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A girl and her mother were diagnosed as having membranoproliferative glomerulonephritis (MPGN) type I. Microscopic hematuria and proteinuria presented at 9 years of age in the mother and at 14 years in the daughter. Both had persistent hypocomplementemia and were treated with steroids. When the mother was 40 years old, proteinuria was still continuing and creatinine clearance was 64.4 ml/min per 1.73 m(2). When the daughter was 15 years old, microscopic hematuria was still continuing. To our knowledge, familial cases of MPGN in two generations have not been reported in Japan.

Urinary and cerebrospinal fluid (CSF) levels of 8-hydroxydeoxyguanosine (8-OHdG) were examined to estimate the relevance of oxidative stress in children with brain damage. Urinary 8-OHdG levels were measured in 51 children with various forms of central nervous system (CNS) disorders (status epilepticus [SE], hypoxic-ischemic encephalopathy [HIE], CNS infections and chronic epilepsy) and these levels were compared with those in 51 healthy children. CSF 8-OHdG levels were measured in 25 children with brain damage and in 19 control subjects. In addition, urinary and CSF levels of 8-OHdG were compared between the children with brain damage and healthy children. Finally, the relationship between urinary and CSF levels of 8-OHdG was determined in 12 children that provided both urinary and CSF samples. Our results showed that urinary 8-OHdG levels in children with HIE and CNS infections were higher than those of controls (Steel test; p0.05 and p0.05, respectively) and that CSF 8-OHdG levels were higher in children with SE, HIE, and CNS infections than in control subjects (Steel test; p0.01, 0.05 and 0.05, respectively). In addition, a positive correlation between the levels of urinary and CSF 8-OHdG was noted in the 12 children that provided both CSF and urinary samples (Spearman's rank correlation; rho = 0.82, p0.01). Further, we observed changes in the urinary 8-OHdG in a patient with HHV-6 encephalopathy, and found that the changes correlated well with the patient's clinical condition. These results suggest that oxidative stress is strongly related to acute brain damage in children, and that 8-OHdG is a useful marker of brain damage. Therefore, repeated measurements of urinary 8-OHdG may be helpful in estimating the extent of brain damage.

The prevalence of undermasculinized external genitalia has increased in several countries including Japan, and this phenomenon has primarily been ascribed to the deleterious effects of environmental endocrine disruptors such as dioxins. To examine a possible role of the genetic susceptibility to dioxins in the development of micropenis (MP), we studied the Arg554Lys polymorphism of the gene for aryl hydrocarbon receptor (AHR) and the Pro185Ala polymorphism of the gene for aryl hydrocarbon receptor repressor (AHRR), in 73 boys with MP (34 boys with mild MP from -2.1 to -2.5 SD and 39 boys with severe MP below -2.5 SD) and 80 control males (50 boys and 30 fertile adult males). The allele and genotype frequencies of the AHR polymorphism were comparable between the two groups of males, but those of the AHRR polymorphism were significantly different, with the Pro allele and the Pro/Pro genotype being more frequent in boys with MP than in control males (P-value: 0.0029 for the allele frequency and 0.011 for the genotype frequency). In addition, both polymorphisms were comparable in the allele and genotype frequencies between boys with mild MP and those with severe MP and between control boys and control fertile adult males. The results suggest that the AHRR Pro185Ala polymorphism may constitute a susceptibility locus for the development of MP in response to dioxins.

A retrospective investigation was conducted by members of the Japanese Society for Pediatric Nephrology from 1990 to 1997 to define the clinical features and outcomes in children with antineutrophil cytoplasmic autoantibody (ANCA)-positive glomerulonephritis associated with propylthiouracil treatment. Seven Japanese pediatric patients who had myeloperoxidase-specific ANCA-positive biopsy-proven pauci-immune necrotizing crescentic glomerulonephritis associated with propylthiouracil administration were entered in the study. Three patients had nephritis alone, and four had nephritis and extrarenal organ system vasculitis. Females predominated, and the mean age at onset was 14 yr. Propylthiouracil was reduced or discontinued in all patients and was switched to methimazole in three patients. For the treatment of nephritis, five patients received corticosteroids; three had pulse methylprednisolone, one had plasma exchange, and one had plasma exchange and pulse methylprednisolone before initiating oral prednisolone. The remaining two patients received cyclophosphamide and corticosteroids, one of whom had pulse methylprednisolone before initiating oral prednisolone and cyclophosphamide. All patients achieved remission. In general, ANCA titers correlated with the response to treatment and disease activity, with some exceptions. No patient progressed to end-stage renal disease, renal dysfunction, or death during the follow-up period (58 +/- 25 mo; range, 32 to 108 mo). All but one patient remained euthyroid. In conclusion, this experience suggests that the clinical disease spectrum of ANCA-positive disease associated with propylthiouracil treatment is similar in pediatric and adult patients and that the overall prognosis may be better than that in the non-drug-induced ANCA-positive disease.

