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Biomedical subjects

J Mila

Publications and source records attributed to J Mila.

8 recordsLinked to original sources
PubMed2005

Diagnostic value of C4d in renal allograft biopsies in different clinical settings: absence of C4d in grafts from non-heart-beating donors.

UNLABELLED: Humoral mechanisms of rejection after kidney transplantation (TX) can be identified through the detection of diffuse complement C4d deposits in peritubular capillaries (PTC) in graft biopsies or donor-specific antibodies (DSA) in serum samples. It has been hypothesized that ischemic injury in the graft may facilitate humoral responses. Kidney grafts from non-heart-beating donors (NHBD) present more often severe ischemia lesions than grafts from heart-beating or living donors. METHODS: We reviewed kidney TX biopsies performed from May 2002 to November 2004 with special interest paid to recipients from NHBD. We checked corresponding frozen tissue for the detection of C4d in PTC using immunofluorescence with a monoclonal antibody against C4d. We also collected post-TX contemporaneous DSA data, either flow crossmatches or cytotoxic PRA. RESULTS: During this period, we performed 22 kidney TXs from NHBD of a total of 326 kidney TX (either single or combined with other grafts). Nine patients of this group underwent 12 biopsies for delayed graft function over 15 days or deteriorating scans. All biopsies showed acute tubular necrosis, but one also presented IA Banff acute rejection and another one had neutrophils in PTC. Frozen tissue from these 12 biopsies did not have diffuse C4d deposits in PTC. Serum samples of seven of nine patients were available: four had negative DSA flow crossmatches and three had 0% PRA within the same period. We diagnosed acute humoral rejection (AHR) in 13 patients-with acute renal dysfunction, C4d in biopsies and DSA after kidney TX-of 38 with high clinical suspicion for AHR. We detected C4d in seven biopsies of 30 patients performed more than 6 months after TX. CONCLUSIONS: Severe ischemic injury does not necessarily determine the activation of humoral mechanisms of rejection mediated through DSA. Therefore, C4d is extremely interesting for the identification of humoral rejection in any clinical setting after kidney TX.

Antibody Formation↗
PubMed2003

Diagnosis and treatment of acute humoral rejection after kidney transplantation: preliminary experience.

BACKGROUND: Acute humoral rejection, or rejection associated with de novo production of anti-HLA donor-specific antibodies (DSA) after kidney transplantation (KTx), is a clinicopathologic entity that is not completely understood. Recent studies have proposed criteria for its diagnosis, including: (1) steroid-resistant acute dysfunction; (2) positive post-Tx donor-specific crossmatch (XM); and (3) widespread C4d deposits in peritubular capillaries (PTC) upon renal biopsy. METHODS: During 2002, prospective screening for AHR was established at our unit, seeking DSA post-KTx in selected cases of steroid-resistant acute rejection or acute dysfunction in high-risk sensitized or re-Tx patients. Frozen donor lymphocytes were used for post-Tx flow cytometry (FC) XM and high-definition flow PRA for patients with no frozen donor cells. We treated patients diagnosed with DSA using plasma exchange and polyclonal immunoglobulin. RESULTS: Post-Tx DSA studies were performed in 9 of 94 patients transplanted during 2002. We detected DSA post-Tx in 3 of 9 recipients: 2 by FCXM and 1 using high-definition flow PRA. Two were highly sensitized pre-Tx, but the third patient was a 70-year-old woman receiving a first Tx (PRA=0%). All 3 recipients presented with severe steroid-resistant acute renal dysfunction during the first 2 weeks post-Tx. Biopsies showed some features of AHR (neutrophils in PTC); 1 case showed no signs of concomitant cellular rejection. All rejection episodes were treated successfully (XM became negative and renal function recovered) by combining plasma exchange and polyclonal immunoglobulin. CONCLUSIONS: The use of specific tools, like the crossmatch, in cases of acute, steroid-resistant renal graft dysfunction is important to identify and treat otherwise undetected humoral mechanisms of rejection.

Acute Disease↗
PubMed2003

Outcome of simultaneous liver-kidney transplantation in highly sensitized, crossmatch-positive patients.

BACKGROUND: In simultaneous liver-kidney transplantation (SLKT), the liver has been described to protect the kidney from rejection, and acceptable results are possible despite a pretransplant positive crossmatch. At our center, 21 SLKT have been performed since 1993, 2 of them against a positive crossmatch. OBJECTIVES: In this study we retrospectively analyzed two cases of SLKT after positive pretransplant crossmatch. METHODS: Two highly sensitized women (30 and 52 years) with hepatic cirrhosis VHC on hemodialysis after a first KT failure were assessed. Pretransplant panel reactive antibodies (PRA) by complement dependent cytotoxicity NIH (CDC) were 81% and 99% respectively. Both patients received a SLKT. CM was performed at pretransplant and 24 and 48 hours posttransplant by CDC and by flow cytometry with double labeling with CD3-PE and antihuman IgG-FITC. Patients received ATG, cyclosporine, and prednisone therapy. RESULTS: CM was positive pretransplant by CDC and flow cytometry. At 48 hours, CDC became almost negative (10%-20% mortality) and flow cytometry became negative. One of the patients experienced an episode of acute rejection at 10 days posttransplant that resolved with steroid pulses. Both patients presently have working grafts 26 and 24 months posttransplant (Cr, 1.1 and 1.5 mg/dL; GOT, 34 and 14 IU/L; GTP, 29 and 12 IU/L; GGT, 9 and 66 IU/L). CONCLUSIONS: Our experience suggests that a positive crossmatch is not an absolute contraindication for SLKT. Good graft and patient survival rates are possible even among highly sensitized patients.

