Kay Poulton

Mannose-Binding Lectin Gene Polymorphisms as a Susceptibility Factor for Chronic Necrotizing Pulmonary Aspergillosis

It was investigated whether a deficiency of mannose-binding lectin (MBL), which binds Aspergillus species avidly in vitro, could account for chronic necrotizing pulmonary aspergillosis (CNPA), which is seen most commonly in nonimmunocompromised patients. Blood samples were obtained from 11 patients (10 white) with CNPA and were compared with blood samples from 82 white control subjects. MBL haplotype profiles were determined by polymerase chain reaction, using sequence-specific primers and sequence-specific oligonucleotide probing techniques. Seven of the 10 white patients with CNPA had MBL haplotypes that encode for low levels of the protein, compared with 25.6% of the white control subjects (P=.004). Presence of the codon 52 mutation was particularly common in patients with CNPA (P=.015), which suggests a greater involvement of this mutation.

Anti-PLA2R antibodies measured by ELISA predict long-term outcome in a prevalent population of patients with idiopathic membranous nephropathy

Antibodies to the phospholipase A2 receptor 1 (PLA2R1) have been reported in 70% of cases of idiopathic membranous nephropathy (IMN). The genetic susceptibility of IMN has been accounted for by HLA DQA1 and PLA2R1 genes. Here we retrospectively quantified PLA2R antibodies by ELISA, and genotyped DQ alleles and PLA2R1 single-nucleotide polymorphisms for association with clinical criteria for disease activity at the time of first sample and with outcome over a median total follow-up of 90 months. In 90 prevalent patients with biopsy-proven IMN, anti-PLA2R antibodies were present in 75% of patients with IMN with active disease and were significantly higher than in patients in partial or complete remission at the time of antibody measurement. There was a differential IgG subclass response (4>2>3>1) at an early stage, i.e., within 6 months of biopsy. Levels of PLA2R antibodies were significantly linked to DQA1*05:01 and DQB1*02:01. Survival analysis of patients with IMN showed that PLA2R antibodies are significantly linked with outcome. Thus, high levels of PLA2R antibodies are linked with active disease and a higher risk of declining renal function during follow-up. Future therapeutic trials in IMN should monitor anti-PLA2R, as patients with a high antibody burden may benefit from earlier therapeutic intervention.

HLA Typing and Its Influence on Organ Transplantation

Human leukocyte antigen (HLA) molecules are expressed on almost all nucleated cells, and they are the major molecules that initiate graft rejection. There are three classical loci at HLA class I: HLA-A, -B, and -Cw, and five loci at class II: HLA-DR, -DQ, -DP, -DM, and -DO. The system is highly polymorphic, there being many alleles at each individual locus. Three methods for HLA typing are described in this chapter, including serological methods and the molecular techniques of sequence-specific priming (SSP) and sequence-specific oligonucleotide probing (SSOP). The influence of HLA matching on solid organ and bone marrow transplantation is also described. HLA matching has had the greatest clinical impact in kidney and bone marrow transplantation, where efforts are made to match at the HLA-A, -B, and -DR loci. In heart and lung transplantation, although studies have shown it would be an advantage to match especially at the DR locus, practical considerations (ischemic times, availability of donors, clinical need of recipients) make this less of a consideration. Corneal grafts are not usually influenced by HLA matching, unless being transplanted into a vascularized (or inflamed) bed.

Association of symptomatic acute human parvovirus B19 infection with human leukocyte antigen class I and II alleles.

To determine the effect of the major histocompatibility complex on the development of symptoms during acute human parvovirus B19 infection, we compared human leukocyte antigen (HLA) class I and II alleles in 36 patients with symptomatic acute B19 infection with those in >900 control subjects from northwestern England. The frequency of each of HLA-DRB1*01 (P=.016), DRB1*04 (P=.007), and DRB1*07 (P<.0001) alleles was significantly higher in parvovirus B19 patients than in control subjects. In the parvovirus group, 63.9% carried the rheumatoid arthritis-associated shared epitope sequence, compared with 45% of control subjects (odds ratio [OR], 2.2; 95% confidence interval [CI], 0.97-4.8; P=.04), and carriage was associated with fatigue during the acute phase (OR, 4.2; 95% CI, 0.8-23.9; P=.047). All symptomatic parvovirus-associated HLA-DRB1 molecules carry a neutrally charged glutamine at position 10 and a positively charged lysine at position 12 of the first hypervariable region. HLA-B49 was associated with parvovirus infection independently of HLA-DRB1*01, DRB1*04, and DRB1*07.

Definitions of histocompatibility typing terms

Histocompatibility testing for stem cell and solid organ transplantation has become increasingly complex as newly discovered HLA alleles are described. HLA typing assignments reported by laboratories are used by physicians and donor registries for matching donors and recipients. To communicate effectively, a common language for histocompatibility terms should be established. In early 2010, representatives from Clinical, Registry, and Histocompatibility organizations joined together as the Harmonization of Histocompatibility Typing Terms Working Group to define a consensual language for laboratories, physicians, and registries to communicate histocompatibility typing information. The Working Group defined terms for HLA typing resolution, HLA matching, and a format for reporting HLA assignments. In addition, definitions of verification typing and extended typing were addressed. The original draft of the Definitions of Histocompatibility Typing Terms was disseminated to colleagues from each organization to gain feedback and create a collaborative document. Commentary gathered during this 90-day review period were discussed and implemented for preparation of this report. Histocompatibility testing continues to evolve; thus, the definitions agreed on today probably will require refinement and perhaps additional terminology in the future.

