The association of respiratory infection, recurrent hematuria, and focal glomerulonephritis with activation of the complement system in the cold

Gross Hematuria Following SARS-CoV-2 Infection in IgA Nephropathy: A Report of 5 Cases

Gross hematuria after upper respiratory tract infections is a well-known characteristic symptom of immunoglobulin A nephropathy (IgAN). In recent years, there have been several reports of existing or newly diagnosed patients with IgAN susceptible to gross hematuria after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. However, reports of patients with IgAN and gross hematuria after SARS-CoV-2 infection are extremely rare despite a considerable number of patients with coronavirus disease 2019 (COVID-19) who preferentially present with upper respiratory symptoms. Here, we report the cases of 5 Japanese patients with IgAN who developed gross hematuria associated with SARS-CoV-2 infection. These patients presented with fever and other COVID-19-related symptoms, followed by the appearance of gross hematuria within 2 days, which lasted for 1-7 days. Acute kidney injury occurred after gross hematuria in 1 case. In all cases, microhematuria was identified before gross hematuria associated with SARS-CoV-2 infection, and it persisted after the gross hematuria episode. Because repeated gross hematuria and persistent microhematuria may lead to irreversible kidney injury, the clinical manifestations of patients with IgAN during the COVID-19 pandemic should be carefully monitored.

The Human Virome and Its Crosslink with Glomerulonephritis and IgA Nephropathy

The prokaryotic, viral, fungal, and parasitic microbiome exists in a highly intricate connection with the human host. In addition to eukaryotic viruses, due to the existence of various host bacteria, phages are widely spread throughout the human body. However, it is now evident that some viral community states, as opposed to others, are indicative of health and might be linked to undesirable outcomes for the human host. Members of the virome may collaborate with the human host to retain mutualistic functions in preserving human health. Evolutionary theories contend that a particular microbe's ubiquitous existence may signify a successful partnership with the host. In this Review, we present a survey of the field's work on the human virome and highlight the role of viruses in health and disease and the relationship of the virobiota with immune system control. Moreover, we will analyze virus involvement in glomerulonephritis and in IgA nephropathy, theorizing the molecular mechanisms that may be responsible for the crosslink with these renal diseases.

Title IgA Nephropathy and Oral Bacterial Species Related to Dental Caries and Periodontitis

A relationship between IgA nephropathy (IgAN) and bacterial infection has been suspected. As IgAN is a chronic disease, bacteria that could cause chronic infection in oral areas might be pathogenetic bacteria candidates. Oral bacterial species related to dental caries and periodontitis should be candidates because these bacteria are well known to be pathogenic in chronic dental disease. Recently, several reports have indicated that collagen-binding protein (cnm)-(+) Streptococcs mutans is relate to the incidence of IgAN and the progression of IgAN. Among periodontal bacteria, Treponema denticola, Porphyromonas gingivalis and Campylobacte rectus were found to be related to the incidence of IgAN. These bacteria can cause IgAN-like histological findings in animal models. While the connection between oral bacterial infection, such as infection with S. mutans and periodontal bacteria, and the incidence of IgAN remains unclear, these bacterial infections might cause aberrantly glycosylated IgA1 in nasopharynx-associated lymphoid tissue, which has been reported to cause IgA deposition in mesangial areas in glomeruli, probably through the alteration of microRNAs related to the expression of glycosylation enzymes. The roles of other factors related to the incidence and progression of IgA, such as genes and cigarette smoking, can also be explained from the perspective of the relationship between these factors and oral bacteria. This review summarizes the relationship between IgAN and oral bacteria, such as cnm-(+) S. mutans and periodontal bacteria.

Cold-dependent activation of complement: recognition, assessment, and mechanism

Cold-dependent activation of complement (CDAC) is a phenomenon characterized by low hemolytic complement activity in chilled serum. Complement component levels are normal when measured immunologically, and there is normal hemolytic activity in EDTA plasma or serum maintained at 37 degrees C. Little attention has been paid to CDAC except in Japan, and current unfamiliarity with it, even by clinical immunologists, can lead to confusion and unnecessary laboratory tests. A 66-year-old patient with a complex medical history is described whose complement tests showed abnormalities characteristic of CDAC. Evidence for classical complement pathway activation in the cold was obtained by CH50 measurements, by hemolytic C4 determinations, by C4a, C3a, and C4d generation, and by quantitating C1s-C1r-(C1 inhibitor)2 complexes. A good correlation was observed among these parameters. Cryoprecipitates were absent. CDAC activity has persisted for over 5 years and is greater at 13 than at 4 degrees C. Activation is ablated by heating at 56 degrees C and restored by the addition of C1 to the heated serum. Adsorption by streptococcal protein G-Sepharose and precipitation by 2.5% polyethylene glycol support the hypothesis that CDAC is caused by aggregated IgG. The CDAC factor(s) also induces complement activation in normal serum but has not interfered with Raji cell or C1q binding tests or with FACS analysis. More limited studies of a second individual experiencing CDAC yielded similar results.

