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Biomedical subjects

R H McLean

Publications and source records attributed to R H McLean.

At least 55 records · Page 3Linked to original sources
PubMed1986

Idiopathic linear glomerular IgA deposition.

Linear deposition of IgA immunoglobulin was found along the glomerular basement membrane in two patients with normal renal function and no pulmonary abnormalities. One patient had recurrent gross hematuria and a mild focal proliferative glomerulonephritis without deposits on electron microscopy; the second patient had a renal cell carcinoma. This observation of linear IgA antibody deposition in the absence of Goodpasture's syndrome or diabetes mellitus extends the spectrum of diseases associated with glomerular basement membrane-IgA deposition.

Adolescent↗
PubMed1985

Null alleles of the fourth component of complement and HLA haplotypes in familial systemic lupus erythematosus.

Eight families (121 individuals) with two or more members affected with systemic lupus erythematosus (SLE) were analyzed for histocompatibility antigens (HLA-A, B, C, DR, MT, and MB) and complement antigens (C4A, C4B, and BF). These data were correlated with serological markers (antinuclear antibodies, single- and double-stranded anti-DNA, anti-SM, anti-nRNP, anti-Ro [SS-A], anti-La [SS-B], and biological false-positive tests for syphilis and clinical features. Fifteen members had SLE, and 19 had other immune diseases (subacute cutaneous lupus erythematosus, discoid lupus erythematosus, hypothyroidism, insulin-dependent diabetes mellitus, primary Sjogren's syndrome, immune thrombocytopenic purpura, rheumatoid arthritis, and multiple sclerosis). Twenty-three healthy relatives (seroreactors) had significant titers of circulating antibodies, as did 2 of 17 spouses. There was an increased frequency of null C4 alleles in those individuals with SLE (60%) and healthy relatives (50%) as compared with spouses (24%). Multivariate analysis showed a significant association between SLE and female sex (P =.006), whereas there was no significant association revealed between female sex and other immune diseases. Patients with SLE also had a higher frequency of either C4A or C4B null alleles (P = .01) than those with immune diseases. The C4A homozygous null phenotype was more common in SLE patients than in seroreactors (P = .02). There was a higher frequency of HLA-DR2 and DR3 in individuals with SLE than in those with immune disease (P = .08), seroreactors (P = .02) and normal relatives (P = .002). One totally C4-deficient patient with SLE was identified. These families demonstrate an important association between SLE and the C4 null allele and the HLA-DR2 and DR3. These risk factors, however, cannot account for the development of disease in all individuals.

Adult↗
PubMed1985

Hypomorphic variant of the slow allele of C3 associated with hypocomplementemia and hematuria.

This report describes the first instance of a hypomorphic variant (C3*s) of the most common C3 allele, C3 Slow, which was detected in a four-year-old Caucasian boy with hematuria. Analysis of C3 phenotypes, as determined by agarose electrophoresis, showed a hypomorphic C3 Slow in the patient and a maternal aunt. Serum C3 concentration was significantly reduced in the patient and his mother (610 and 750 micrograms/ml; normal +/- 1 SD = 1,240 +/- 240 micrograms/ml) and was at the lower limits of normal in the affected aunt (770 micrograms/ml). The mother's phenotype was C3 S (? Ss) and she was the presumed carrier, since the father (C3 FS) had neither an abnormal C3 S band nor a low C3 concentration (980 micrograms/ml). Total hemolytic complement was significantly reduced only in the patient (19 units/ml; normal = 38 +/- 16). Hypomorphic C3 variants should be considered in the evaluation of decreased serum C3 levels.

Alleles↗
PubMed1984

Complement phenotypes in glomerulonephritis: increased frequency of homozygous null C4 phenotypes in IgA nephropathy and Henoch-Schönlein purpura.

