The molecular basis of hereditary complement factor I deficiency is described in two pedigrees. In one pedigree, there were two factor I-deficient siblings, one of whom was asymptomatic and the other suffered from recurrent pyogenic infections. Their factor I mRNA was analyzed by reverse transcription of fibroblast RNA followed by amplification using the polymerase chain reaction. Both siblings were homozygous for the same transversion (adenine to thymine) at nucleotide 1282 in the cDNA. This mutation causes histidine-400 to be replaced by leucine. The altered histidine is a semi-conserved residue within the serine proteinase family, although no function has been ascribed to it. The proband of the second pedigree studied was found to be a compound heterozygote. One allele had the same mutation as the first family, the second allele had a donor splice site mutation that resulted in the deletion of the mRNA encoded in the fifth exon (a low-density lipoprotein receptor domain) from its transcript. ( J. Clin. Invest. 1996. 97:925-933.)

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We discuss the presence of anti-keratin antibodies (AKA) of the IgG class in patients with defined juvenile idiopathic arthritis (JIA). An indirect immunofluorescence test and rat oesophagus substrate was used for the detection and quantification of AKA antibodies in patients´ sera. Overall 33/60 patients with JIA had sera positive for AKA (55 %, P = 0,0001) ranging from 1:10 to 1:160 dilutions. Following idiopathic arthritis of childhood classification criteria AKA occurred in 2/7 patients with systemic disease (28,6 %), in 13/30 patients with RF negative polyarthritis (43,3 %, P = 0,008) and in 15/18 RF positive polyarthritis (83,3 %, P = 0,000002). AKA were also found in a small cohort of patients with oligoarthritis (1/3) and psoriatic arthritis (2/2). AKA positivity occurred in 3/26 healthy controls at a 1:20 dilution. The presence of AKA was correlated as well as with the severity of the disease. Our study revealed that AKA was present overall in 18/29 patients (62%) with severe JIA and in 12/26 patients (46,2 %) with non-severe disease, however this did not reach statistical significance (P = 0,18). We also observed that AKA remained positive regardless of disease activity. AKA were detectable in 55,6 % patients with active JIA and in 48,6 % patients in the complete or near remission. Acknowledgement: This research was supported by a European Commission (Acronym: EUROBANK, contract no: QOL-2000-14.1), web site http://www.ncl.ac.uk and by grant of 2nd Medical Faculty, Charles University in Prague, VZ no. 111300003. P2The significance of antibodies to cyclic citrullinated peptide, antikeratin antibodies, antiperinuclear factor, rheumatoid factor isotypes and HLA shared epitope in prediction of erosive disease in early rheumatoid arthritis patients J Vencovsky, L Sedova, S Machacek, J Gatterova, V Pesakova, J Kafkova and O Krystufkova Institute of Rheumatology, Prague, Czech RepublicObjectives: To evaluate a predictive value of autoantibody examinations in development of erosive disease in early rheumatoid arthritis (RA). Patients and methods: One hundred and fourteen patients with disease duration less than 2 years after the onset of symptoms were investigated. Only patients who fulfilled the diagnostic criteria for RA either at the beginning of the disease or during the follow-up period were included. The antibodies to cyclic citrullinated peptide (anti-CCP) (Immunoscan RA, Euro-diagnostica, The Netherlands), IgM, IgA and IgG rheumatoid factors (RF) were measured by ELISA, antikeratin antibodies (AKA) and antiperinuclear factor (APF) were detected by indirect immunofluorescence, and the presence of HLA shared epitope (HLA SE) was detected by PCR with sequence specific primers. Patients were divided into two groups, either with erosive or non-erosive changes present on the hand or/and feet radiographs at the end of 24 months follow-up. Results: Seventy-six (66.7%) patients developed bony erosion, whereas 38 (33.3%) remained without destructive changes. The initial anti-CCP, AKA, APF, IgM RF, IgA RF, IgG RF ...

QJM SummaryWe describe four cases (from three families) of hereditary factor I deficiency, bringing the total number of cases now reported to 23. In one family there are two affected siblings: one has suffered recurrent pyogenic infections; the other is asymptomatic. In the second family, the patient had recurrent pyogenic infections and a self-limiting vasculitic illness; in the third family, the patient suffered recurrent pyogenic and neisserial infections. All four patients had markedly reduced concentrations of C3 in the serum (family 1 propositus: 28%; family 1 asymptomatic sibling: 15%; family 2: 31%; and family 3: 31 % normal human serum) which was in the form of C3b. Low lgG 2 levels may occur in primary C3 deficiency, and a reduction in lgG 2 concentration to 1.14 g/l (normal: 1.30-5.90 g/l) was found in the patient from family 2. Using radioligand binding assays, we demonstrated increased binding of C3b to erythrocytes in a patient with factor I deficiency. This C3b could not be cleaved by autologous serum but could be cleaved by normal serum or purified factor I. We review and compare the published cases of C3, factor H and factor I deficiency.

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