Adult↗
PubMed1999

CD95 expression and function on lymphocyte subpopulations in common variable immunodeficiency (CVID); related to increased apoptosis.

Apoptosis is now recognized as a central process of development and disease, and it has been proposed as one of the mechanisms that may account for the lymphopenia seen in some diseases. In this study we measured spontaneous apoptosis and CD95 expression on different cell subpopulations from CVID patients, using flow cytometric techniques. We divided our patients into two groups according to their CD4+ and CD4+CD45RA+ cell counts. Our results clearly show increased spontaneous apoptosis and CD95 expression on the CD4+ and CD4+CD45RA+ subsets from lymphopenic CVID patients compared with normal subjects and disease controls. Interestingly, our lymphopenic CVID patients presented a profound reduction in absolute counts, mainly affecting the CD4+CD45RA+ subpopulation. We also found a statistically significant direct correlation between absolute numbers of CD4+CD45RA+ T cells and spontaneous apoptosis on the same subset in CVID patients, but attempts to induce CD95-mediated apoptosis were unsuccessful despite increased CD95 expression on CD4+ T cells. These findings suggest that apoptosis could be one of the mechanisms implicated in the significant lymphopenia present in these patients.

Agammaglobulinemia↗
PubMed1993

CDw50 and ICAM-3: two names for the same molecule.

CDw50 differentiation antigen is a molecule broadly expressed on hematopoetic cells but not on other cells. Previous experiments showed that CDw50 monoclonal antibodies (mAb) inhibited primary mixed lymphocyte culture (MLC). To understand the function of CDw50 better, we purified it and obtained peptide sequence. At the same time, intercellular adhesion molecule (ICAM)-3, the third ligand of lymphocyte function-associated molecule 1, was described by mAb and subsequent cDNA cloning. Immunochemical, functional, and protein sequencing studies show that ICAM-3 and CDw50 are the same glycoprotein, a 120-kDa surface molecule with presumably an important role in the immune responses.

Amino Acid Sequence↗
PubMed1990

Involvement of the CDw50 molecule in allorecognition.

The CDw50 differentiation antigen is defined by 101-1D2 and 140-11 monoclonal antibodies (mAb), both produced and characterized in our laboratory. This molecule is broadly expressed on hematopoetic cells but not on other cells. In this report we show that these 2 mAb recognize different epitopes of the same molecule, which are resistant to neuraminidase and proteases. We also demonstrate that the CDw50 antigen is expressed on thymocytes and T lymphocytes as an N-glycosylated glycoprotein monomer with a relative molecular weight (Mr) of 130,000 daltons with intrachain disulfide bonds, and that this molecule is resistant to treatment with phosphatidylinositol (PI) phospholipase C and therefore probably not PI-anchored to the membrane. CDw50 is a poorly or non-constitutively phosphorylated molecule that becomes phosphorylated by treatment with phorbol 12-myristate 13-acetate (PMA) of peripheral blood mononuclear cells (PBMC). The addition of affinity-purified CDw50 mAb inhibits primary mixed lymphocyte culture (MLC) but not secondary MLC, cytotoxicity or proliferation induced by mitogens. The inhibition of alloreactivity is mediated at the level of both responding and stimulator cells.

Antibodies, Monoclonal↗
PubMed1984

An antiplatelet monoclonal antibody that inhibits ADP and epinephrine-induced aggregation.

A monoclonal antibody (Mab) named EDU-3, was produced by fusing splenocytes from one Balb/c mouse, immunized with a mixture of platelets and non-T cells from heparinized human peripheral blood, with the HAT-sensitive myeloma line P3-NS1/1.Ag4.1. By indirect immunofluorescence (IF) it was seen that this Mab reacted with all normal human platelets and bone marrow megakaryocytes, but did not react with lymphoid cells from normal donors, or platelets from Glanzmann's thrombasthenia (GT) patients. Immunoprecipitation and SDS-PAGE experiments demonstrated that this Mab recognized an epitope on the IIb-IIIa glycoprotein complex (GPC). EDU-3 inhibited platelet aggregation and release of ATP induced by ADP and epinephrine. Aggregation induced by arachidonic acid, ristocetin and bovine factor VIII were not inhibited by EDU-3. The difference between EDU-3 and other Mab directed against the IIb-IIIa GPC is discussed.

Adenosine Diphosphate↗