Clinical manifestations of human parvovirus B19 in adults.

Human parvovirus B19 has been associated with various clinical effects in a number of uncontrolled reports. To define the usual manifestations of B19 infection in adults and the factors that influence them we present a clinicoepidemiological study of an outbreak of B19 infection centered on a junior school. Four hundred fifty-three of 475 adults in this community were interviewed and blood was obtained for serological diagnosis. Fifty-four cases of recent infection were identified and were HLA typed. Fourteen of the cases were asymptomatic; 32 had an influenzalike illness; 23 a rash; and 26 an acute-onset polyarthropathy that was more common in women and lasted for up to 7 months. HLA-A, -B, and -C antigen frequencies were similar to a local control population and showed no association with symptoms except that HLA-DR1 was absent in those with persistent arthropathy.

Allogenotypes defined by short DQ alpha and DQ beta cDNA probes correlate with and define splits of HLA-DQ serological specificities.

HLA-DR and -DQ serotyped cell lines and peripheral blood leucocytes were analysed by Southern blot allogenotyping. Using a short DQ beta cDNA probe, a DQ beta allelic series was defined by restriction fragment length polymorphism (RFLP) with the restriction endonuclease TaqI. This DQ beta allelic series correlates with, and defines splits of, the HLA-DQ serological specificities DQw1 (DQ beta 1a and DQ beta 1b RFLPs), DQw2 (DQ beta 2a and DQ beta 2b RFLPs) and DQw3 (DQ beta 3a and DQ beta 3b RFLPs). By sequential use of a short DQ alpha cDNA probe a second, DQ alpha allelic series is defined by RFLP. This series correlates to a lesser extent than DQ beta RFLPs with the HLA-DQ serological specificities. Thus, two DQ alpha RFLPs correlate with a single DQ serotype (DQ alpha 1a and DQ alpha 1c with DQw1), but three DQ alpha RFLPs correlate with more than one DQ serotype (DQ alpha 1b with DQw1 and DQw3; DQ alpha 2 with DQw2 and DQw3; DQ alpha 3 with DQw2 and DQw3). Individual DQ beta and DQ alpha RFLP subtypes appear to correlate with single, or associated HLA-DR specificities. Specific combinations of DQ beta with DQ alpha RFLPs also correlate with HLA-Dw splits of DR2 and DRw6. A system for HLA-DNA typing is described, which uses RFLP patterns generated by sequential hybridization of TaqI-digested DNAs with short DR beta, DQ beta and DQ alpha cDNA probes. The DQ beta and DQ alpha probes not only identify the DQ allele, but because of linkage disequilibrium with DR, help to assign the DR allele, which may not always be identified with a DR beta probe alone.

Some methodological studies on effector cells in the lymphocyte-dependent cytotoxic antibody assay.

A method of direct freezing was found to be reliable for storage of the effectors for the LDA assay, though there is a considerable loss of cells. In order to get immunologically active K cells after thawing, an important step is to leave the cells to recuperate overnight in an appropriate medium before use. A short-term storage of fresh effectors is also possible. The use of a pool of effector cells from a minimum of 3 random blood donors obviates the selection of HL-A types furthermore permits a saving of the amount of serum used. Enrichment of a B cell population by removing the cells capable of forming spontaneous rosettes with SRBC was not found to enhance cytotoxicity. Pretreatment of cells with pronase, trypsin and neuraminidase did not significantly enhance their effector activity, while papain treated cells showed a systematically increased specific lysis.

Substantial benefits of tissue matching in renal transplantation.

The purpose of this study was to perform a rigorous statistical analysis of the benefits of HLA-A,B and DR matching in renal transplantation. Graft survival in 2282 first cadaver kidney transplants, recorded and followed up by the United Kingdom Transplant Service (UKTS), was analyzed using the piecewise proportional hazards regression method. The results show that substantial improvements in graft survival are obtained when there is DR compatibility and at most one A or B mismatch, but that there is little advantage in tissue matching unless this degree of matching can be attained. So far, few graft recipients have benefited substantially through tissue matching (24% of kidneys exchanged through UKTS in 1984). This is partly attributable to unresolved technical problems in DR typing. However simulations show that under ideal conditions, with a pool of 3000 patients awaiting transplantation, considerable improvements in graft survival can be obtained in over 60% of recipients.

Matching for properdin factor B (Bf) in renal transplantation.

Forty-five donor and recipient primary cadaveric kidney transplant pairs were phenotyped for the properdin factor B (Bf) polymorphism. Graft survival was analyzed on the basis of Bf matching between donor and recipient. Patients receiving a Bf-identical kidney had significantly better graft survival than those receiving a Bf-incompatible kidney (P = 0.045). It is postulated that Bf, which maps in the major histocompatibility system, is a marker for genes of importance in kidney transplant survival.

A DNA-RFLP typing system that positively identifies serologically well-defined and ill-defined HLA-DR and DQ alleles, including DRw10.