Polymorphism of three complement genes (C4A, C4B, and BF) located within the major histocompatibility complex was studied in 48 biopsy-proven IgA nephropathy patients and nineteen patients with Henoch-Schönlein purpura (HSP). Polymorphism was determined by immunoelectrophoretic techniques and functional activity using an overlay of sheep cells in agarose and C4 deficient sera. The subjects were divided into four large groups according to the presence or absence of a C4 null allele (a gene producing no identifiable gene product): group 1 (no null variants), group 2 (one C4A null variant), group 3 (one C4B null variant), and group 4 (two null variants at either the C4A or C4B locus, that is, homozygous null). Patients had a significantly increased frequency of group 4 phenotypes (homozygous null): (12 of 67 patients, 17.8%) as compared to controls (4 of 102 patients, 3.9%, P = 0.0031). Both IgA (P = 0.045) and HSP patients (P = 0.003) had a greater frequency of a C4 homozygous null phenotype. The serum C4 concentration was higher in patients than in controls (740 mg/ml and 576 micrograms/ml, respectively, P = less than 0.001) whether evaluated together or by C4 phenotypic group. The association between the presence of IgA nephropathy or HSP with a homozygous C4 null phenotype is of unknown significance but suggests a predisposition to development of HSP or IgA nephropathy for individuals with the C4 homozygous null phenotype.

Chromosome Mapping↗
PubMed1984

Mesangial proliferative glomerulonephritis with IgM deposits. Clinicopathologic analysis and evidence for morphologic transitions.

To determine the natural history of mesangial proliferative glomerulonephritis (MesPGN) with IgM deposits and its relationship to minimal change disease (MC) and focal segmental glomerulosclerosis (FGS), we studied the clinical characteristics and outcome in 20 patients with MesPGN, 8 with MC, and 10 with FGS. IgM deposits were present in glomeruli of all MesPGN patients. Progression to FGS was documented in 2 patients with MesPGN, 1 of whom developed renal failure. Transition from MC to MesPGN occurred in 1 patient. 2 MC patients developed FGS, with decline in renal function in 1 of them. These data suggest the possibility of histologic transition from MC to FGS directly or through the stage of MesPGN.

Adolescent↗
PubMed1983

Selective complete Clq deficiency associated with systemic lupus erythematosus.

We report a case of systemic lupus erythematosus (SLE) and recurrent infections associated with isolated Clq deficiency. A 17-year-old girl from Saudi Arabia was hospitalized with seizures, fever, arthralgia, hair loss, oral ulceration and skin rash. Clinical and laboratory findings fulfilled the ARA preliminary criteria for the classification of SLE. Nonlesional skin contained immunoglobulins and C3 at the dermal-epidermal junction. She did not have antibodies to DNA or low C3 or C4. Total serum hemolytic complement activity was absent due to a total selective absence of Clq. There was no circulating inhibitor of Clq activity. The published experience of isolated selective complete Clq deficiency associated with clinical disease is reviewed.

Adolescent↗
PubMed1982

Partial H (beta 1H) deficiency and glomerulonephritis in two families.

H (beta 1H) controls the C3b amplification loop by its ability to displace Bb from the alternative pathway convertase, C3b,Bb, and acts as a cofactor with I (C3b inactivator) to produce inactive C3b. Serum C3 levels are dependent to a large extent on the levels of H and I. Partial H deficiency was found in two families. The index case in Family 1 had vasculitis, thrombocytopenia, proteinuria, and depressed serum H and C3 levels. The index case in Family 2 had depressed serum H and B (Factor B) levels and IgA nephropathy which progressed to renal failure. His sister also had IgA nephropathy and depressed serum H and C3 levels. The depressed serum C3 level, B level, and H level could be responsible for the development of the immune diseases found in some members of these families.

Adolescent↗
PubMed1982

Serum hemolytic factor D values in children with steroid-responsive idiopathic nephrotic syndrome.

Serum hemolytic factor D activity, an important component of the ACP, was measured in patients with SR-INS. The mean serum factor D hemolytic activity of patients with SR-INS in relapse was significantly reduced compared to the mean of the control group. Twenty-one of 27 SR-INS patients in relapse (78%) had reduced serum factor D activity. In contrast, the mean serum factor D hemolytic activity of SR-INS patients in remission was not significantly different from that in the control group. Factor D hemolytic activity was also reduced in other types of renal disease with the nephrotic syndrome. Serum factor D values were highly correlated with the serum albumin concentration. Although hemolytic factor D activity could not be detected in the urine, the low molecular weight and the significant correlation with serum albumin concentration suggest that urinary loss is responsible for the low serum levels of factor D. Deficient serum values of factor D may contribute to the increased susceptibility of SR-INS patients in relapse to bacterial infections with organisms which activate the ACP.