Adverse reactions in selected patients following intravenous infusions of gamma globulin

Fifteen patients with hypogammaglobulinemia or agammaglobulinemia were treated with intravenous gamma globulin preparation over a 17-month period. The patients were selected for treatment if they had chronic antibody deficiency syndromes associated with increased susceptibility to infections. Levels of circulating immune complexes, C1q, C3, and C3d were determined in serum samples obtained before treatment and immediately following treatment with the gamma globulin. In every patient studied, circulating immune complexes were detectable in the postinfusion samples. Two patients had adverse reactions to the intravenous gamma globulin therapy. Analysis of the serum samples of both of these patients showed that one patient had an autoantibody to IgA and the other had an autoantibody to beta-lipoprotein. Both IgA and beta-lipoprotein were present in the intravenous gamma globulin preparations. Therefore, reaction with each of the autoantibodies by the antigens activated the complement system in vivo with production of split products of C3.

Surgical adjuvant therapy of malignant melanoma with corynebacterium parvum

The authors' previous surgical adjuvant trial in patients with malignant melanoma at high risk of recurrence has shown no difference in disease-free interval or survival between patients randomized to surgery + BCG or surgery alone. Reported here is a subsequent nonrandomized trial in 30 similar patients who received surgery + Corynebacterium parvum (CP) 4 mg I.V. daily x 5, followed by 4 mg S.C. weekly for up to three years. After I.V. C. parvum, chills, fever, headache, and hypertension were common. After S.C. C. parvum, varying degrees of local induration, erythema, and pain were experienced. Dose reduction was necessary for 14 patients during I.V. treatment and for six patients during S.C. treatment. A marked decrease in absolute lymphocyte count and a decreased proliferative response of lymphocytes to common antigens in vitro was observed after 2-3 days of I.V. C. parvum. Lymphocyte reactivity to mitogens decreased, particularly with Con A. Marked increase in nitroblue tetrazolium reduction by granulocytes was seen in 20 patients. Although changes in delayed cutaneous hypersensitivity reactions to recall antigens followed no consistent pattern, reactivity to DNCB increased in 18 patients. In addition, median time to recurrence was 33 weeks, significantly shorter than in the previous trial, but the survival distribution was no different from before. It can be concluded, therefore, that the administration of C. parvum in this dose and schedule had essentially no effect on the outcome of these patients.

Ultrastructural "fingerprint" in cryoprecipitate and glomerular deposits: a case report of systemic lupus erythematosus

A 20 year old woman had lupus nephritis and cryoglobulinemia. The cryoglobulins isolated from the serum and a renal biopsy specimen were studied by means of immunofluorescence, immunochemistry, and electron microscopy. Ultrastructural "fingerprint" structures were observed both in the cryoprecipitate and in the glomerular deposits, as were IgG, IgM, and IgA. These observations furnish morphologic evidence for the glomerular deposition of cryoglobulins in lupus nephritis.

Primary hepatocellular carcinoma with hepatitis B antigenemia: effects of chemotherapy

Eight patients with primary hepatocellular carcinoma (PHC) whose blood was positive for hepatitis B surface antigen (HBsAg) received treatment with cyclophosphamide, adriamycin, and 5-fluorouracil. In 4 cases, a rise in serum HBsAg titer occurred after chemotherapy. In 2 cases involving drug-related leukopenia, the rise in HBsAg titer was marked and associated with a sharp rise in the serum transaminase level (SGOT), up to 1700 in 1 case. Lower-dosage chemotherapy was safely resumed after SGOT had returned to pretreatment levels. No evidence of immunodeficiency after chemotherapy was revealed by in vitro testing of lymphocyte and granulocyte function, percentage of circulating T-cells, and immunoglobulin and complement levels. All 8 cases were negative for e antigen (eAg) and 4 were anti-positive. In 3 of 4 cases, anti-e became negative after chemotherapy, but all remained eAg negative. The negative eAg tests in these cases of PHC suggest they are not highly infectious, in spite of increased HBsAg titers in blood following chemotherapy.

