*2703 (6%) and HLA-B*2707 (5%) alleles were observed only in controls. No associations between HLA-B*27 alleles or B7-CREG alleles and any specific manifestation of uSpA were observed. HLA-B27 positive patients more frequently presented juvenile onset SpA (p = 0.002) and progression to ankylosing spondylitis (AS) (p = 0.03) than did HLA-B27 negative patients. The B7-CREG alleles were observed in 5% of the HLA-B27 positive uSpA group, in 25% of the HLA-B27 negative uSpA group, in 7% of the HLA-B27 positive controls, and in 13% of the HLA-B27 negative controls; a significant association was observed between the presence of the B7-CREG and the HLA-B27 negative uSpA group (p = 0.012).

Conclusion. The frequency of the HLA-B*2705 allele among the B27 positive uSpA patients of this series was closely similar to that reported for patients with ankylosing spondylitis (AS). The presence of HLA-B*27 alleles was associated with the progression to AS, and the presence of B7-CREG was associated with uSpA in the HLA-B27 negative group. (J Rheumatol 2003;30:2632–7)

Key Indexing Terms:

FOLLOWUP
HLA-B27
ALLELES
SPONDYLOARTHROPATHIES
UNDIFFERENTIATED SPONDYLOARTHROPATHIES

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From the Rheumatology Unit, Department of Internal Medicine, State University of Campinas, Faculty of Medical Sciences, Campinas, Brazil.

Supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).

P.D. Sampaio-Barros, MD, PhD, Assistant Rheumatologist; R.A. Conde, Biologist, Laboratory of Rheumatology; E.A. Donadi, MD, PhD, Associate Professor, Immunology Unit, State University of São Paulo at Ribeirão Preto; M.H.S. Kraemer, PhD, Assistant Professor, Department of Clinical Pathology; L. Persoli, PhD, Assistant Professor, Haematology Unit; I.B. Coimbra, MD, PhD, Assistant Professor, Rheumatology Unit; L.T.L. Costallat, MD, PhD, Professor of Rheumatology; A.M. Samara, MD, PhD, Professor of Rheumatology and Chief, Rheumatology Unit; M.B. Bértolo, MD, PhD, Assistant Professor, Rheumatology Unit, Faculty of Medical Sciences, State University of Campinas.

Address reprint requests to Dr. P.D. Sampaio-Barros, Disciplina de Reumatologia, Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadua de Campinas (UNICAMP), Barao Geraldo, Campinas SP, Brazil, CEP 13081-970. E-mail: psbarros@fcm.unicamp.br

Submitted October 15, 2002; revision accepted May 21, 2003.

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