Absorption of vitamin B12 in rheumatoid arthritis

Anti-intrinsic factor antibodies in systemic lupus erythematosus

As the co-existence of pernicious anaemia (PA) and systemic lupus erythematosus (SLE) has been repeatedly reported, we have investigated the presence of anti-intrinsic factor antibodies (IFAb), the immunological hallmark of PA, in patients diagnosed with SLE. Serum cobalamin levels and IFAb were determined in 30 women diagnosed with SLE as well as in 45 controls. Cobalamin levels were low in 7/30 patients. IFAb were detected in 3/30 sera from patients but in none of the control sera. The presence of IFAb was associated with a low cobalamin concentration, anaemia and macrocytosis in only one patient. There was no evident relationship between the presence of IFAb and serological markers of SLE. We conclude that IFAb may appear in SLE patients, although the cobalamin deficiency described in SLE seems to be due to the presence of IFAb in only a minority of cases.

Occurrence of autoantibodies against intrinsic factor, H,K-ATPase, and pepsinogen in atrophic gastritis and rheumatoid arthritis

The occurrence of autoantibodies against intrinsic factor, H,K-ATPase, and pepsinogen was analysed by means of enzyme-linked immunosorbent assay in three groups of sera. Group 1 comprised sera from 14 rheumatoid arthritis patients with normal acid secretion; group 2, sera from 18 rheumatoid arthritis patients with reduced acid secretion; and group 3, sera from 11 patients with pernicious anaemia or achylia. Groups 1 and 2 were rheumatoid factor-positive, and group 3 was negative. Intrinsic factor autoantibodies were low in groups 1 and 2. In group 3, 9 of the 11 sera (82%) scored positive. The highest titres of H,K-ATPase and pepsinogen autoantibodies were found in groups 2 and 3. Only one serum in group 1 scored positive against H,K-ATPase, and two against pepsinogen, whereas corresponding values were 11 (61%) and 7 (39%) in group 2, and 10 (91%) and 6 (55%) in group 3. Autoantibodies against H,K-ATPase from a pool of patient sera recognized both the alpha- and beta-subunits of the enzyme. The present results support the hypothesis of an autoimmune disease overlap between non-organ-specific rheumatoid arthritis and organ-specific pernicious anaemia.

Gastrin, gastric acid secretion, and gastric microflora in patients with rheumatoid arthritis

The relation between the basal and stimulated gastric acid secretion, plasma gastrin, and the gastric microflora was examined in 45 patients with rheumatoid arthritis. Sixteen patients (36%) had basal achlorhydria, and of these, 10 (22%) had achlorhydria or hypochlorhydria after stimulation with pentagastrin. The peak acid output and acidity showed inverse correlation with the disease duration but were not associated with age or with the degree of physical disability. Hypergastrinaemia was found in nine patients (20%), of whom 6 (13%) had significant titres of parietal cell antibody. The acidity of the peak acid output showed negative correlation with plasma gastrin. It was confirmed that the gastric secretory state is a determinant of plasma gastrin levels and in addition influences the growth of micro-organisms in the gastric lumen. The type of microflora in the non-acid stomach was similar to that found in the saliva. A subgroup of eight females was identified who showed low gastric acid secretion rates, positive bacterial cultures, and atlantoaxial subluxation. Gastrin- and insulin-like immunoreactivities were found in joint fluid. The concentrations reflected their plasma levels, suggesting that the peptides are not released at the inflammatory site, but rather that they reach synovial fluid from circulating blood.