Introducing a new experimental islet transplantation model using biomimetic hydrogel and a simple high yield islet isolation technique

Background: Islet transplantation could be an ideal alternative treatment to insulin therapy for type 1 diabetes Mellitus [T1DM]. This clinical and experimental field requires a model that covers problems such as requiring a large number of functional and viable islets, the optimal transplantation site, and the prevention of islet dispersion. Hence, the methods of choice for isolation of functional islets and transplantation are crucial

Methods: The present study has introduced an experimental model that overcomes some critical issues in islet transplantation, including in situ pancreas perfusion by digestive enzymes through common bile duct. In comparison with conventional methods, we inflated the pancreas in Petri dishes with only 1 ml collagenase type XI solution, which was followed by hand-picking isolation or Ficoll gradient separation to purify the islets. Then we used a hydrogel composite in which the islets were embedded and transplanted into the peritoneal cavity of the streptozotocin-induced diabetic C57BL/6 mice

Results: As compared to the yield of the classical methods, in our modified technique, the mean yield of isolation was about 130-200 viable islets/mouse pancreas. In vitro glucosemediated insulin secretion assay indicated an appropriate response in isolated islets. In addition, data from in vivo experiments revealed that the allograft remarkably maintained blood glucose levels under 400 mg/dl and hydrogel composite prevents the passage of immune cells

Conclusion: In the model presented here, the rapid islet isolation technique and the application of biomimetic hydrogel wrapping of islets could facilitate islet transplantation procedures

Study of KIR expression and HLA ligands in cd56+ lymphocytes of drug resistant tuberculosis patients

Analysis of receptor-ligand interactions in the context of diseases necessitates to understand how HLA-KIR genotypes function in diseases. Although CD56+ lymphocytes are derived from multiple lineages, they share a functional association with immunosurviellance and antimicrobial responses. The present study aimed to determine whether KIR phenotype in CD56 lymphocytes and corresponding HLA-class 1 ligands are associated with multidrug resistance tuberculosis [MDR-TB]. We compared the frequencies of HLA-C and HLA-BW4 genes, the expression of KIRs 2DL1/2DS1, 2DL2/2DL3, 3DL1, and 2DS4 and the combinations of HLA/KIR in 32 Nifamycin and Isoniazid-resistant TB with those in 68 drug non resistant [NR] sputum smear positive pulmonary TB patients. PCR-SSP and flow cytometry were performed for HLA and KIRs typing, respectively. We showed no significant differences between inhibitory or activating KIRs as well as HLA ligands in MDR TB patients compared with NR-TB. The combinations of inhibitory KIR-HLA ligands in MDR-TB were much more prevalent, but not statistically significant than in NR patients [p=0.07]. The frequency of MDR patients with all HLA-C and HLABW4 ligands was higher than NR-TB [p<0.009]. Conversely, the percentage of MDR patients having only one kind of HLA gene was significantly lower than NR-TB [p<0.01]. We conclude that the expression of inhibitory KIRs with corresponding HLA ligands genes, and/or co-existence of three HLA class 1 ligands for inhibitory KIRs may be associated with drug resistance in pulmonary tuberculosis

Inhibitory killer cell immunoglobulin-like KIR3DL1 in combination with HLA-B Bw4[iso] protect against ankylosing spondylitis

The HLA class I molecules serve as ligands for both T cell receptors and killer cell immunoglobulin-like receptors [KIRs]. We investigated the HLA-C and HLA-Bw4 alleles as well as KIRs expression on CD56 positive lymphocytes to evaluate whether these genes and molecules could influence Ankylosing spondylitis [AS] susceptibility, alone or in combination. We typed 40 AS patients and 40 normal controls for HLA-C asn[80] [group 1] and HLA-C lys[80] [group 2], HLA-B Bw4[thero], HLA-B Bw4[iso] and HLA-A Bw4 alleles by PCR-SSP method. We also assessed the expression of KIR2DL1/2DS1, KIR2DL2/2DL3, KIR3DLI and KIR2DS4 by flow cytometry. The Pearson chi-square or Fisher exact test was performed for statistical analysis. The frequency of HLA-B Bw4[iso] but not HLA-B Bw4[thero] and HLA-A Bw4, ligand for the inhibitory KIR3DL1, was significant reduced in AS patients as compared with controls [p<0.01]. No significant differences were observed in gene carrier frequencies of HLA-C group 1 and 2 between AS and controls. Although no differences were found in the expression of KIR receptors between AS and normal was reduced in patients with AS compared to healthy controls [p<0.009]. We conclude that HLA-B Bw4[iso], the ligand of inhibitory KIR3DL1, with and without the expression of KIR3DL1 might be involved in protection against AS. Our results suggest that besides the HLA and KIR genotype, expression levels of KIRs may be involved in the pathogenesis of AS disease

