Search PubMed⌕ Search

Biomedical subjects

N K Mehra

Publications and source records attributed to N K Mehra.

At least 127 records · Page 7Linked to original sources
PubMed1981

Autoimmunity in type I (insulin-dependent) diabetes mellitus in North India.

Pancreatic islet cell, thyroid, gastric parietal cell, and adrenal autoantibodies were studied in 110 young insulin-dependent diabetics (type I; IDDM), 12 non-insulin-dependent diabetics (NIDDM), 26 patients with pancreatic diabetes, and 123 age- and sex-matched healthy controls. All the patients were aged 30 years or under at the onset of diabetes. Islet cell antibody was found in 31% of the patients with IDDM, but in only one patient with NIDDM, one patient with pancreatic diabetes, and one healthy control subject. Thyroid, parietal cell, and/or adrenal antibodies were present in 26% of the IDDM patients, 17% of the NIDDM patients, 12% of the patients with pancreatic diabetes, and 19% of the control subjects. There was no association between the presence of islet cell antibody and other organ-specific autoantibodies and any particular HLA phenotype. Data from the North Indian study have been compared with those from other populations of the world, similarities and differences have been brought out, and their significance has been discussed. The relative contribution of the autoimmune component in the etiopathogenesis of different forms of diabetes mellitus varies among the different populations of the world, accounting to some extent for the observed differences in incidence and clinical profiles.

Adrenal Glands↗
PubMed1981

HLA antigens in type I (insulin-dependent) diabetes mellitus in North India.

Fifty-four North Indian patients with Type I (Insulin-Dependent) diabetes mellitus who were aged 30 yr or under at onset were HLA-typed. The frequencies of HLA-BW21, BW35, and A28 were significantly increased and that of HLA-B7 was significantly reduced. On correction for the number of antigens tested, only the difference observed with HLA-BW21 for positive association and B7 for negative association remained statistically significant. HLA-B8, B15 and B18 did not demonstrate any significant association with IDDM in this series of patients. The results of the study further emphasize the well recognized race specificity in HLA antigen distribution in normal population as well as disease states. This association of HLA-BW21 with IDDM is the first report from North India.

Autoantibodies↗
PubMed1981

HLA and sporadic tuberculoid leprosy: a population study in Maharashtra, India.

A population study to test whether associations between HLA and sporadic--i.e. non-familial--tuberculoid leprosy exist was undertaken in a hyperendemic area in India. Since previous family studies in the same area had shown both non-random haplotype segregation in the family members affected with tuberculoid leprosy and the preferential segregation of HLA-DR2 into tuberculoid leprosy patients, an increased frequency of DR2 among the "sporadic" patients was expected. However, no heterogeneity for HLA was detected between patients and controls. These findings could indicate that tuberculoid leprosy is a heterogeneous disease with regard to genetic background.

Female↗
PubMed1980

HLA segregation of tuberculoid leprosy: confirmation of the DR2 marker.

Families with multiple cases of leprosy were tested for HLA (histocompatibility leukocyte antigen)-linked control of susceptibility to tuberculoid leprosy and association with HLA-DR2. Thirty-one non-HLA genetic markers were also examined for indications of non-HLA-linked genetic factors that might control susceptibility to tuberculoid leprosy. A significant (P = 0.002) preferential inheritance of HLA-DR2 by siblings affected with tuberculoid leprosy, but not by healthy siblings nor by siblings affected with lepromatous leprosy, was observed. In addition, combined family data showed a significant (P less than 0.0025) excess of identical HLA haplotypes inherited from healthy parents by siblings affected with tuberculoid leprosy. Segregation on non-HLA polymorphisms did not deviate significantly from what would have occured randomly. These data are compatible with a recessive inheritance of HLA-linked susceptibility to tuberculoid leprosy. The preferential segregation of DR2 observed in children with tuberculoid leprosy (P less than 0.001 for the combined data from India) indicates that the HLA-linked susceptibility gene is either DR2 or in linkage disequilibrium with it.

Epitopes↗
PubMed1980

HLA-linked control of susceptibility to tuberculoid leprosy and association with HLA-DR types.