We report a case of myositis ossificans progressiva in Japan. The patient was 7 yearsold who had swelling and pain of his back and arms. He had surgically treated for halluces valgus of his left foot when he was 2 years old. Laboratory examination on admission of our hospital showed elevated serum phosphate and calcium. On plain roentogenogram, ectopic ossification of bilateral biceps muscles was noted. Chest computed tomography showed severe deformity and constriction of his thorax, and the ectopic ossification was confirmed. Magnetic resonance imaging of his back and neck revealed massive swelling of his muscles including left sternocleidomastoid muscle. Muscle biopsy has not been performed, because his diagnosis of having myositis ossificans progressiva is definitive, and histological examination of the specimen has been reported to have difficulty on differential diagnosis of myositis ossif icans progressiva from other types of malignancies of muscle origin including soft tissue sarcoma and inflammatory myositis. In addition, muscle injury caused by the biposy procedure accelerates progression of the disease including inflammation and ossification. There is no clear cut explanation of the pathophysiology of nor effective treatment of the disease. We need to accumulate and experience more patients with the same disease to elucidate their pathophysiology and to carry out the genetic linkage study of this disease in Japan.

We investigated the effects of dexamethasone on nitric oxide synthase activity, nitrate/nitrite concentration, and cGMP concentration in the lungs of premature and full-term neonate rats. Dexamethasone or vehicle alone was administered to the mother (1 mg/kg/d, s.c., 2 d), and the neonate was killed 24 h after birth. Ca2+-dependent nitric oxide synthase activity and nitrate/nitrite and cGMP concentrations in lungs of dexamethasone-treated neonates, both premature and full-term, were significantly higher than those in the lungs of the control rats. Ca2+-dependent nitric oxide synthase activity, nitrate/nitrite concentration, and cGMP concentration in the lungs of control rats showed developmentally associated increases during late gestation and in the early postnatal period. The activation of the nitric oxide synthasenitric oxide-cGMP system by antenatal dexamethasone treatment may be related to the improvement of pulmonary function by antenatal glucocorticoid therapy to minimize respiratory distress syndrome.

We investigated the developmental changes in the pattern of urinary metabolites of theophylline, a substrate for CYP1A2, to study when CYP1A2, which is absent in the perinatal period, fully develops during childhood. The urinary ratios of three metabolites (1-methyluric acid, 3-methylxanthine, and 1,3-dimethyluric acid) to theophylline in patients over 3 y of age show a much larger interindividual variation compared with those under 3 y of age, and the mean values of the ratios in patients over 3 y of age were greater than those in patients under 1 y of age. The urinary ratio of 1,3-dimethyluric acid (a metabolite generated by several cytochrome P450s) to 3-methylxanthine or 1-methyluric acid (metabolites generated by CYP1A2 exclusively) seemed to be relatively constant over 3 y of age; in patients under 3 y of age, these ratios were much higher than those in patients over 3 y of age. The urinary ratio of 1-methyluric acid to 3-methylxanthine or 3-methylxanthine to 1-methyluric acid seemed to be relatively invariable in all patients except those less than 1 y of age. These findings suggest that CYP1A2 activity may be programmed to mature by around 3 y of age and that CYP1A2 probably plays a major role in theophylline 8-hydroxylation at a therapeutic concentration after the full development of CYP1A2 activity.