Circulating immune complexes in sera of children with neuroblastoma: correlation with stage of disease

The presence of circulating immune complexes (ICS) in freshly drawn sera of 67 children with neuroblastoma was studied by the Raji cell radioimmunoassay of Theofilopoulos et al. (J. Clin. Invest. 57: 169--182), with particular emphasis on the correlation of levels of ICS with stage of disease and changes attributable to treatment. There was a close correlation between amount of complexes and stage of disease and treatment. Levels of ICS increased as the stage of the disease advanced, and were significantly higher (P less than 0.005) in stage IV than in all other stages combined. When patients with stage IV disease were subdivided into "before," "during," and "after" treatment groups, there was a significant decrease in ICS levels as treatment progressed. Studies of complement and complement components did not give such a clear relationship. A significant decrease of hemolytic C1 values was found in patients with "active disease" compared to normal age-matched controls. Some high C3 levels, determined immunochemically, were associated with low hemolytic levels of C3, which were attributed to C3 cleavage detected by immunoelectrophoresis. Based on our survival data, ICS, which were significantly different in 20 patients now decreased when compared to those of other patients, are very valuable in the prognosis of neuroblastoma.

Intralesional injection of the methanol extraction residue of Bacillus Calmette-Guerin (MER) into cutaneous metastases of malignant melanoma

Twenty-two patients with cutaneous metastases of malignant melanoma were treated with intralesional injections of the methanol extraction residue of bacillus Calmette-Guerin (MER). The local reaction consisted of erythema and pustule formation followed by ulceration and tumor necrosis. Side effects included fever, chills, headache and malaise in the majority of patients; nausea, vomiting, cyanosis and hypotension occurred infrequently. Hypersensitivity reactions were not observed. Temporary abnormalities in liver function were seen in 11 of 19 patients tested. Reversible lymphopenia and thrombocytopenia developed in 7 of 17 and 7 of 18 patients, respectively. Immune function, as measured by skin tests for delayed hypersensitivity and the in vitro response of isolated lymphocytes to mitogens and microbial antigens, was not influenced by treatment with MER. Transient increases were observed in total hemolytic complement, complement components and the reduction of nitroblue-tetrazolium by neutrophils. Eight of eighteen evaluable patients showed a complete disappearance of all injected lesions. We conclude that intratumoral injection of MER is effective treatment for cutaneous metastases of malignant melanoma, with a complete response rate comparable to that observed after intralesional injection of BCG.

Circulating immune complexes detected by 125I-Clq deviation test in sera of cancer patients

The presence of circulating immune complexes in freshly drawn sera of patients with various forms of malignancies was detected by the 125I-Clq deviation test of Sobel et al. More than 50% of the 459 cancer sera showed a high inhibition of 125I-Clq uptake by sensitized sheep erythrocytes when compared with sera of 50 healthy laboratory personnel. The levels were compared with levels of total hemolytic complement and immunochemical determinations of Cl1 and C3. A correlation between high levels of circulating immune complexes and low levels of Clq was suggested. These immune complexes were separated by sucrose density gradient ultracentrifugation at low pH and were found to be heavier than 19S. Fluctuation of levels of immune complexes was evident when serial samples from the same patient were tested. Decrease of levels of immune complexes and a concomitant increase of Clq were detected after Calmette-Gueérin bacillus and autologous tumor cell treatment in some melanoma patients.

Evidence for immune complexes involving anti-lymphocyte antibodies associated with hypocomplementaemia in chronic lymphocytic leukaemia (CLL)

Unmeasurable total haemolytic complement (C) was observed in serum of a patient with untreated chronic lymphocytic leukaemia and recurrent non-hereditary angioedema. Analysis of C components immunochemically demonstrated a marked reduction of C1q and C1s inhibitor, undetectable C1r, C1s and an elevated B. Haemolytic C1, C4 and C2 were less than 5 percent of normal, functional C1s inhibitor was absent. Cryoglobulin and C1q precipitins were present in the serum. Of special interest was the presence of high levels of cold-reactive antilymphocyte antibody, determined by both C-dependent cytotoxicity and indirect immunofluorescence. The antibody exhibited specificities for both autologous lymphocytes and lymphocytes from normal donors; cytotoxic activity for autologous leukaemia cells was removed by absorption with normal isologous tonsil lymphocytes. Specific enrichment of this antibody relative to the serum level was demonstrated in the cryoglobulin and its isolated 19S fractions. Free lymphocyte surface antigen was also demonstrated by gel diffusion using specific rabbit antilymphocyte antiserum. These data strongly suggest the presence of pathogenetically significant circulating complexes of lymphocyte surface antigen and specific antibody in certain patients with CLL.