KIR2DS3 is associated with protection against acute myeloid leukemia

Interaction between killer cell immunoglobulin-like receptors [KIR] and human leukocyte antigen [HLA] class I molecules is important for regulation of natural killer [NK] cell function. The aim of this study was to investigate the impact of compound KIR-HLA genotype on susceptibility to acute leukemia. Cohorts of Iranian patients with acute myeloid leukemia [AML; n=40] and acute lymphoid leukemia [ALL; n=38] were genotyped for seventeen KIR genes and their three major HLA class I ligand groups [C1, C2, Bw4] by a combined polymerase chain reaction-sequence-specific primers [PCR-SSP] assay. The results were compared with those of 200 healthy control individuals. We found a significantly decreased frequency of KIR2DS3 in AML patients compared to control group [12.5% vs. 38%, odds ratio=0.23, p=0.0018]. Also, the KIR3DS1 was less common in AML group than controls [27.5% vs. 44.5%, p=0.0465, not significant after correction]. Other analyses including KIR genotypes, distribution and balance of inhibitory and activating KIR+HLA combinations, and co-inheritance of activating KIR genes with inhibitory KIR+HLA pairs were not significantly different between leukemia patients and the control group. However, in AML patients a trend toward less activating and more inhibitory KIR-HLA state was observed. Interestingly, this situation was not found in ALL patients and inhibition enhancement through increase of HLA ligands and inhibitory combinations was the main feature in this group. Our findings may suggest a mechanism for escape of leukemic cells from NK cell immunity

Elevation of CD56[bright]CD16[-] lymphocytes in MDR pulmonary tuberculosis

Protective immune responses induced in the majority of people infected with Mycobacterium tuberculosis enable them to control TB infection. The aim of this study was to investigate CD56 and CD16 positive peripheral blood mononuclear cells [PBMCs] and leukocyte subsets from multi-drug resistant pulmonary tuberculosis [MDR-TB], and compare them with nonresistant [NR] TB patients and healthy controls. 13 MDR-tuberculosis patients, 20 NR-TB individuals and 40 healthy subjects were included. Peripheral blood mononuclear cells were double stained with fluorochrome conjugated antibodies against CD56 and CD16 cell surface markers. The phenotype of positive cells was then analyzed by flow cytometry and the percentages of CD56[+] CD16[+], CD56[-] CD16[+], CD56[dim]CD16[ +/- ], and CD56[bright]CD16[ +/- ] subsets were calculated. There was a significant decline in the percentage of CD56[]+CD16[+] lymphocytes in both MDR and NR-TB patients compared with healthy controls. We also observed lower proportions of CD56[dim]/[bright]CD16[+] in addition to higher percentages of CD56dim/brightCD16-subsets in all TB patients [p

predictive value of HLA-DR matching and cytokine gene polymorphisms in renal allograft acute rejection: a living-unrelated donor [LURD] study

In addition to Human Leukocyte Antigens [HLA] compatibility, gene polymorphisms in cytokines might also be important in the quality of allogeneic immune response. To evaluate the influence of HLA-DR matching and a number of cytokine gene polymorphisms on acute rejection after living-unrelated donor [LURD] kidney transplantation. A total of 42 renal transplants performed at Hashemi Nejad Kidney Hospital [Tehran/Iran] and followed up for 3 months post-transplantation were included. Using PCR-SSP, HLA-DR alleles [DR1-18] of recipients and donors and gene polymorphisms in TNF-a, TGF-b1, IL-10, IL- 6, and IFN-g of recipients were determined. Acute rejection was observed in 11[26.2%] of renal recipients. The frequency of one and two HLA-DR mismatches in rejector group was 2[18.2%] and 9[81.8%] and in non-rejector group was 13[41.9%] and 17[54.8%], respectively. HLA-DR incompatibility was not significantly higher in rejector [1.82 +/- 0.40] compared with non-rejector [1.52 +/- 0.57] recipients [P=0.069] and more than half of non-rejectors had ompletely mismatched HLA-DR antigens with donors. Polymorphisms associated with the mentioned cytokines had no correlation with acute rejection. The predictive value of HLA-DR mismatching for acute rejection is not as prominent in LURD kidney transplantation as in the cadaveric one. In addition, we failed to demonstrate an association between combined cytokine genotypes and HLA-DR matching with acute rejection. Further and more detailed immunogenetic investigations are required in order to have a better prediction of the transplant outcome

Microchimerism and renal transplantation: doubt still persists

Background: The Presence of donor leukocytes in recipients of organ allograft has been shown even several years after transplantation. However, it remains unclear whether this donor cell microchimerism plays an effective role in allograft acceptance or is simply a consequence of immunosuppressive conditions in recipients

Objective: To study microchimerism in a group of kidney transplant recipients

Methods: In this study, the Peripheral Blood Microchimerism [PBM] after renal transplantation was retrospectively evaluated in 32 male-to-female recipients of living [unrelated] and cadaveric donor renal transplants. Using a Nested Polymerase Chain Reaction [Nested-PCR] amplification specific for SRY region of the Y chromosome, microchimerism was detected with a sensitivity of 1:1000000. Recipients were classified and compared according to the presence of PBM, acute and chronic rejection episodes, type of allotransplant, recipient and donor age at transplantation, previous male labor or blood transfusion, allograft function [serum creatinine level], and body mass index

Results: Among 32 recipients, 7 [21.9] were positive for PBM in multiple testing at different post-transplantation times. All microchimeric recipients had received kidney from living-unrelated donors. No significant difference was observed with regard to other parameters mentioned above. In addition, acute rejection rate in the microchimeric group was 3 [42%] versus 4 [16%] in the nonmicrochimeric recipients [not significant]

Conclssion: Our results demonstrate better establishment of microchimerism after living donor kidney transplantation. However, concerning the true effect of microchimerism after renal transplantation doubt still persists; and it seems that microchimerism alone has no major protective role in renal allograft survival