The most appropriate treatment for patients with IgA nephropathy is controversial. Treatment with prednisolone, azathioprine, heparin-warfarin, and dipyridamole early in the course of disease may prevent immunologic renal injury in children with severe IgA nephropathy. To determine whether similar results can be obtained with a combination of just heparin-warfarin and dipyridamole, the effects of such treatment were compared to those of treatment with prednisolone, azathioprine, heparin-warfarin, and dipyridamole in 78 children with newly diagnosed IgA nephropathy showing diffuse mesangial proliferation. The patients were randomly assigned to receive either prednisolone, azathioprine, heparin-warfarin, and dipyridamole for 2 yr (group 1) or heparin-warfarin and dipyridamole for 2 yr (group 2). All of the 40 patients in group 1 and 34 of the 38 patients in group 2 completed the trial. The mean urinary protein excretion fell in group 1 patients (P < 0.0001), but remained unchanged in group 2 patients. The mean serum IgA concentration was reduced in group 1 patients (P = 0.0002), but was unchanged in group 2 patients. BP and creatinine clearance were normal at the end of the trial in all but one group 2 patient, who developed chronic renal insufficiency. The percentage of glomeruli showing sclerosis was unchanged in group 1 patients, but increased in group 2 patients (P = 0.006). The intensity of mesangial IgA deposits decreased in group 1 patients (P = 0.02), but remained unchanged in group 2 patients. In conclusion, the present study shows that treatment of children with severe IgA nephropathy with prednisolone, azathioprine, heparin-warfarin, and dipyridamole for 2 yr early in the course of disease reduces immunologic renal injury and prevents increase of sclerosed glomeruli.

気管支喘息の治療に使用されるテオフィリン (TP) は一定量での持続静脈内投与にもかかわらず症例によっては血中濃度が低下することが報告されている。しかし, その機序は明らかではない。そこで喘息発作にて入院後TPの持続投与を行った患児に, 投与開始後3日間の血中濃度と尿中代謝物を測定し, 血中濃度低下と薬物代謝能との関連について検討した。対象となった35例は, TP血中濃度不変群20例と血中濃度が10%以上低下した低下群15例に分かれた。血中濃度低下群では, 測定した3つの尿中代謝物比のうち, DMU/TPに有意な変動は認めなかったが, 3MX/TP, 1MU/TPは有意に増加した。不変群ではいずれの代謝物比にも有意な変動を認めなかった。以上, 喘息患児においておよそ40%の症例で持続投与にもかかわらず, 3MXと1MUへの代謝亢進によって生じたと考えられるTP血中濃度の低下を認めた。このような症例では, 治療開始後の血中濃度低下に留意し投与計画を決定する必要がある。

Mutations in the COL4A5 gene in Alport syndrome: A possible mutation in primordial germ cells. Using a combination of gene amplification with single strand conformation polymorphisms analysis and sequencing, we examined the COL4A5 gene in 37 patients with Alport syndrome. In patient A8, a single base insertion was noted at codon 1,597 tyrosine in exon 49. The premature terminal signal appeared and 89 amino acids (approximately one-third) of the non-collagenous domain were lost. The mutation was present in the mother, hence she is heterozygous. In patient A12, the nucleotide changed from C to T at codon 1,679 glutamine in exon 51, which created a termination codon, and 7 amino acids at the carboxyl terminus were lost. Gene tracking using peripheral leukocytes revealed that the parents did not carry the mutant allele, while the sister was heterozygous. DNA samples from hair roots and skin fibroblasts of the mother were normal and immunological examination of the epidermis of the mother indicated that the α5(IV) chain was normally expressed. As these results suggest that somatic cells of the mother do not carry the mutant allele, the primordial germ cells possibly carry a fresh mutation in the mother of patient A12.

The efficacy of KRN8601 for neutropenia associated with HIV infection was evaluated in 24 patients. KRN8601 was infused intravenously at a dosage of 200 micrograms/m2 for 14 consecutive days. Neutrophil counts recovered in 19 (90.5%) out of 21 evaluable patients by KRN8601 treatment. The concomitant myelosuppressive agents for the treatment of HIV infection and complications could be continued without dose reduction in 15 (88.2%) out of 17 patients. The clinical improvement was observed in 66.7% (12/18) of patients who were treated with anti-microbial agents for opportunistic infections which indicates that KRN8601 shows an additive effect on infections when it was given with anti-microbial agents. Adverse events and abnormal laboratory findings were observed in 3 and 7 patients, respectively, and they were reversible and tolerable. This study demonstrated that KRN8601 improved neutropenia with HIV infection, made possible to continue the full dose of myelosuppressive treatments and have additive effect on the treatment of secondary infections.