Adolescent↗
PubMed1981

Meningococcal meningitis in familial deficiency of the fifth component of complement.

Absence of the fifth component of complement (C5) by immunochemical assay and marked deficiency by hemolytic assay (less than 0.1%) was found in a family in which the oldest male child had suffered severe and recurrent meningococcemia at age 15 years, two brothers developed meningococcal meningitis four years later (at ages 18 and 14 years), and a sister had the gonococcal arthritis-dermatitis syndrome. Although group-specific meningococcal antibody was present in the sera from all four siblings, serum bactericidal activity against Neisseria meningitidis could be demonstrated only in the presence of exogenous rabbit complement. Serum total hemolytic complement activity was undetectable in all four, but was restored to normal by the addition of purified C5. Subsequently, a second episode of group Y meningococcal meningitis was experienced by one brother and presumed gonococcal arthritis-dermatitis syndrome recurred in the sister. The family is the largest C5-deficient kindred to be reported and emphasizes the importance of C5 in host susceptibility to invasive Neisseria infections. In contrast to the peak incidence of N meningitidis disease in the general population in the first year of life, age of onset of meningococcal infection in these patients and in the 13 previously reported patients with terminal complement component deficiency has usually been in adolescence and early adulthood.

Adolescent↗
PubMed1980

Renal venous thrombosis in neonates. Initial and follow-up abnormalities.

Five neonates with renal venous thrombosis (RVT) were studied at the onset of the disease, and four have been followed up for from 24 to 32 months after the time of diagnosis. Reduced glomerular filtration (two of four cases) on follow-up occurred only in infants with bilateral abnormalities as shown by results of physical examination, urography, renal scan, and angiography. Results of contrast studies showed the similarity between resolved RVT and certain congenital renal abnormalities. Renal tubular defects (polyuria, acidosis, hyperkalemia) constituted the primary clinical abnormalities in one of the two infants with renal insufficiency. Although the prognosis of RVT after medical management has improved, the ultimate outcome is unknown; the possibility of unsuspected neonatal RVT should be considered during investigation of children with unilaterally or bilaterally small kidneys.

Child, Preschool↗
PubMed1980

Familial discoid lupus erythematosus associated with heterozygote C2 deficiency.

Two siblings with chronic discoid lupus erythematosus and several family members were found with heterozygous C2 deficiency. An association with histocompatibility markers HLA-B18 and HLA-Dw2 was demonstrated, and the slow allotype of factor B was present. Linkage studies in this family suggested a close linkage between the C2 deficiency gene and genes coding for B18, Dw2, and BfS antigens. One HLA-ACB/DBf recombinant was observed showing closer linkage between HLA-D and Bf than between HLA-B and Bf.

Adolescent↗
PubMed1980

Familial partial deficiency of the third component of complement (C3) and the hypocomplementemic cutaneous vasculitis syndrome.

Familial hypocomplementemia of the third component of complement (C3) was found in four members of a family. The prospositus had cutaneous vasculitis, hypocomplementemia, arthralgia, proteinuria and thrombocytopenia. The combination of clinical, laboratory and pathologic findings resembled the "hypocomplementemic cutaneous vasculitis syndrome" (HCVS) or the "SLE-like syndrome" but serum C3 concentration was 35 to 57 per cent of normal in the propositus and in three relatives. Results of Clq precipitins, cryoglobulins and serologic tests for systemic lupus erythematosus were negative. Proteinuria (815 mg/day) but no hematuria was present. Analysis of the C3 phenotypes in this family showed that three hypocomplementemic members were apparent homozygous C3 slow but one was heterozygous C3 fast-slow. Metabolic studies with 125-Iodinated C3 in the clinically normal mother showed a 50 per cent reduction in C3 synthesis which was consistent with hypocomplementemia documented by serum protein assay. The occurrence of an immune complex-like disease (with characteristics of the HCVS) in a patient with a familial deficiency of C3 suggests that the preexisting C3 deficiency may predispose such persons to certain diseases.

Adolescent↗