In an attempt to confirm an HLA-linked effect on the course of Mycobacterium leprae infection observed in families from Surinam (South America), we conducted a similar family study in an endemic area in India. We observed a significant (P less than .05) excess of identical HLA-GLO haplotypes only from healthy parents among siblings affected with tuberculoid leprosy. Compared with healthy controls, unrelated patients with tuberculoid leprosy (n = 15) showed a significant heterogeneity at the HLA-DR locus (P less than .05). This heterogeneity was caused by an increased frequency of HLA-DRw2 (.93 versus .53, P less than .05), particularly of DRw2 homozygotes (.53 versus .11, P less than .005), and a decreased frequency of HLA-DRw6 (.07 versus .58, P less than .005). We observed a significant (P = .03) preferential segregation of DRw2 from DRw2 heterozygous parents not affected with tuberculoid leprosy to children with the tuberculoid type of the disease. These data confirm an HLA-linked control of susceptibility to tuberculoid leprosy only, and suggest a recessive inheritance of this trait for which HLA-Drw2 appears to be a genetic marker.

Female↗
PubMed1980

Natural suppressor cells in human leprosy: the role of HLA-D-identical peripheral lymphocytes and macrophages in the in vitro modulation of lymphoproliferative responses.

Six families with HLA-D-identical siblings suffering from leprosy were studied. Lymphocytes and macrophages isolated from the peripheral blood were co-cultured with allogeneic, HLA-D-identical cells and stimulated with M. leprae antigens and concanavalin A. Tuberculoid patients had circulating lymphocytes which showed marked functional suppression of lymphoproliferative responses to antigen and mitogen. In contrast, lepromatous patients showed weak lymphocyte suppressor activity. Macrophages derived from responder individuals augmented, while those derived from lepromatous patients inhibited, M. leprae-induced proliferation of lymphocytes.

Antigens, Bacterial↗
PubMed1979

Concanavalin A induced suppressor activity in human leprosy.

Peripheral blood lymphocytes from nine normal subjects and 40 patients with leprosy were pretreated in vitro with Concanavalin A (Con A). Cells from normal subjects pretreated for 24 hours showed consistent and effective generation of suppressive activity which inhibited mitogen induced transformation of autologous lymphocytes. Prolongation of Con A pretreatment to 40 hours resulted in maximal suppressive activity. Tuberculoid leprosy patients had lymphocytes in their blood which on 24 hour pretreatment with Con A exerted suppressive effects markedly greater than the maximal suppression noted with 40 hour pretreated normal lymphocytes. In contrast, untreated patients with polar lepromatous leprosy showed a decrease in suppressive activity which could not be altered by prolongation of Con A pretreatment: the loss of suppressive activity noted in this form of leprosy was restored during erythema nodosum leprosum.

Concanavalin A↗
PubMed1976

An evaluation of the immune state in leprosy.

An evaluation of the immune state in leprosy was done by the application of a system of graft-versus-host reaction. Peripheral blood lymphocytes obtained from patients with different forms of leprosy and from normal healthy individuals were injected intravenously into the irradiated mice. The rate of blast transformation of the donor cells was measured by the radio-active thymidine uptake. The number of cells labelled with tritiated-thymidine was much higher in the normal individuals and patients with tuberculoid leprosy than in the patients with lepromatous leprosy with the borderline group placed in between the two. However, following successful treatment with DDS, an increased responsiveness and active DNA synthesis could be observed in the previously less responsive lepromatous lymphocytes.

Adult↗
PubMed1975

Histocompatibility antigens (HL-A) in leprosy.

HL-A antigens of 70 leprosy patients and 40 normal healthy individuals were determined by the standard microlymphocytotoxicity test. Both lepromatous and non-lepromatous leprosy patients were tested for the presence of 11 HL-A antigens, and the frequency of each specificity was compared with that in a normal population of the same ethnic group. Although the statistical significance of HL-A8 specificity was found to be marginal in lepromatous leprosy patients, when using ordinary 2 times 2 statistics, there did seem to be a decreased frequency of HL-A9 among the non-lepromatous type. Other antigens tested did not reveal any significant differences between the two groups of subjects.

Adult↗
PubMedDate not supplied

Immunologic and immunogenetic studies in rheumatic fever and rheumatic heart disease.

