HLA-DR antigens have polymorphic light chains and invariant heavy chains as assessed by lysine-containing tryptic peptide analysis.

HLA-DR antigens were isolated from B lymphoblastoid cells labeled with either [3H]- or [14C]lysine. Double-label comparisons of the tryptic peptides by microbore ion-exchange chromatography led to the following conclusions: The heavy and light chains share few peptides, one of which is free lysine that is liberated from the polypeptide chains by trypsin. The heavy chains of different HLA-DR allospecificities are virtually identical in all cell lines examined. In contrast, the light chains of different HLA-DR allospecificities are nonidentical and, thus, must bear the alloantigenic determinant.

Increased incidence of Mycoplasma pneumoniae infections detected by laboratory-based surveillance in Denmark in 2010.

In Denmark recurrent epidemics of Mycoplasma pneumoniae infections have been described since the 1950s at intervals of approximately four to six years. The latest epidemic occurred in 2004/05 followed by two years of high incidence and more than three years of low incidence. Due to a recent increase in diagnosed cases since late summer 2010, we conducted a survey of positive M. pneumoniae PCR tests performed by clinical microbiology departments in Denmark, which indicated that a new epidemic may be underway.

Genetic Diversity of Prunus necrotic ringspot virus Isolates Within a Cherry Orchard in New York.

A survey for Prunus necrotic ringspot virus (PNRSV) in an orchard of Prunus cerasus cv. Montmorency and Prunus avium cv. Hedelfingen in New York by enzyme-linked immunosorbent assay indicated an eightfold higher infection rate in sour cherry (33%, 32 of 96) than in sweet cherry (4%, 6 of 136) trees. The presence of PNRSV was confirmed by reverse transcription-polymerase chain reaction and amplification of the coat protein (CP) gene in total RNA from infected leaf tissue. Latent infection was prevalent in the majority of trees infected (87%, 33 of 38), while a few of them exhibited shock symptoms or had severely reduced growth (13%, 5 of 38). Asymptomatic PNRSV-infected trees clustered in spatial proximity to symptomatic trees. Sequence analysis of the CP gene (675 bp) indicated a population structure consisting of one predominant molecular variant for 10 isolates and six minor molecular variants for seven isolates. A high sequence identity was found between the CP gene of PNRSV isolates from cherry trees and other isolates from diverse hosts and various geographic origins at the nucleotide and amino acid levels (88 to 100%). Phylogenetic analyses showed a clustering of PNRSV isolates from cherry trees in New York in the predominant group PV-96.

Positive autologous crossmatches and a successful transplant with an HLA-identical, but not with an HLA-nonidentical, kidney.

A kidney graft from an HLA-nonidentical donor following a positive crossmatch in the presence of autoantibodies was rejected, but a subsequent graft from an HLA-A, B, C, DR-identical donor, also following a positive crossmatch, survives. Cytotoxic reactivity was present at 4 C and 37 C, and required complement. Sucrose gradient fractionation showed that most of the reactivity resided in the IgM fraction of the serum. Reactivity with donor T and B lymphocytes was not removed by absorption with platelets. Absorption with autologous lymphocytes failed to remove reactivity to lymphocytes of the first (non-HLA-identical) donor and T and B cells of another individual with the same HLA type as the first donor, although removing reactivity to T, but not to B cells of the second (HLA-identical) donor. This case demonstrates that the presence of a multitude of cold-reactive and warm-reactive T and B cell autoantibodies and non-HLA alloantibodies creates an immunological environment in which only the optimally matched graft will survive.

A complication of prolonged urokinase infusion into a chronically occluded aortocoronary saphenous vein graft.

Recanalization of a chronically occluded aortocoronary saphenous vein graft was performed, using a prolonged intracoronary infusion of urokinase followed by percutaneous transluminal coronary angioplasty (PTCA). Despite an angiographically successful result, the patient developed acute myocardial infarction, presumably secondary to distal migration of partially lysed thrombus. One week after successful angioplasty, the graft was once again proximally occluded.

Steady-state fluctuation and variability of betaxolol and atenolol plasma levels.

Twenty-four nonsmoking male volunteers took 50 mg atenolol or 10 mg betaxolol orally once a day for 9 days in a two-period, four-sequence, randomized, crossover study. Plasma concentrations reached steady state after day 5. Percent fluctuation in plasma concentration defined as (Cmax-Cmin)/Cavg (% fluctuation 1) was 97% on day 9 for betaxolol and 343% for atenolol; thus atenolol fluctuation was more than threefold that of betaxolol. A 10-fold difference in plasma level fluctuation was observed when fluctuation was defined as (Cmax-Cmin)/Cmin (% fluctuation 2). The intersubject variances for % fluctuation 1 and % fluctuation 2 were 4.1 and 85.5 times greater for atenolol than for betaxolol; these differences were marginally statistically significant for % fluctuation 1 and significant for % fluctuation 2. The intrasubject variabilities for area under the curve and plasma level fluctuations were statistically greater for atenolol than for betaxolol. Atenolol intrasubject variances were 25 and 271 times greater than for betaxolol for % fluctuation 1 and % fluctuation 2, respectively. Thus, betaxolol exhibited less fluctuation in plasma levels with substantially less intersubject and intrasubject variability. These factors would be expected to provide a more consistent therapeutic response and more dependable dosage adjustment.

Pumonary aspergillosis during hospital renovation.

During a 4-week period, Aspergillus fumigatus caused disease in 2 patients and colonized a third patient in a renal transplant ward. Our investigation indicated that increased exposure of these patients to spores probably occurred during renovation of the ward one floor above it. Cases were significantly clustered (P = 0.014) during the period when work overhead caused dust to filter down through pores in the acoustical tiles of the false ceiling of the renal transplant ward. Swab cultures demonstrated A. fumigatus in the dust, and air samples showed heavy contamination with A. fumigatus and other fungi at and below a renovation site, but not on 2 distant wards. We concluded that dust can be an important source of aspergilli and that release of dust and spores during activities such as renovation may increase the risk of nosocomial Aspergillus infection in exposed, immunosuppressed patients.

Factors responsible for successful HLA-DR typing of mononuclear cells from cord blood.

Of 115 cord blood samples tested, both HLA-DR antigens were identified in 79% of fresh samples, 66% of older samples and 55% of freshly frozen samples. Because of weak reactions, one or two questionable antigens were present in 21% of fresh samples as compared to 34% of older samples and 45% of freshly frozen samples. Older samples showed lower cell viability, more extra reactions, and a high frequency of weak reactions. Comparison of cord blood DR antigens with parental DR antigens revealed that antigens were missed or inappropriately assigned in 5 known cases. This was more frequent with older blood samples. The critical factors in successful DR typing of cord blood samples were 1) dilution of cord blood samples with medium, 2) processing of the samples as soon as possible, and 3) overnight incubation to remove adherent cells.