Nonimmune chronic idiopathic neutropenia of adults (NI-CINA) is a frequently seen granulocytic disorder characterized by the “unexplained” persistent decrease of the number of circulating neutrophils below the lower limit of the normal distribution in a given ethnic population.1,2 The diagnostic criteria allowing the identification of the condition among other types of chronic neutropenia are presented elsewhere.3-5 The cause of the disorder and the underlying mechanisms leading to neutropenia in the affected subjects are unknown, but recent studies in our laboratory provided strong evidence for the existence of an unrecognized low-grade chronic inflammatory process in these patients, which may be involved in the pathogenesis of NI-CINA by increasing the production of a variety of proinflammatory cytokines and chemokines3 and therefore affecting both neutrophil production in bone marrow4 and neutrophil extravasation in the periphery.5 Here, we describe a predisposition of HLA-DRB1*1302 haplotype–carrying individuals to develop NI-CINA.

The study was carried out on 56 NI-CINA patients and 39 healthy volunteers, all residents of the island of Crete. Venous blood was collected into vacutainer tubes containing ethylenediaminetetraacetic acid (EDTA) as anticoagulant and used as a DNA source. DNA extraction was carried out by salting-out technique. For the typing of HLA alleles, polymerase chain reaction (PCR) was utilized. HLA-A, -B, and -C alleles were typed using PCR-sequence specific primers (PCR-SSP) with primer sets provided by PelFreez Clinical systems (Brown Deer, WI). HLA-DRB1 alleles were typed using the ELPHA high resolution hybridization system provided by Biotest AG (Dreieich, Germany). HLA-DQB1 and DPB1 alleles were typed using the InnoLiPa reverse slot blot hybridization system provided by Murex (Immunogenetics, Zwijndzecht, Belgium). Results were analyzed with the Yates continuity-corrected chi-square test using the GraphPad program.

We found that the frequency of the HLA-DRB1*1302 haplotype was 21.43% in the group of patients compared to 2.56% in the controls (P = .0199) (Table 1). The relative risk for the carriers was 8.36. The frequencies of all other HLA haplotypes did not differ significantly between patients and control subjects.

Table 1.

Frequency of selected HLA-DRB1 haplotypes in the NI-CINA patients

HaplotypePatients (%) (n = 56)Healthy controls (%) (n = 39)χ2-valuePvalue
HLA-DRB1*0101 4  (7.14) 2  (5.13) 0.9748 ns  
HLA-DRB1*0301 3  (5.36) 1  (2.56) 0.8827 ns  
HLA-DRB1*0701 12  (21.43) 6  (15.38) 0.6359 ns  
HLA-DRB1*1001 2  (3.57) 3  (7.69) 0.6761 ns  
HLA-DRB1*1101 10  (17.86) 12  (30.77) 0.2223 ns  
HLA-DRB1*1104 21  (37.5) 15  (38.46) 0.9045 ns  
HLA-DRB1*1201 2  (3.57) 2  (5.13) 0.8827 ns  
HLA-DRB1*1301 3  (5.36) 5  (12.82) 0.3612 ns  
HLA-DRB1*1302 12  (21.43) 1  (2.56) 5.4210 P = .0199  
HLA-DRB1*1401 5  (8.93) 6  (15.38) 0.5212 ns  
HLA-DRB1*1501 3  (5.36) 4  (10.26) 0.6171 ns  
HLA-DRB1*1502 4  (7.14) 3  (7.69) 0.7655 ns  
HLA-DRB1*1601 10  (17.86) 3  (7.69) 0.2650 ns 
HaplotypePatients (%) (n = 56)Healthy controls (%) (n = 39)χ2-valuePvalue
HLA-DRB1*0101 4  (7.14) 2  (5.13) 0.9748 ns  
HLA-DRB1*0301 3  (5.36) 1  (2.56) 0.8827 ns  
HLA-DRB1*0701 12  (21.43) 6  (15.38) 0.6359 ns  
HLA-DRB1*1001 2  (3.57) 3  (7.69) 0.6761 ns  
HLA-DRB1*1101 10  (17.86) 12  (30.77) 0.2223 ns  
HLA-DRB1*1104 21  (37.5) 15  (38.46) 0.9045 ns  
HLA-DRB1*1201 2  (3.57) 2  (5.13) 0.8827 ns  
HLA-DRB1*1301 3  (5.36) 5  (12.82) 0.3612 ns  
HLA-DRB1*1302 12  (21.43) 1  (2.56) 5.4210 P = .0199  
HLA-DRB1*1401 5  (8.93) 6  (15.38) 0.5212 ns  
HLA-DRB1*1501 3  (5.36) 4  (10.26) 0.6171 ns  
HLA-DRB1*1502 4  (7.14) 3  (7.69) 0.7655 ns  
HLA-DRB1*1601 10  (17.86) 3  (7.69) 0.2650 ns 

Yates continuity-corrected chi-square test. Statistically significant at P ≤ .05. ns, nonsignificant difference.

Proportions of haplotype-carrying subjects are in parentheses.

The clinical and biologic significance of our finding is unknown, but it seems possible that the frequency of the HLA-DRB1*1302 haplotype may have a role in the development of the aforementioned unrecognized low-grade chronic inflammation. Associations of HLA haplotypes with chronic inflammatory processes have already been well documented in a variety of clinical disorders.8 We believe that the increased frequency of the HLA-DRB1*1302 haplotype in NI-CINA patients may indicate the possible genetic basis in the development of such an inflammation, and thus it may predispose the haplotype-carrying subjects to develop the disorder.

1
Dale
DC
Guerry
D
Wewerka
J
Bull
J
Chusid
M
Chronic neutropenia.
Medicine (Baltimore)
58
1979
128
144
2
Papadaki
HA
Xylouri
I
Coulocheri
S
Kalmanti
M
Kafatos
A
Eliopoulos
GD
Prevalence of chronic idiopathic neutropenia of adults among an apparently healthy population living on the island of Crete.
Ann Hematol.
78
1999
293
297
3
Papadaki
HA
Coulocheri
SA
Eliopoulos
GD
Patients with chronic idiopathic neutropenia of adults have increased serum concentrations of inflammatory cytokines and chemokines.
Am J Hematol.
65
2000
271
277
4
Papadaki
HA
Giouremou
K
Eliopoulos
GD
Low frequency of myeloid progenitor cells in chronic idiopathic neutropenia of adults may be related to increased production of TGF-β1 by bone marrow stromal cells.
Eur J Haematol.
63
1999
154
162
5
Papadaki
HA
Eliopoulos
GD
Enhanced neutrophil extravasation may be a contributing factor in the determination of neutropenia in patients with chronic idiopathic neutropenia of adults.
Eur J Haematol.
61
1998
272
277
6
Tongs
S
March
SGE
Bunce
M
et al
HLA class I DNA typing study
D. Charron, ed. Genetic Diversity of HLA, Functional and Medical Implications.
1997
119
215
EDK Medical and Scientific International Publishers
Paris
7
Saiki
RK
Walsh Levenson
CH
Erlich
HA
Genetic analysis of amplified DNA with immobilized sequence-specific oligonucleotide probes.
Proc Natl Acad Sci U S A.
86
1989
6230
6234
8
Brostoff
J
Scadding
GK
Male
D
Roit
IM
Clinical Immunology.
1994
2.1
2.14
Mosby
London
Sign in via your Institution