Linkage of gene for C2 deficiency and the major histocompatibility complex MHC in man. Family study of a further case

Close linkage between HL-A and C2 deficiency was first reported by FU and co-workers in 1974. We present here a pedigree of a 31-year-old C2-deficient individual with clinical manifestations of Hodgkins disease. The following markers were tested: C2 levels, factor B polymorphism, blood groups, and enzyme typing. In addition to close linkage between HL-A and C2 deficiency, both parents were heterozygous for Bf (HL-A linked, electrophoretic variation of B). The two HL-A haplotypes closely linked to C2 deficiency are different: 2, W18 and W24, W18. They share, however, the SD2 antigen W18 and the LD type 7a.

Reversible activation of proactivator (factor B) of the alternative pathway without cleavage of the molecule

The serum of a patient (M.C.) with chronic glomerulonephritis and renal deposits of IgA, C3, and properdin converted C3 on overnight exposure of 0 degrees C. The cold reaction was dependent on immunoglobulin, initiating factor, Factors B and D, and magnesium but not on properdin. Factor B, the C3-cleaving enzyme in this reaction, was used in zymogen form. After participation in this rection, Factor B zymogen in M.C. serum could be fully activated by cobra venom factor (CVF) at 37 degrees C. That activation without fragmentation was not due to an abnormal form of Factor B was shown by its typical cleavage on incubation of MC. serum with CVF or C3b or after depletion of C3b inactivator. The evidence indicates that in the cold reaction only the initial C3 convertase of the alternative parhway is formed and that this enzyme is responsible for the observed C3 consumption.

Glomerulonephritis with mesangial deposits of IgA unassociated with systemic disease

Typical features of IgA-associated nephritis were found in renal biopsies from 16 of 355 consecutive patients. Generalized segmental mesangial proliferation was noted in biopsies from most patients, and dense deposits were detected by electron microscopy in mesangial regions of approximately 50% of biopsies. Immunofluorescent studies showed IgA to be the predominant immunoglobulin in glomueruli; IgG was present in less than 50% of biopsies and IgM in only 12%. The serum IgA value was significantly increased (P les than 0.001) in 50% of patients and the mean IgA/IgG ratio was significantly increase (P less than 0.001) for the patient group as a whole, which suggests a selective increase in IgA. Mesangial deposits of C3 were present in 15 of 16 biopsies and properdin was noted in all biopsies tested; C4 was not demonstrated in any biopsy. This suggests activation of the alternative complement pathway. The results of this study support the concept that IgA-associated nephritis is a unique condition that in some patients gives rise to idiopathic recurrent hematuria. Although the prognosis is good in the majority of patients, the renal disease may progress.

Isolated glomerulonephritis with mesangial IgA deposits

Mesangial deposits of IgA, occurring in the absence of systemic disease known to be associated with nephritis, were detected by immunofluorescence microscopy in renal biopsy specimens from 25 patients (4% of 630 specimens studied). Associated deposits of C3 were always present, usually with IgG, but IgM deposits were less common and C1q was never seen. On light microscopy most of the biopsy specimens showed mesangial of focal nuclear proliferation though some were normal. Fifteen of the 25 patients presented with macroscopic haematuria, which was usually recurrent and preceded by a sore throat, whereas the remaining, and usually older, patients presented with persistent proteinuria and were more likely to have impaired renal function. This incidence of "mesangial IgA disease" is less than that reported by French workers. There was a significantly high incidence of familial renal disease among these patients. No abnormalities of serum complement or IgA concentration were found.