Identification of a single base insertion in the COL4A5 gene in Alport syndrome. We identified a novel mutation in the COL4A5 gene of a Japanese patient with Alport syndrome. A combination of in vitro amplification of the exons with single strand conformation polymorphisms (SSCP) analysis suggested the presence of a mutation in exon 48. Sequencing of the amplified DNA revealed a single base (T) insertion which was between nucleotides T 4750 and G 4751 within the methionine 1516. This mutation caused a shift in the reading frame of nine amino acids and introduced a premature termination signal that would be expected to lack about two-thirds of the noncollagenous (NCI) domain. This mutation may interfere with type IV collagen assembly leading to increased permeability and play a causative role in the glomerular basement membrane abnormality of this patient with typical Alport syndrome. Gene tracking by restriction enzyme NlaIII digestion revealed that the patient's mother is heterozygous whereas the patient's brother and one sister are normal, albeit they have hematuria and proteinuria. Without gene analysis, they would have been misdiagnosed. We propose that the diagnosis of Alport syndrome should be made on the basis of both clinical phenotypes and molecular defects.

The slit diaphragm connecting the adjacent foot processes of glomerular epithelial cells (podocytes) is the final barrier of the glomerular capillary wall and serves to prevent proteinuria. Podocytes are understood to be terminally differentiated cells and share some common features with neurons. Neurexin is a presynaptic adhesion molecule that plays a role in synaptic differentiation. Although neurexin has been understood to be specifically expressed in neuronal tissues, we found that neurexin was expressed in several organs. Several forms of splice variants of neurexin-1α were detected in the cerebrum, but only one form of neurexin-1α was detected in glomeruli. Immunohistochemical study showed that neurexin restrictedly expressed in the podocytes in kidneys. Dual-labeling analyses showed that neurexin was colocalized with CD2AP, an intracellular component of the slit diaphragm. Immunoprecipitation assay using glomerular lysate showed that neurexin interacted with CD2AP and CASK. These observations indicated that neurexin localized at the slit diaphragm area. The staining intensity of neurexin in podocytes was clearly lowered, and their staining pattern shifted to a more discontinuous patchy pattern in the disease models showing severe proteinuria. The expression and localization of neurexin in these models altered more clearly and rapidly than that of other slit diaphragm components. We propose that neurexin is available as an early diagnostic marker to detect podocyte injury. Neurexin coincided with nephrin, a key molecule of the slit diaphragm detected in a presumptive podocyte of the developing glomeruli and in the glomeruli for which the slit diaphragm is repairing injury. These observations suggest that neurexin is involved in the formation of the slit diaphragm and the maintenance of its function.

We investigated the effects of prenatal dexamethasone (DEX) administration on antioxidant enzymes (AOEs) and nitric oxide synthase (NOS) in fetal and neonatal rat lungs. DEX (1 mg/kg, s.c., for 2 days) or vehicle alone was administered to pregnant rats, and the lungs of fetuses on days 19 and 21 of gestation and of 1- and 3-day-old neonates were examined. We measured protein levels of the AOEs manganese superoxide dismutase and copper-zinc super-oxide dismutase (Mn SOD and Cu-Zn SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and inducible and endothelial nitric oxide synthase (i-NOS and e-NOS). Mn SOD, GSH-Px, and e-NOS expression gradually increased with increasing gestational and postnatal age in the lungs of the control groups. Cu-Zn SOD, CAT, and i-NOS expression did not change with increasing gestational and postnatal age in the lungs of the control groups. DEX administration had significant effects on i-NOS and e-NOS protein and mRNA expression. The increased Mn SOD, GSH-Px, and e-NOS expressions during the perinatal period suggests that antenatal developmental changes in AOEs in the lungs of premature fetuses could be reduced by reactive oxygen species–mediated injury at birth. Furthermore, antenatal glucocorticoid treatment may accelerate the development of lungs via the two types of NOS. Keywords:: reactive oxygen species, antioxidant enzyme, dexamethasone, superoxide dismutase, nitric oxide synthase