A single enzyme/multiple probe system of HLA-DR and DQ typing using restriction fragment-length polymorphism (RFLP) analysis is presented. TaqI-digested genomic DNAs are hybridized sequentially with short DR beta, DQ beta, and DQ alpha cDNA probes. The DR beta probe discriminates between the DR allelic specificities DR1 to DRw14, with the two exceptions of some DR3/DRw13 and some DR7/DRw9 combinations. We describe the positive identification of a DRw10-specific RFLP and demonstrate its segregation in families. The DQ beta probe defines an allelic system that identifies the alleles DQw1, DQw2, and DQw3. This permits the resolution of DR3/DRw13 and DR7/DRw9 alleles by defining the DR/DQ association caused by linkage disequilibrium. The DQ alpha probe defines another allelic series interrelated with, but independent from, the DQ beta series. Specific DQ beta/DQ alpha RFLP combinations correlate with known Dw splits of DR2, DRw6, and DR7. Combined use of the three probes permits the identification of HLA-DR, DQ, and certain Dw specificities and provides an effective and easily interpretable system for major histocompatibility complex class II allogenotyping.

The origin of HLA-DR"Br": exon 2 nucleotide sequence implicates possible gene conversion of DR1 by DR4-Dw10, DR5, or DRw6-Dw18.

The exon 2 nucleotide sequences of HLA-DQwl-associated and DQw3-associated HLA-DR"Br" alleles were determined from genomic DNA amplified by the Taq polymerase chain reaction technique. Both alleles reveal identical exon 2 nucleotide sequences. Comparison with other DR alleles suggests that DR"Br" may have originated from DR1 by gene conversion with DR4-Dw10, DR5, or DRw6-Dw18 third hypervariable region sequences.

Molecular characterization of a recombinant HLA-DR1/DR2 haplotype.

Serologic analysis of two families identified an HLA-DR haplotype in which DR1 and DR2 cosegregated. DNA-RFLP analysis of these families with an HLA-DRB probe revealed a pattern of hybridization suggestive of a recombination between DR1 and DR15. Following amplification, cloning, and nucleotide sequencing of HLA-DRB-gene second-exon DNA sequences, three DRB amplification products associated with the novel haplotype were identified: these corresponded to DRB1*0101, DR2 pseudogene, and DRB5*0101. Clones representing the DRB1*1501 and DR1 pseudogenes were not identified: oligonucleotide typing with DRB1*1501-specific probes confirmed the absence of this gene within the DR1/DR2 haplotype. We postulate that the DR1/DR2 haplotype represents a recombinant between those of DR1-Dw1 and DR15-Dw2, and that the crossing-over may have been between the DRB1*0101 gene and the DR2 pseudogene. This is further supported by DNA-RFLP analysis with HLA-DQB and DQA CDNA probes, which revealed conserved linkage genes between the DQB1*0501, DQA1*0101, and DRB1*0101 genes.

HLA DQ alpha and DQ beta restriction fragment length polymorphisms associated with Felty's syndrome and DR4-positive rheumatoid arthritis.

HLA DQ alpha and DQ beta cDNA probes were used to study TaqI generated restriction fragment length polymorphisms (RFLPs) in DR4-positive patients with Felty's syndrome (FS), seropositive rheumatoid arthritis (RA), and in HLA-DR4 positive controls. The results of this analysis revealed two DQ beta RFLP patterns (DQ beta 3a and DQ beta 3b) associated with DR4, of which DQ beta 3b was found at significantly higher frequency in patients with FS (73%) or with RA (52%) than in DR4 controls (29%). Hind III generated RFLPs provide evidence that DQ beta 3b is in strong linkage disequilibrium with the gene encoding the serologically recognized epitope TA10. Results obtained using a DQ alpha chain probe revealed polymorphic differences between DQ alpha chain genes associated with different DR types, thereby providing a possible explanation for the lack of association between RA and other DR haplotypes in linkage disequilibrium with TA10. We conclude that both DQ alpha and DQ beta genes may be important in determining HLA-linked susceptibility to severe forms of RA.

A possible haplotype association in Felty's syndrome.

The HLA-B7/DR association was examined in a normal British population and in seven HLA-B7-positive patients with Felty's syndrome. After the exclusion of the most frequent A3-B7-DR2 association, a significant A2-B7-DR4 association was evident. This was present in six of the seven HLA-B7-positive Felty's patients and might indicate that the A2-B7-DR4 haplotype is prevalent in some forms of rheumatoid arthritis.

Restriction fragment length polymorphism in Felty's syndrome.

Southern blot analysis with DR beta and DQ beta cDNA probes was used to compare genomic DNA from Felty's syndrome patients with HLA-DR-matched normal controls. We describe two restriction fragment length polymorphisms putatively associated with Felty's syndrome.

Association between keratoconus and atopy.

Sixty-seven patients with keratoconus were classified according to atopic status. Keratoconus patients with and without atopy did not differ significantly with regard to sex, age of onset, or rate of keratoplasty, but patients with very high IgE levels were more prone to graft rejection. Atopy was less common in patients with unilateral keratoconus, and keratoconus occurred more frequently on the side of the dominant hand. There was a significantly lower frequency of HLA B7 in the keratoconus group than in the controls. No abnormalities of essential fatty acid metabolism were found in keratoconus patients with or without atopy. There was no social class bias in the group. The study included a brother and sister with keratoconus and atopy, and a non-atopic patient whose identical twin did not have keratoconus.