Definitions of histocompatibility typing terms: Harmonization of Histocompatibility Typing Terms Working Group.

Histocompatibility testing for stem cell and solid organ transplantation has become increasingly complex as newly discovered human leukocyte antigen (HLA) alleles are described. HLA typing assignments reported by laboratories are used by physicians and donor registries for matching donors and recipients. To communicate effectively, a common language for histocompatibility terms should be established. In early 2010, representatives from clinical, registry, and histocompatibility organizations joined together as the Harmonization of Histocompatibility Typing Terms Working Group to define a consensual language for laboratories, physicians and registries to communicate histocompatibility typing information. The Working Group defined terms for HLA typing resolution, HLA matching and a format for reporting HLA assignments. In addition, definitions of verification typing and extended typing were addressed. The original draft of the Definitions of Histocompatibility Typing Terms was disseminated to colleagues from each organization to gain feedback and create a collaborative document. Commentary gathered during this 90-day review period were discussed and implemented for preparation of this report. Histocompatibility testing continues to evolve thus, the definitions agreed upon today, likely will require refinement and perhaps additional terminology in the future.

Pharmacogenetic testing in the United Kingdom genetics and immunogenetics laboratories

AIM For certain drugs, pharmacogenetic tests can reduce adverse drug reactions and improve treatment efficacy. However, the adoption of pharmacogenetics into clinical practice has been relatively slow. One potential barrier is the capacity of laboratories to meet the demands of a clinical pharmacogenetic service. We aimed to establish the range, capacity to deliver, and demand for germline pharmacogenetic testing in the United Kingdom and Ireland, through an e-survey of 34 molecular genetics and 28 histocompatibility and immunogenetics (H&I) laboratories. RESULTS Thirty-five percent of molecular genetics laboratories and 54% of H&I laboratories responded to the survey. The majority of H&I laboratories (93%) offered pharmacogenetic testing, whereas only one molecular genetics laboratory provided a pharmacogenetic service. HLA-B*5701 was most commonly tested to identify those at risk of abacavir hypersensitivity among patients with HIV. A number of barriers to testing were identified, including lack of clinician knowledge and a lack of scientific evidence. All molecular genetics laboratories believed that national coordination of clinical pharmacogenetic services was required, whereas only 50% of H&I laboratories supported this view. CONCLUSIONS In the United Kingdom, pharmacogenetic testing is currently being predominantly provided through H&I laboratories for a limited number of indications. The number of laboratories offering pharmacogenetic tests is increasing and is likely to continue to increase over the coming years.

BSHI Guideline: HLA matching and donor selection for haematopoietic progenitor cell transplantation

A review of the British Society for Histocompatibility and Immunogenetics (BSHI) “Guideline for selection and HLA matching of related, adult unrelated donors and umbilical cord units for haematopoietic progenitor cell transplantation” was undertaken by a BSHI appointed writing committee. Literature searches were performed, and the data extracted were presented as recommendations according to the GRADE nomenclature.

Donor cell leukemia following unrelated donor bone marrow transplantation for primary granulocytic sarcoma of the small intestine

Granulocytic sarcoma (GS) in the absence of bone marrow involvement at diagnosis is unusual. Treatment of primary (aleukemic) GS should follow intensive acute myeloid leukemia (AML)-style chemotherapy protocols, as patients otherwise appear destined to rapidly declare frank medullary disease. However, the role of hematopoietic stem cell transplantation (HSCT) is less clear. Here we present an unusual case of isolated primary GS involving small bowel treated with chemotherapy consolidated by HSCT from an unrelated donor. Full donor chimerism was achieved and maintained, without relapse of the original disease. However, 28 months post-transplant our patient developed a distinct and rapidly progressive medullary AML, apparently derived from transplanted cells of donor origin. Donor cell leukemia (DCL) is a fascinating and increasingly recognized phenomenon, with at least 50 cases reported to date. Our case adds to this growing literature and highlights the ethical dilemmas concerning notification of unrelated donors in such cases, since there is little evidence that they are at increased risk of developing leukemia themselves. This also represents the first case of DCL reported after transplantation for primary GS.

A study of HLA-DPB1 phenotypes reveals DPB1*6301 in a rural population from Cameroon

Several recently reported HLA-DPB1 alleles have only been identified in a single family or individuals and are of unknown distribution world-wide. Many new DPB1 alleles appear to arise as a result of gene conversion-like events, which may localize variant DPB1 alleles to the population in which they were first identified. Using two SSOP-based typing methods in parallel, we have identified HLA-DPB1*6301 in an individual from rural Cameroon which has previously only been reported in a family of Mexican-American origin. The presence of DPB1*6301 was confirmed by sequence-based typing of exon 2.