1. non- Lofgren's Patients
ASSOCIATIONS OF HLA-DRB1 GENOTYPE WITH CLINICAL EXPRESSION OF SARCOIDOSIS IN PORTUGUESE PATIENTS
Sofia Neves1, Dina Lopes2, António Morais3, Cláudia Carvalho2, Andreia Bettencourt2, Barbara Leal2, Patrícia Mota3, Mª Brito1, Sílvia Torres1, Sandra Maia2,
Paulo P Costa1,4, Berta M Silva1
1. Centro Hospitalar de Vila Nova de Gaia e Espinho (CHVNGE) – Vila Nova de Gaia, Portugal
2. Laboratório de Imunogenética, UMIB – ICBAS-UP, Porto
3. Hospital de São João (HSJ) – Porto, Portugal
4. Instituto Nacional Dr. Ricardo Jorge (INSA) – Porto, Portugal
Introduction
Sarcoidosis is a granulomatous multisystem disorder of unclear etiology that affects the lungs (90%), heart, skin and central nervous system. Strong genetic predisposition have been claimed and several studies conducted in different populations have reported association between sarcoidosis and HLA (Human Leucocyte Antigen) class I and class II alleles. In Swedish patients an association between HLA-DRB1*15 allele and a chronic course of sarcoidosis was observed. HLA-DRB1*01 and HLA-DRB1*04 alleles were correlated with protection against disease in the same cohort. It has also been described that the HLA-DRB1*03 allele is associated with Lofgren’s Syndrome (LS), a distinct form of sarcoidosis. This syndrome is characterized by an acute onset with bilateral hilar lymphadenopaty, erythema nodosum (EN), ankle arthritis and in has general a favorable prognosis. The reason why HLA class II is associate with sarcoidosis is not clear, but is likely due to their pivotal role for mounting T cells specific immune responses, which in sarcoidosis results in lung accumulation and activation of CD4+ T cells, granuloma formation and in eventually chronic inflammation and fibrosis.
Aim: To investigate the putative association of HLA-DRB1 with the clinical expression of sarcoidosis in portuguese patients.
Patients and Methods
A total of 106 patients (42 male, 64 Female; mean age of, 50.8 years) followed in Centro Hospitalar de Vila Nova de Gaia e Espinho (CHVNGE) and Hospital São João (HSJ) with sarcoidosis and 282 control group, were studied. Twenty of these patients were classified as Lofgren’s Syndrome and 86 as non Lofgren Syndrome.
Patients and controls groups are from homogenous of European descendent from north of Portugal. Samples were genotyped for HLA-DRB1 using PCR-SSP (Polymerase Chain Reaction- Sequence Specific Primers). Differences in frequencies were evaluated using the Chi-Square test and Fisher’s exact test. Analyses were done with SPSS v.20 software and significant levels were set at α<0.05.
Results δ
Table 1: HLA-DRB1 genotype frequencies in control group and in sarcoidosis patients.
Table 2: HLA-DRB1 genotype frequencies in Lofgren patients and in non-Lofgren patients
δ- p= 0,046 OR= 0,162;
CI= 0,021-1,236 Δ
Lofgren's Patients
(n=20)
non- Lofgren's Patients
(n=86) OR
95% CI p
DRB1 n %
*01 5 25 6 7
0,225
0,061-0,833
0,017
*03 35 17 20 - ns
*04 1 23
*07 2 10 22 26
*08 8
*09 4
*10
*11 18 21
*12
*13 9 45 27
*14 3
*15
*16
Δ- p= 0,025; OR= 2.913;
CI= 1,100-7,710
Control group
(n=282)
All Patients (n=106) OR
95% CI P
DRB1 n %
*01 66 23 11 10
0,379
0,192-0,750
0,004
*03 44 16 24 - ns
*04 69 21 20
*07 72 26
*08 9 8
*09 14 5 4
*10 2
*11 55 22
*12 3 7
*13 84 30 32
*14 17 6
*15 56
*16 13
Graphic 1: HLA-DRB1 comparison with control group and Lofgren patients
The comparison between LS and the control group show that the frequency of HLA-DRB1*03 allele was significantly increased in these patients (35% vs 16%, OR=2.913, CI= , p=0.025) and the HLA-DRB1*04 allele (5% vs 24%, OR=0,162, CI=0,021-1,236, p=0,046) was decrease in the same group (graphic 1).
ns- non significance
ns- non significance
The distribution of the HLA-DRB1 genotype frequency in LS and non-LS patients was significantly decreased when compared with LS patients (table 2).
The frequency of HLA-DRB1*01 allele was significantly decreased in sarcoidosis patients compared with control group (table 1).
Discussion
Numerous studies suggest that there is a strong association between HLA alleles and Sarcoidosis. We report for the first time an association between HLA-DRB1*01 allele and Lofgren’s Syndrome (LS). We also confirmed the already described protective role of this allele with Sarcoidosis. This allele has also been shown to protected against Multiple Sclerosis, another immune mediated inflammatory disorders and has been also correlated with a less severe form in patients with Rheumatoid Arthritis. In agreement with previous reports we observed in our population the association of HLA-DRB1*03 allele with LS. Despite the known HLA-DRB1*04 association with Sarcoidosis, this study only confirmed these data for LS patients, probably due to the small sample size.
This study reveals the importance of sub-grouping Sarcoidosis patients when calculating genetic risk factors. On the basis of the results obtained in this study we are convinced that HLA typing can be a useful tool in predicting the clinical expression of Sarcoidosis. Specific HLA associations may have obvious clinical implications in the patients follow-up and treatment.
References .
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3. Morais A, Alves H, et al; HLA class I and II and TNF- gene polymorphisms in sarcoidosis patients; 2008
4. A. Wennerstrom, A. Pietinalho, et al; HLA-DRB1 allele frequencies and c4 copy number variation in finnish sarcoidosis patients and associations with disease prognosis; 2011