Year : 2008  |  Volume : 50  |  Issue : 3  |  Page : 166--170

Analysis of the role of human leukocyte antigen class-I genes to understand the etiopathology of schizophrenia


Bisu Singh1, Sikta Banerjee1, Nirmal K Bera2, Chitta R Nayak3, Tapas K Chaudhuri1,  
1 Department of Zoology, Cellular Immunology Laboratory, University of North Bengal, Siliguri 734 430, India
2 Department of Psychiatry, North Bengal Medical College and Hospital, Siliguri, India
3 Computer Centre, University of North Bengal, Siliguri - 734 430, West Bengal, India

Correspondence Address:
Tapas K Chaudhuri
Cellular Immunology Laboratory, Department of Zoology, University of North Bengal, Rajarammohanpur, Siliguri -734 013, West Bengal
India

Abstract

Background: Schizophrenia is the paradigmatic illness of psychiatry. The involvement of immunological and immunopathological mechanisms in the etiopathogenesis of schizophrenia has been a matter of research, with recently increasing effort. Aims: In this study, we investigated the incidence of human leukocyte antigen (HLA) Class I antigens to understand the role of HLA genes in schizophrenia. Materials and Methods: India born schizophrenic patients in and around Siliguri who attended outpatient department (OPD) of Department of Psychiatry, North Bengal Medical College and Hospital were considered for the present study. After the longitudinal follow up, 50 patients were enrolled for the study. The same number of age, sex and ethnically matched healthy subjects were considered as control. Low resolution polymerase chain reaction-sequence specific primer method was applied for typing the HLA antigens. Statistics: The phenotype frequencies were calculated by direct count. χ2 test was done to compare the frequency of each antigen among the patients and control group and it was followed by FisherSQs exact test. Relative risk was estimated by using HaldaneSQs method. Results: The result showed that some of the HLA antigens are associated with the schizophrenia and significant increase were observed for HLA A*03 antigen along with the significant decrease for HLA A*25, A*31 and HLA B*51. Conclusions: The study provides the evidence for the possible existence of susceptibility locus for schizophrenia within the HLA region. This preliminary observation may help to understand the etiological basis of this disorder and the study may further strengthen the HLA antigens as the marker for schizophrenia.



How to cite this article:
Singh B, Banerjee S, Bera NK, Nayak CR, Chaudhuri TK. Analysis of the role of human leukocyte antigen class-I genes to understand the etiopathology of schizophrenia.Indian J Psychiatry 2008;50:166-170


How to cite this URL:
Singh B, Banerjee S, Bera NK, Nayak CR, Chaudhuri TK. Analysis of the role of human leukocyte antigen class-I genes to understand the etiopathology of schizophrenia. Indian J Psychiatry [serial online] 2008 [cited 2019 Nov 19 ];50:166-170
Available from: http://www.indianjpsychiatry.org/text.asp?2008/50/3/166/43625


Full Text

 Introduction



Schizophrenia is a severely debilitating neuropsychiatric disorder characterized by "disturbances of thought, auditory hallucinations and multiple delusions". [1] It affects 1% of the worldwide population. [2] The essential biological pathology of schizophrenia ia partially understood till to date. [3] However, there is substantial evidence to indicate a major genetic component. [4],[5] Different chromosomes have been pinpointed as harbouring genes involved in the pathogenesis of schizophrenia. [6] A susceptibility locus has been identified on chromosome 6. [7],[8] Several researches have also found evidence for schizophrenia vulnerability genes on chromosome 6p close to the HLA genetic region by linkage analysis. [9] HLA and schizophrenia was first reviewed by Mc Guffin (1979), [10] who commented that the MHC was a logical place in which to search for genetic markers for schizophrenia because schizophrenia was similar to diseases for which HLA association had been established in that it was familial, had an imperfectly understood etiology, and had a postulated autoimmune pathogenesis. [11]

The first HLA association study of schizophrenia was reported by Cazzullo et al ., in 1974. [12] More than 60 association studies have been reported since then. [13] The details of past association studies is given in [Table 1].

Past association studies with various Class I and Class II alleles yielded inconsistent results [14] except HLA-A*9 (now subdivided into A*23/A*24). [15] In different ethnic population, associations have been found for HLA-A9, [16] HLA-A23, [17] HLA-A*24, [18] HLA-A*1, [19] HLA-A*2, HLA-A*3, HLA-A*11, HLA-B*17, HLA-B*27, HLA-B*8 and Cw 2, [20] HLA-A*3. [21] The reason for the inconsistencies include the diagnostic methods, particularly in early studies , are imprecise and vary greatly. [22] The majority of the previous association studies were carried out using serological typing techniques [microlymphocytotoxicity testing] [23] , which have been found to be inaccurate, with 7-25% misassignment errors [24] compared with the DNA based techniques (polymerase chain reaction (PCR) and sequence specific oligonucleotide probes (SSOP). The source of controls is not always described in sufficient detail to ensure that results are not simply due to population stratification. Significant results are not always corrected for the number of statistical tests performed. [25]

The present study has been carried out to investigate the association of HLA Class I alleles in Schizophrenia with the help of DNA-based typing method in well-characterized sample of ethnically matched patients and controls. The study may help to identify disease-specific susceptibility (risk) and protective markers that can be used in immunogenetic profiling, risk assessment and therapeutic decisions. Further, the study may refine already known associations in the light of modern DNA based HLA typing method.