The secretory immune system and renal disease

An immunopathological analysis of renal tissue from 105 patients was undertaken: (1) to clarify the relationship of the secretory immune system to renal diseases in which glomerular deposits of immunoglobulin A, (alpha chain), occurred; (2) to determine the lower nephron localization of secretory component and alpha chain in renal disease. This study, which included twenty-four patients with glomerular deposits of alpha chain, failed to reveal glomerular localization of secretory IgA. Secretory component was not found in renal tubular cells in kidneys with normal or minimally abnormal renal histology. In contradistinction to these findings, significant amounts of secretory component were found in tubular epithelial cells and casts in tissue from fifty-one patients with morphological evidence of significant renal damage; this localization had no correlation with glomerular deposits of IgA, IgM or other immunoreactants. Alpha Chain was rarely found in the tubular epithelium or in interstitial round cells; fifteen patients had alpha chain in casts. We conclude that the glomerular localization of immunoglobulin in glomerulonephritis is not derived from the secretory immune system, and the IgA present in glomeruli is not secretory IgA. The finding of secretory component in tubular cells in diseased kidneys without alpha chain may support an hypothesis for an independent role for secretory component in renal disease, apart from its function in the transport and stabilization of secretory IgA.

Activation of the complement and properdin systems in rheumatoid arthritis

The classic (C1, C4, and C2) and properdin factors (D, C3b, and B) of complement generate C3 convertases that are capable of cleaving C3 and subsequently activating C5-C9. Both C1 and factor D are serine esterases, and both convertases undergo decay and regeneration. In seropositive rheumatoid arthritis, where intraarticular activation of the classic early components (C1, C4, and C2) by immunoglobulin complexes appears to predominate, findings of relative depressions in synovial fluid levels of factor B indicate recruitment of the amplification loop (D, C3b, and B), and relative declines in properdin levels suggest activation of the properdin pathway as well. Quantitative analysis of the complement system in disease states requires several different approaches: measurement of function and antigenic concentration to assess the functional integrity of the protein; determination of component metabolism to appreciate the relative contributions of hypercatabolism and hyper- or hyposynthesis to the plasma level; and for compartmentalized disease, measurement of the component in the appropriate biologic fluid and determination of local tissue synthesis.

Proerdin and recurrent macroscopic haematuria

Kidney biopsies from ten children with recurrent macroscopic haematuria, showed mesangial deposition of IgG, IgA and complement. Eight of these ten biopsies also showed disposition of properdin, a basic euglobulin intimately involved in the alternate pathway of complement activation. Serum haemolytic complement activity was normal in the eight patients tested. Incubation of the serum at 4 degrees C for 24 dours did not result in any change in complement activity. Theses data suggest that the mesangial inflammatory process in these patients may be medicated in part by the alternate pathway of complement activation and that the mechanism is activated locally.

A serum factor in chronic hypocomplementemic hephritis distinct from immunoglobulins and activating the alternate pathway of complement

Nephritic factor (C3NeF) has been isolated from plasma of patients with hypocomplementemic chronic glomerulonephritis (HCG) by ion exchange and molecular sieve chromatography. This material was further treated with solidified anti-Ig antiserum. The purified material failed to react with antiserum to human IgG, IgG3, Fab, Fc, and kappa and lambda chains, but retained full C3NeF activity. The nonidentity of C3NeF with IgG was further demonstrated by Ouchterlony analysis using anti-IgG and anti-C3NeF. Isolated C3NeF was found to be a protein with a sedimentation coefficient of 7S and a mol wt of 150,000 daltons, which on microzone electrophoresis and gel electrophoresis at pH 8.6 behaved as a gamma-globulin. C3NeF is not a C1q precipitin and does not activate the classical complement pathway. Unlike cobra venom factor, it failed to enter into a complex with C3 proactivator (C3PA) when incubated with normal human serum (NHS) and then subjected to sucrose density gradient ultracentrifugation. The action of isolated C3NeF on C3 requires C3PA, C3PA convertase (C3PAse), and properdin (P). Similarly, C3PA conversion by C3NeF requires P, C3PAse, and C3. Total hemolytic activity was lost by incubation of 64 microg of C3NeF/1 ml NHS at 37 degrees C for 30 min. Both C3a and C5a anaphylatoxin could be generated by C3NeF in serum previously depleted of anaphylatoxin inactivator. Anti-C3NeF was found to detect an antigen in all NHS tested. Treatment of NHS with solidified anti-C3NeF caused impairment of the alternate complement pathway. It failed to sustain lysis of glutathione-treated human erythrocytes initiated by inulin. It is conceivable that the normal serum constituent which is removed by anti-C3NeF constitutes the inactive precursor of C3NeF, and a heretofore unrecognized component of the alternate pathway.