Serum Complement C3 Levels Research Articles

Immunopathogenesis of Takayasu arteritis.

Takayasu arteritis is a common cause of renovascular hypertension in India. Sensitization to infective agents, particularly mycobacterium tuberculosis or autoimmune disturbances have been incriminated in its pathogenesis. Twenty patients of Takayasu arteritis along with groups of normal individuals, patients of essential hypertension, autoimmune disorders, tuberculosis, and healthy tuberculin reactors were studied. Besides detailed immunological profiles including LE cell phenomenon, serum complement C3 levels, antibodies to single (SS) and double stranded (DS) DNA, rheumatoid factor, lymphocyte subsets, blast transformation to antigens including, phytohemagglutinin, PPD, pokeweed, and purified human aortal antigen (PHAA) were examined. Soluble protein from human aorta was fractionated into 9 peaks by DEASE-52 and Sephadex G-75 chromatography, and 25 micrograms of major protein fraction-II was used for blast transformation study. Blast transformation by PHAA was higher in Takayasu arteritis as compared to all other groups (P < 0.05). Blast transformation to PPD showed wide variation in all the groups, and was significantly higher only in tuberculin reactors as compared to controls. These observations support aortal sensitization to PHAA playing a role in pathogenesis of Takayasu arteritis and do not relate tuberculosis to Takayasu arteritis, at least immunologically. In addition, the ratio of CD-4 positive to CD-8 positive lymphocytes changing in favor of the former and the concomitant increase in B lymphocytes favor the presence of autoimmune disturbances in Takayasu arteritis.

Effect of vitamin A in enteral formulae for burned guinea-pigs

A burned guinea-pig model (30 per cent body surface area) was used to study the effects of dietary vitamin A. Sixty-five female guinea-pigs were infused enterally via gastrostomy feeding tubes with identical formulae (175 kcal/kg/day, 20 per cent of calories as protein) containing varying amounts of vitamin A. Groups I, II, III and IV received formulae containing 0, 10 000iu (approximately equivalent to the guinea-pigs' RDA), 50 000 iu (5 x RDA) and 250 000 iu (25 x RDA) of vitamin A per litre, respectively. After 14 days of tube feeding, the animals were killed. Group I animals had evidence of vitamin A deficiency including low haemoglobin levels, lower red blood cell counts and lower caecal mucosal weight. Findings of hypervitaminosis A were observed only in animals given the highest dose of vitamin A (25 × RDA). These were elevated serum alkaline phosphatase and complement C3 levels and enlarged adrenal glands. Group IV also showed defective cell-mediated immunity as reflected by reduced delayed cutaneous response to dinitrofluorobenzene. In a second experiment groups I, II, III and IV were given formulas containing 0,1 × RDA, 5 × RDA, and 10 × RDA of vitamin A respectively for 14 days. Through postburn days 12 to 14 they were injected subcutaneously with 3 × 10 8 of Staphylococcus aureus once daily. On postburn day 15 the animals were killed and the numbers of viable bacteria at each injection site were counted. No significant differences were observed in viable bacterial numbers between the groups. Serum vitamin A concentration was significantly lower in group I, and there was no sign of hypervitaminosis A in the other groups. These findings suggest that vitamin A is needed following burn injury, and doses of I RDA to 10 RDA may be administered safely. However, overdosage (25 × RDA) may be quite harmful.

Immunological studies in sickle cell disease: Comparison of homozygote mild and severe variants

Cellular and humoral immune functions in patients suffering from severe and mild forms of homozygous sickle cell disease (SCD) were compared with those of healthy control subjects. Random neutrophil migration, chemotactic activity, and lymphocyte transformation index were all defective in individuals with severe variants of SCD when compared with individuals with mild disease or healthy controls. In contrast, serum opsonization activity was significantly reduced in both severe and mild variants of SCD. There were no statistical differences between serum immunoglobulin (IgA, IgG, and IgM) or complement C3 levels in any of the three groups. These results demonstrate that even though individuals with the mild variant of SCD possess two S genes, their immune functions are generally normal and in parallel with their clinical and hematological status. The one area of impaired immune function is their defective serum opsonization activity and this may explain their sensitivity to certain infections.

Immunodiagnosis of autoimmune skin disease in the dog, cat and horse.

Skin biopsies from 47 dogs, 6 cats and 5 horses with suspected autoimmune skin disease were submitted for immunofluorescence from 1978 to 1985. These cases were predominantly Western Australian in origin, although a number were also referred from Queensland and Victoria. In 5 dogs, 2 cats and 2 horses immunoglobulin binding to intercellular cement substance and/or basement membrane was demonstrated by direct immunofluorescence. Antinuclear antibody was also demonstrated in several of these cases. Immunofluorescence was used in combination with histopathological examination to confirm the clinical diagnosis of autoimmune disease in 19/47 dogs, 4/6 cats and 2/5 horses. There was no age, breed or sex predisposition amongst the 19 positive dogs, however there was a higher incidence of antinuclear antibody (54%) than the normal canine population (10%) and other autoantibodies (rheumatoid factor) were sometimes present. Abnormalities in serum protein electrophoresis and serum complement C4 levels were also recorded in this group.

Mechanisms of Schistosoma mansoni egg excretion: parasitological observations in immunosuppressed mice reconstituted with immune serum.