 Materials and Methods



We studied 50 India-born schizophrenic patients residing in and around Siliguri subdivision of West Bengal, referred to the psychiatric outpatient department (OPD) of Psychiatry, North Bengal Medical College and Hospital. Three major selection criteria were considered for selection of schizophrenic group; (i) unrelatedness of individuals from each other, (ii) resident of the state of West Bengal and (iii) subjects satisfying DSM IV [3] diagnostic criteria for schizophrenia . The exclusion criteria followed in the present study include; (i) history of substance abuse, (ii) presence personality disorder, (iii) presence of dementia and mental retardation. The patients considered for the present study were belonging to the Bengali, Nepali, Bihari and some tribal community. They were diagnosed independently by two psychiatrists using Structured Clinical Interview [26] and according to the standard diagnostic criteria of DSM IV and assessed by the Brief Psychiatric Rating Scale (BPRS). [27] The present study comprise of 45 Paranoid, 2 Residual, 2 Undifferentiated and 1 disorganised schizophrenic patients. Considering the small number of different subtypes of schizophrenic patients in this study (except Paranoid), we have considered schizophrenic patients as a whole. Some of the demographic variables which have been studied in the patient group are given in the [Table 2].

A total number of 50 ethnically matched healthy individuals were considered as controls. To avoid the spurious associations resulting from population stratification great care was taken. The following criteria were strictly followed for the selection of controls, (i) same ethnic group as the patients, (ii) sex and age matched with patients, (iii) absence of family history of autoimmune or psychiatric disorder, (iv) recent history of intercurrent infection and allergies, (v) unrelatedness of individuals from one another, (vi) no history of any substance abuse. All the participants provided their written consent for giving the blood sample after the study procedures were explained.

Methodology

The blood was drawn by vein puncture method and EDTA was added as anticoagulant. DNA was extracted from peripheral mononuclear cells of the blood by the Phenol Chloroform method. The typing of HLA Class I was performed by PCR-SSP technique. The typing and sequence information of primers were taken from Bunce et al ., (1995). [28] The primers, Taq polymerase, nucleotides etc. were obtained from Bangalore Genei, India. In general 25l of reaction mixture include 1x PCR buffer, 200M of each of dNTP, 1.5mM MgCl2, 0.4M of forward and reverse primers, 100ng of genomic DNA and 1unit of Taq polymerase. The amplifications were accomplished on a thermal cycler (Perkin Elmer, USA). PCR reaction are subjected to 30cycles, each consisted of 94C for 30s, 60C for 1min. and 72C for 1min. with initial denaturation step of 2min and final extension of 2min.

Statistical analysis

The phenotype frequencies were calculated by direct count. χ2 test was performed to compare the frequency of each antigen among the patient and control group followed by Fisher's exact test. Since testing for a large number of antigens can reveal at least one positive association where none really exists, the p values from each Fisher's exact test had to be less than the Bonferroni p [0.05 divided by the number of antigens tested which equals to 0.003125] to be called statistically significant. [21] Relative risk was estimated by using Haldane's method (1956). [29]

 Results and Discussion



The incidence and frequency of HLA Class I antigens among patients and control has been presented in [Table 3]. There was a significantly higher frequency of HLA-A*03 (χ2 =11.458, p =1.155e-4) in patients than the control groups. On the other hand HLA-A*25 (χ2 =13.619, p =9.185e-5), A*31 (χ2 =22.562, p =8.793e-8) and B*51 (χ2 =40.047, p =1.604e-12) showed lower value significantly even after the Bonferroni correction. Though A*02 (χ2 =6.052, p =6.699e-3)showed lower frequency and B*07 (χ2 =4.069, p =2.035e-2) and B*42 (χ2 =4.522, p =1.632e-2) showed higher frequency they were not found to be significant after the Bonferroni correction.

A significant higher frequency of HLA-A*03 observed in the present study is in accordance with the previously reported study by Debnath et al. [21] which is also in accordance with the study of Rudduck et al ., (1984a, 1984b) [30] in Swedish population. Although the association was found to be significantly higher, the present study did not reveal very strong association as it has been reported earlier.