In order to investigate the participation of monocytes/macrophages(Mo/M phi) in the progression of various kidney diseases of children, Mo/M phi in urine and that infiltrating renal tissue were both measured as the number of CD68 positive Mo/M phi (CD68+ Mo/M phi), using anti-CD68 antibody. The number of CD68+ Mo/M phi infiltrating in one glomerulus was significantly higher in Henoch-Schönlein purpura nephritis(HSPN) (p0.01) in comparison with that in minimal change nephrotic syndrome(MCNS) (p0.01), and a high tendency was found in IgA nephropathy (IgAN), proliferative glomerulonephritis (non-IgAN), focal segmental glomerulosclerosis(FSGS) and membranoproliferative glomerulonephritis (MPGN), respectively. The number of CD68+ Mo/M phi infiltrating one mm2 of tubulo-interstitium area was significantly higher in HSPN(p0.05), FSGS(p0.01), Alport's syndrome(p0.01), respectively, than that in MCNS. The number of CD68+ Mo/M phi in one milliliter of urine correlated significantly with both that infiltrating the glomerulus and the tubulo-interstitium(both p0.01). Moreover the number of urine CD68+ Mo/M phi in a clinically active stage was significantly higher than that in an inactive stage in the AGN(p0.05), IgAN(p0.05), HSPN(p0.05), non-IgAN(p0.01) and MPGN groups(p0.05), respectively. From these results, 1) It was suggested that the Mo/M phi infiltrating renal tissue participated in the development of various kidney diseases. 2) It was predicted that CD68+ Mo/M phi in urine reflected both the number of Mo/M phi infiltrating the glomerulus and that in the tubulo-interstitium. 3) It was suggested that the number of CD68+ Mo/M phi in urine indicated clinical activity in proliferative glomerulonephritis groups of children.

Aretrospective investigation was conducted by members of the Japanese Society for Pediatric Nephrology from 1990 to 1997 to define the clinical features and outcome of antineutrophil cytoplasmic autoantibody (ANCA)-associated glomerulonephritis in children. Thirty-four ANCA-seropositive Japanese pediatric patients with biopsy-proven pauci-immune necrotizing crescentic glomerulonephritis were identified. Of these, 3 cases associated with Wegener's granulomatosis were excluded because of the small sample size. Among the 31 patients studied, 10 had a diagnosis of necrotizing crescentic glomerulonephritis alone and 21 had microscopic polyangiitis. Females predominated (87%), and the median age at onset was 12 yr. Twenty-six patients received treatment with cyclophosphamide and corticosteroids, and five patients received treatment with corticosteroids alone; 84% of patients achieved remission, and 39% of responders relapsed in a median of 24 mo. ANCA titers correlated with response to treatment and disease activity, with some exceptions. Patients were followed for a median of 42 mo (range, 3 to 96 mo). Nine of 31 patients (29.0%) progressed to end-stage renal disease, 6 (19.4%) had reduced renal function, and 15 (48.4%) had normal renal function at the last observation. One patient (3.2%) died from cytomegalovirus infection 3 mo after initiation of therapy. Life-table analysis showed 75% renal survival at 39 mo. Patients who subsequently developed end-stage renal disease (n = 9) had significantly higher average peak serum creatinine levels and more chronic pathologic lesions at diagnosis compared with patients with favorable renal outcome (n = 15). In conclusion, our clinical experience suggests that the clinical disease spectrum of ANCA-associated glomerulonephritis is similar in pediatric and adult patients, but there is a female predominance in children.

The authors investigated whether theophylline metabolism is decreased in asthmatic patients and what condition may be related to its reduction. Fifty-two children with asthma were given 15 mg/kg/day aminophylline intravenously at a constant rate. Blood and spot urine samples were collected at 24 hours, 48 hours, and 72 hours after beginning infusion. The ratio of plasma theophylline concentration at 72 hours to that at 24 hours (C72h/C24h) varied from 0.42 to 1.51 (average 0.894). Plasma theophylline concentration of patients with lower C72h/C24h than average reduced significantly, while the concentration of those with higher C72h/C24h remained unchanged. The urinary ratio of the sum of the metabolites to theophylline was significantly increased in the patients with the lower ratio. Among the demographic characteristics examined, significant difference was found only in the incidence of patients with C-reactive protein (CRP) of 0.5 mg/dl or greater or patients with a fever of 37.5 degrees C or greater when admitted. Acute febrile illness accompanied by increased CRP level may affect theophylline metabolism.

A paediatric case of lipoprotein glomerulopathy, a new kidney disease characterized by glomerular lipoprotein thrombi, is reported. The patient had massive proteinuria from the age of 8 years, when the nephrotic syndrome was first detected. This was resistant to conventional treatment for more than 10 years. During the course of the disease, the hyperlipidaemia characteristic of hyper-pre-beta-lipoproteinaemia and elevation of apoprotein E persisted, and renal function gradually deteriorated. The renal histopathological findings from four biopsies were essentially the same, with storage of beta-lipoprotein in dilated, balloon-like glomerular capillary lumina. However, the number of glomeruli showing global sclerosis increased and tubulo-interstitial changes progressed in parallel with the gradual clinical deterioration. As in other cases reported in Japan some familial involvement has been noted.