Summary CBA mice which had been deprived of their T cells by a combination of adult thymectomy and injection of rabbit anti‐mouse thymocyte serum failed to excrete as many Schistosoma mansoni eggs in their faeces as immunologically intact controls. This failure of parasite egg excretion was not obviously attributable to any marked change in the amount of faecal matter produced, or to a change in the size of the worm burden, or to the number or distribution of eggs in the tissues as a result of T‐cell deprivation. S. mansoni eggs freshly isolated from T‐cell‐deprived mice and injected intravenously into normal animals, induced lung granulomas which were the same size as those induced by injection of eggs from normal donors. The rate of S. mansoni egg excretion was not affected by the density of eggs in the tissues, in as much as there was a linear relationship between the number of tissue‐bound eggs and the number of eggs detected in the faeces. Treatment of infected mice with the immunosuppressant hydrocortisone acetate also induced a marked reduction in the rate of egg excretion. Injections of serum derived from chronically infected normal mouse donors increased the rate of egg excretion in both T‐cell‐deprived and steroid‐treated mice, but the degree of reconstitution obtained by daily serum injections was only partial relative to normal egg excretion rates. Treatment of infected normal or deprived serum‐treated mice with cobra venom factor to reduce serum complement C3 levels had no effect on the rate of S. mansoni egg excretion.

Serum immunoglobulin, complement C3, and salivary IgA levels in lead workers

Sera of 72 lead workers and of 53 reference subjects were examined for levels of immunoglobulins IgM, IgG, and IgA, and complement C3 by radial immunodiffusion. Salivary IgA levels were determined in 33 lead workers and 40 reference subjects. On the average the lead workers had lower serum complement C3 and immunoglobulin levels, as well as lower salivary IgA levels, than the reference subjects. A significant negative correlation was found between blood lead concentrations (PbB) and the serum levels of complement C3 and IgG in the group of lead workers, as well as in the total population examined. However, a significant positive correlation was observed between PbB and serum IgA in the group of lead workers. The results obtained in this study are discussed in relation to numerous reports in the literature showing that lead exerts adverse effects on the immune system in animals.

Immunological studies in cows' milk protein-sensitive enteropathy.

55 infants, aged between 1 and 13 months, who presented with persistent diarrhoea were placed on a diet free of cows9 milk protein. The clinical condition of the infants improved and 6-8 weeks later each was challenged with low-lactose cows9 milk. The following investigations were performed before and 24 hours after provocation: jejunal biopsy, serum and duodenal juice levels of complement C3 and C4, C3-activator, and immunoglobulins A, G, M, and D. Three groups were recognised on postchallenge clinical symptoms together with histological changes in the jejunal mucosa: group 1 (n=10 infants) with no clinical or mucosal abnormality, group 2 (n=18 infants) with mucosal abnormalities but lacking clinical symptoms, and group 3 (n=27 infants) with mucosal abnormalities and clinical symptoms; but in group 3 symptoms were delayed for over 24 hours in 7 infants, and in the remaining 20 infants symptoms appeared within 24 hours. After provocation the serum IgG levels were decreased in 3 infants in group 1, 12 in group 2, and 17 in group 3. The mean serum IgA and IgM levels were higher in group 1 compared with group 2 or 3; pre- and postchallenge mean serum immunoglobulin levels, complement, and complement activator levels were of equal magnitude in all three groups. A depletion of serum complement C3 level was observed in 4 (group 1), 4 (group 2), and 13 (group 3) infants 24 hours after provocation with cows9 milk; the fall in serum IgG was often associated with depletion of complement in serum. This suggests the involvement in some infants of IgG-mediated complement-consuming immune reactions in the development of the damage in the intestinal mucosa. After challenge, exudation of IgG and IgA occurred irrespective of the presence or absence of mucosal damage and was not always associated with the decrease in serum IgG concentration. Because of the variable conditions present in the intestinal lumen it is suggested that the level of immunoglobulins in duodenal juice is not a reliable measure of the local immune response. Levels of complement and immunoglobulin in serum or duodenal juice fail to provide help in the diagnosis of cows9 milk protein-sensitive enteropathy.

The Significance of Serial Measurement of Serum Anti-Native DNA Antibodies and Complement C3 and C4 Components in the Management of Patients with Systemic Lupus Erythematosus

Serial measurements were made over a period of three years of serum DNA-binding capacity and complement C3 and C4 levels in parallel with documentation of clinical features of disease activity in Glasgow patients with SLE. Raised DNA-binding levels were noted in 27 of the 32 patients over this time period. High levels (over 80%) were found in patients with both renal and non-renal disease. In some patients increases in DNA-binding capacity and decreases in C3 levels were associated with changes in disease activity. This pattern was commonest in patients with renal SLE. In others DNA-binding capacity was elevated without any relationship to SLE disease activity. A fall in serum C3 levels was usually significant while serum C4 levels frequently fell without any change in clinical features of disease activity. Very low serum C4 levels (below 15 mg/dl), however, were usually of clinical relevance. The uses of immunological measurements in the differential diagnosis of a major illness in a patient with SLE are discussed. The finding of such an illness in a patient with normal serum DNA-binding levels made it unlikely that the illness was due to an exacerbation of the SLE and more likely that an alternative cause such as supervening bacteraemia was responsible.