On the other hand, in the present study A*25, A*31 and B*51 showed significantly lower negative value which is the unique finding of the present study. Among these alleles, A*31 and B*51 showed strong negative associations (RR=0.014 and RR=0.006 respectively). The increased frequency of A*11 found in the previous study was not reproducible in the present study. Apart from this, several other alleles like B*7 and B*42 showed higher value but were not statistically significant. We also observed a negative association of A*2 but the association was not found to be significant which was in accordance with the findings of Debnath et al. [21] But the finding was unlike the previous findings by Luchins et al ., (1980) [31] which showed positive association of A*02 with schizophrenia in African-USA population. However, we have not found association between HLA-A*23 and A*24 in our study as has been reported by previous studies.

Many microbial factors have been implicated in the pathogenesis of schizophrenia, but so far each microbial factor has been identified in a relatively small subgroup of patients. [32],[33] The heterogeneity of these microbial factors is also reflected by the associations with different HLA loci and their alleles. [34] Polymorphic HLA molecules process, select and present degraded microbial proteins. [35],[36] The set of inherited HLA alleles determines susceptibility or resistance to particular microbes. [34]

The analysis of the demographic variables suggests the present schizophrenic population is not in equal composition for the different ethnic group. The study comprises more number of Bengali populations. However, as mentioned earlier they were strictly matched according to their ethnicity, age and sex with the patients. The study comprise of higher number of male schizophrenics, which suggest the higher vulnerability of men to this disorder, at least in this region. The higher number of married patients in this study may be due to the strict social customs and strong social bondage of the Indian society.

The present study supports earlier finding of association of HLA-A*03 with schizophrenia along with the negative association of some more alleles, which is the new finding of the present study. However, it is too early to speculate the exact mechanism of the association. The result is preliminary and so far not correlated with the parameters like birth status, viral infections, prenatal infections, etc. However, this study provides the evidence for the possible existence of a susceptibility locus for schizophrenia within the HLA region. Given the size of our sample the result of our finding should be interpreted with caution. The present study needs to be replicated in the large sample size to strengthen our hypothesis of genetic association of HLA Class I antigen with schizophrenia.

 Acknowledgment



This work was supported financially by UGC. We are grateful for the assistance provided by the doctors of Department of Psychiatry, North Bengal Medical College.