In order to evaluate all the important limbs of the immune system in the same patient population with rheumatic fever (RF) and rheumatic heart disease (RHD) cellular and humoral immune parameters as well as the immunogenetic profile in 265 North Indian patients with RHD were evaluated. They were studied for class in HLA antigens and 165 of them were also evaluated for the class II (DR locus) antigen profile. Data obtained was compared with 400 and 134 healthy controls respectively of the same ethnicity. Humoral immune parameters (Serum immunoglobulins IgG, IgA; Serum complement fractions C3, C4, C3d; circulating immune complexes and B lymphocyte numbers) and cellular immune parameters (total leucocyte and lymphocyte counts; T lymphocyte sub-populations--CD4, CD8 counts; lymphocyte migration inhibition to an extracellular streptococcal antigen, streptolysin 'O') were studied in 23 patients with RF, 21 patients with "inactive" RHD and 20 normal controls. Patients of RHD were noted to have an increased frequency of DR3 (P less than 0.001; Relative risk = 2.3) and a decreased frequency of DR2 (P less than 0.001; Relative risk = 0.3) as compared to the controls. Patients of RF had evidence of an altered regulatory T cell function (increased CD4/CD8 ratio) and decreased cell mediated immunity to streptolysin 'O'. An increased humoral immune response (increased B cell counts, elevated serum IgG, circulating immune complexes and C3d) was noted in patients of RF as well as "inactive" RHD. An integrated pathogenetic model with immune response associated antigens of the DR locus influencing selection of cardiac cross-reactive antigens by the antigen processing macrophages, an altered regulatory T cell function with decreased suppressor T cell activity leading to an abnormal immune response is proposed to explain the pathogenesis of RF.

HLA Antigens↗
PubMedDate not supplied

HLA-B5 and B21 antigens in aortoarteritis.

The distribution of class I HLA antigens (HLA-A, B) were determined in 50 patients of Aortoarteritis in an Indian population. This included 29 females and 21 males. The difference in antigen frequency was observed between patients and controls with reference to HLA-A19, B5 and B21 antigens. A decreased frequency of HLA-A19 was observed in the patients as compared to controls (14% vs 33.25%, X2 = 6.81, P less than 0.025). Of the B locus antigens, an increased frequency of HLA B5 was observed in the patients as compared to controls (48% vs 29.5%, X2 = 6.2, P less than 0.025). HLA-B21 was also increased in the patients as compared to the controls (18% vs 6.5%, X2 = 6.67, P less than 0.025). These data suggest the involvement of genetic factor (s) in the aetiopathogenesis of this disease. Further, the observations indicate that HLA-B5 and B21 may be associated with Aortoarteritis.

Adolescent↗
PubMedDate not supplied

HLA--an overview.

Explore the source record for details and available documents.

Animals↗
PubMedDate not supplied

Functional assessment of immune markers of graft rejection: a comprehensive study in live-related donor renal transplantation.

A better understanding of the immunobiological processes and predictors of graft rejection holds promise for the development of potential therapeutic strategies and also individualization of immunosuppression. The objective of this study is to analyze the clinical relevance of immune parameters such as antidonor antihuman leukocyte antigen (anti-HLA) antibodies, monitoring of cytokines and their receptors on the graft outcome following live-related donor renal transplantation. Flow cytometry-based methods were used to detect antidonor antibodies (flow cytometry crossmatch, FCXM) and intracellular cytokines. Enzyme-linked immunosorbent assay (ELISA) methods were employed to detect anti-HLA class I and class II antibodies and quantitative serum-soluble interleukin-2 receptor (sIL-2R) levels. The data revealed that patients with HLA class I-specific IgG antibody experienced higher acute rejection (AR) episodes at 1 yr in comparison to the antibody negative group (82% vs. 56%, p = 0.01). On the contrary, donor-specific class II antibodies (B+) did not have any influence on the graft survival. However, 15 recipients having both T- and B-cell antidonor antibodies (T+B+) had significantly poor graft survival (60%) as compared to the antibody-negative group (T-B-, 82%, p = 0.05). Additionally, patients having non-donor but HLA-specific antibodies (FCXM-/ELISA+) had poor graft survival as compared to the antibody-negative group (64% vs. 88%, p < 0.05). Further, patients undergoing AR episodes had significantly higher expression of IFN-gamma-producing T cells (19.16 +/- 7.4% median 17.50) as compared to their pre-transplant levels (5.68 +/- 1.63%, Median 5.20) and the non-rejecter group (5.97 +/- 4.39%, median 4.3, p = 0.0004). Similarly sIL-2 was significantly increased in AR episodes during the first month of transplantation (292 +/- 131.5 pmol/L) as compared to those with well-functioning grafts (p = 0.01) and healthy controls (p = 0.001). Evaluation of antidonor antibodies by flow cytometry is found to be relatively more sensitive and a better predictor of graft outcome. Further monitoring of cytokine expression profile of primed peripheral T-helper cells and quantitative analysis of sIL-2R offer additional valuable diagnostic and prognostic tools for follow-up of transplant subjects and a better alternative for functional assessment of immunosuppression.

Antibodies↗