Neither the hemolytic activity nor the protein level of the seventh component of serum complement (C7) was detectable in an 8-year-old girl with nephritis, but in her parents and her brother, they were about half of the normal level. The patient was a homozygote type with a complete deficiency of C7 while her parents and brother were all heterozygote type with a partial deficiency of C7. C7-consuming activity was demonstrated in the native serum of the patient with complete C7 deficiency, and it was found that large amounts of C56 were readily generated upon incubation of the patient's serum with zymosan. It is proposed that the C7-consuming activity in the native serum of this patient is due to small amounts of C56 generated during the activation of serum complement by some kind of infection such as a common cold.

Serum complement level in 77 patients with Graves' disease was periodically measured before and after various treatments including antithyroid drug administration and surgical operation. The complement titers showed remarkable fluctuation during the preoperative periods. However, the average complement titers in patients with this disease were not significantly different from those in patients with other thyroid diseases and in healthy volunteers. In patients whose clinical signs improved after surgical operation, the fluctuation of complement titers became smaller, falling within a normal range. To examine the possible local activation of complement system in thyroid glands of Graves' disease, immunofluorescent stainings were performed in 30 thyroid glands with this disease utilizing fluorescein isothiocyanate (FITC)-labeled antisera against immunoglobulins and complement components. Granular deposition of IgG, IgA, IgE, Clq, C3, and C9 was observed along the follicular basement membrane (FBM) and/or at the stroma. IgG deposits along the FBM were usually accompanied with Clq, C3, and C9 deposition. None of 12 IgG-positive glands were stained by FITC-labeled antiserum to fibrinogen. Seven normal glands showed no significant staining for any of those immunoglobulins and complement components. These observations indicate that complement system may be locally activated in the thyroid gland via the classical pathway and that deposition of soluble immune complexes may occur in the FBM of Graves' disease. Such local activation of complement may be in part the cause of strong fluctuation of complement levels in hyperthyroidism patients.

IgA nephropathy in patients with congenital C9 deficiency. The clinical, histologic, and immunopathological findings of three young Japanese males with congenital C9 deficiency and primary IgA nephropathy are reported. The C9 deficiency was discovered either through mass complement screening, or when low hemolytic activity for CH50 and normal C3 levels were detected in plasma. Hematuria and proteinuria were detected at the age of 8 or 9 years as a result of annual urinary screening tests for school children. Renal biopsy showed focal and segmental mesangial proliferation with small epithelial crescents in one patient, and mild, diffuse mesangial proliferation in two. IgA and C3 were deposited predominantly in the mesangial area, and staining for C9 was negative in these patients. Electron microscopy revealed electron dense deposits predominantly in mesangial and paramesangial zones. Immunohistochemical staining in renal biopsy tissues from two patients showed mesangial staining for C5, C8, and S-protein, but staining for C5b-9 neoantigen was completely negative. These results show that the formation of C5b-9 complex is not essential for the induction of human IgA nephropathy, and also for the proliferation of mesangial and even parietal epithelial cells.

An inhibitory activity against neutrophil chemotactic factors was found in normal human serum. Elevated levels of this chemotaxis inhibitory activity were demonstrated in sera of patients with systemic lupus erythematosus (SLE). The physico-chemical characteristics of this chemotaxis inhibitory substance(s) in SLE serum were almost identical to those of the inhibitory substance(s) in normal human serum; both the inhibitory substances were heat labile, soluble in 45% saturated ammonium sulphate, worked directly on chemotactic factor and affected various chemotactic factors. A study using Sephadex G- 100 chromatography showed that the molecular sizes of both inhibitory substances were almost identical. No correlation was found between the levels of the chemotaxis inhibitory activity in SLE sera and other clinical parameters including erythrocyte sedimentation rate, and serum concentration of either the third component of complement (C3) or the fourth component of complement (C4). Specimens from patients with the following diseases failed to demonstrate elevated levels of chemotaxis inhibitory activities; rheumatoid arthritis, urticaria, psoriasis vulgaris, atopic dermatitis and discoid lupus erythematosus (DLE).