References

1Shaw SH, Kelly M, Smith AB, Shields G, Hopkins PJ, Loftus J, et al . A genome-wide search for Schizophrenia susceptibility genes. Am J Med Genet 1998;81:364-76.
2Sawa A, Syndar SH. Schizophrenia: Diverse approaches to a complex disease. Science 2000;296:692-5.
3American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). 4th ed. Washington, DC: APA; 1994.
4Gottesman I I, Shields J. Schizophrenia-the epigenetic puzzle. Cambridge MA: Cambridge University Press; 1982.
5Kendler KS, Diehl SD. The genetics of Schizophrenia: A current, genetic epidemiologic perspective. Schizophr Bull 1993;19:261-85.
6Barondes SH, Alberts BM, Andreassen NC, Bargmenn C, Benes F, Goldman-Rokic P, et al. Workshop on Schizophrenia. Proc Natl Acad Sci USA 1997;19:1612-4.
7Gibson S, Hawi, Straub ER, Walsh D, Kendler KS, Gill M. HLA and schizophrenia: refutation of reported associations with A9 (A23/A24), DR4 and DQβ1*0602. Am J Med Genet 1999; 88:416-21.
8Schwab SG, Hallmeyer J, Greimann J, Lerer B, Albus M, Borrmann-Hassenbach M, et al. Investigation of Linkage and Association/Linkage disequilibrium of HLA A-, DQA1-, DQB1- and DRB1- alleles in 69 sibpair- and 89 Trio Families with Schizophrenia. Am J Med Genet 2002;114:315-20.
9Schwab SG, Albus M, Hallmeyer J, Honig S, Borrmann M, Lichtermann D, et al. Evalution of susceptibility gene for schizophrenia on chromosome 6p by multipoint affected sib-pair linkage analysis. Nat Genet 1995;11:325-7.
10McGuffin P. Is schizophrenia an HLA associated disease? Psychol Med 1979;9:721-8.
11Burch PR. Schizophrenia: Some new aetiological considerations. Br J Psychiatry 1964;110:819-96.
12Cazzullo CL, Smeraldi E, Penati G. The leucocyte antigen system HL-A as possible genetic marker of schizophrenia. Br J Psychiatry 1974;125:612-5.
13Wright P, Nimgaonkar VL, Donaldson PT, Murray RM. Schizophrenia and HLA: A review. Schizophr Res 2001;47:1-12.
14Nimgaonkar VL, Ganguli R, Rudert WA, Vavassori C, Rabin BS, Trucco M. A negative association of schizophrenia with an allele of the HLA DQβ1 gene among African-Americans. Am J Med Gent 1992;8:199-209.
15McGuffin P, Owen MJ, Farmer AE. The genetic basis of schizophrenia. Lancet 1995;346:678-82.
16Goudemand M, Goudemand J, Parquet PJ, Fontan M. Schizophrenic psychoses and HLA antigens. Personal data and review of the literature. Encephale 1981;7:609-22.
17Ivαnyi P, Dr φes J, Schreuder GM, D'Amaro J, van Rood JJ. A search for association of HLA antigens and with paranoid schizophrenia. Tissue Antigens 1983;22:186-93.
18Asaka A, Okazaki Y, Namura I, Juji T, Miyamajo M, Ishakawa B. Study of HLA antigens among Japanese schizophrenics. Br J Psychiatry 1981;138:498-500.
19Lahdelma L, Ahonas A, Anderson LC, Huttunen M, Sarha S, Kossimies S. Association between HLA-A1 alleles and schizophrenia gene(s) in patients refractory to conventional neuroleptics but responsible to clozapine medication. Tissue Antigen 1998;51:200-3.
20Rudduck C, Franzen G, Low B, Rorsman B. HLA antigens in patients with and without a family history of schizophrenia. Hum Hered 1984; 34:291-6.
21Debnath M, Das SK, Bera NK, Nayak CR, Chaudhuri TK. Study of HLA-linked genes in paranoid schizophrenia in an Indian Bangalee population. Int J Hum Genet 2005;5:273-7.
22Singer L, Mayer S, Tongio MM, Roos M, Danion JM, Bernard H, et al. Frequencies of HLA-A, C and Bf antigens in schizophrenic patients originated from Alsace (author's transl). Encephale 1982;8:9-15.
23Joysey VC, Woolf E. HLA-A, B and C antigens, their serology and cross-reaction. Br Med Bull 1978;34:217-22.
24Opelz G, Mytilneos J, Scherer S, Dunckely H, Trejaut J, Chapman J, et al. Survival of DNA HLA-DR typed and matched cadaver kidney transplants. Lancet 1991;338:461-3.
25Hawi Z, Gibson S, Straub RE. Walsh D, Kendler KS and Gill M. Schizophrenia and HLA: No association with PCR-SSOP typed classical loci in a large Irish familial sample. Am J Med Gent.1999;88:422-429.
26First MB, Spitzer RL, Gibbon M, Williams JB. Structured clinical interview for DSM-IV axis I disorders, Patient edition (SCID-P), Verson 2. New York: New York State Psychiatric Institute, Biometrics Research; 1996.
27Overall JE, Gorham DR. The brief psychiatric rating scale. Arch Gen Psychiatry 1962;16:146-51.
28Bunce M, O'Neill CM, Barnardo MC, Krausa P, Browning MJ, Morris PJ, et al . Phototyping: Commprehensive DNA typing for HLA-A, B, C, DRB1, DRB3, DRB4, DRB5 and DQB1 by PCR with 144 primer mixes utilizing sequence specific primers (PCR-SSP). Tissue Antigens 1995;46:355-67.
29Haldane JB. The estimation and significance of the logarithm of a ratio of frequencies. Ann Hum Genet 1956;20:309-11.
30Rudduck C, Franzen G, Low B, Rorsman B. HLA antigens and clinical subgroups of schizophrenia. Hum Hered 1984a;34:18-26.
31Luchins D, Torrey EF, Weinberger DR, Zalcman S, De Lisi L, Johnson A, et al. HLA antigens in schizophrenia: Differences between patients with and without evidence of brain atropy. Br J Psychiatry 1980;136:243-8.
32Bechter K, Herzog S, Estler HC, Schuttler R. Increased psychiatric comorbidity in Borna disease virus seropositive psychiatric patients. Acta Psychiatr Belg 1998;98:190-201.
33Karlsson H, Bachmann S, Schroder J, McAuthur J, Fuller EF, Yolken RH. Retroviral RNA identified in the cerebrospinal fluids and brains of individuals with schizophrenia. Proc Natl Acad Sci USA 2001;98:4634-9.
34Laumbacher M, Muller N, Bondy B, Schlesinger B, Gu S, Fellerhoff B, et al. Significant frequency deviation of the Class I polymorphism HLA-10 in schizophrenic patients. J Med Genet 2003;40:217-9.
35Solheim JC, Carreno BM, Hansen TH. Are transporters associated with antigen processing (TAP) and tapasin Class I MHC chaperones? J Immunol 1997;158:541.
36Ciechanover A. The ubiquitin-proteasome proteolytic pathway. Cell 1994;79:13.