Comparison of the human gastric microbiota in hypochlorhydric states arising as a result of Helicobacter pylori-induced atrophic gastritis, autoimmune atrophic gastritis and proton pump inhibitor use.

Several conditions associated with reduced gastric acid secretion confer an altered risk of developing a gastric malignancy. Helicobacter pylori-induced atrophic gastritis predisposes to gastric adenocarcinoma, autoimmune atrophic gastritis is a precursor of type I gastric neuroendocrine tumours, whereas proton pump inhibitor (PPI) use does not affect stomach cancer risk. We hypothesised that each of these conditions was associated with specific alterations in the gastric microbiota and that this influenced subsequent tumour risk. 95 patients (in groups representing normal stomach, PPI treated, H. pylori gastritis, H. pylori-induced atrophic gastritis and autoimmune atrophic gastritis) were selected from a cohort of 1400. RNA extracted from gastric corpus biopsies was analysed using 16S rRNA sequencing (MiSeq). Samples from normal stomachs and patients treated with PPIs demonstrated similarly high microbial diversity. Patients with autoimmune atrophic gastritis also exhibited relatively high microbial diversity, but with samples dominated by Streptococcus. H. pylori colonisation was associated with decreased microbial diversity and reduced complexity of co-occurrence networks. H. pylori-induced atrophic gastritis resulted in lower bacterial abundances and diversity, whereas autoimmune atrophic gastritis resulted in greater bacterial abundance and equally high diversity compared to normal stomachs. Pathway analysis suggested that glucose-6-phospahte1-dehydrogenase and D-lactate dehydrogenase were over represented in H. pylori-induced atrophic gastritis versus autoimmune atrophic gastritis, and that both these groups showed increases in fumarate reductase. Autoimmune and H. pylori-induced atrophic gastritis were associated with different gastric microbial profiles. PPI treated patients showed relatively few alterations in the gastric microbiota compared to healthy subjects.

[A Case of WDHA Water Diarrhea Hypokalemia Achlorhydria Syndrome that Developed after Multimodal Therapy for Retroperitoneal Paraganglioma].

A 45-year-old woman visited a local clinic with left-flank abdominal pain. Abdominal computed tomography (CT) revealed a tumor 20 cm in diameter in the left adrenal gland. She was referred to our hospital for further treatment. No endocrinological abnormality was detected on either serum or urine examination. CT and haematology findings led to a preoperative diagnosis of primary adrenal carcinoma, and we performed a left adrenalectomy. Histopathological examination revealed a paraganglioma with intact adrenal gland. Therefore we diagnosed this case as primary retroperitoneal paraganglioma. Six months after the surgery, she developed peritoneal dissemination including bilateral ovarian metastases. After cytoreductive metastasectomy, she received 131I-meta-iodobenzylguanidine (MIBG) radiotherapy. During the following five-year follow-up, MIBG radiotherapy in conjunction with cytoreductive metastasectomy (3 surgeries and 6 sessions of 131I-MIBG radiotherapy) was performed, aiming at disease control. Five years after the initial surgery, liver, lung, and intra-peritoneal dissemination progressed. Thereafter, she developed severe diarrhea, hypokalemia, and metabolic acidosis with an elevated level of vasoactive intestional peptide, which was consistent with water diarrhea, hypokalemia, achlorhydria (WDHA) syndrome. Despite intensive treatments such as with a somatostatin analogue, she died two months after the onset of this syndrome.

Helicobacter pylori virulence factors affecting gastric proton pump expression and acid secretion.

Acute Helicobacter pylori infection of gastric epithelial cells and human gastric biopsies represses H,K-ATPase α subunit (HKα) gene expression and inhibits acid secretion, causing transient hypochlorhydria and supporting gastric H. pylori colonization. Infection by H. pylori strains deficient in the cag pathogenicity island (cag PAI) genes cagL, cagE, or cagM, which do not transfer CagA into host cells or induce interleukin-8 secretion, does not inhibit HKα expression, nor does a cagA-deficient strain that induces IL-8. To test the hypothesis that virulence factors other than those mediating CagA translocation or IL-8 induction participate in HKα repression by activating NF-κB, AGS cells transfected with HKα promoter-Luc reporter constructs containing an intact or mutated NF-κB binding site were infected with wild-type H. pylori strain 7.13, isogenic mutants lacking cag PAI genes responsible for CagA translocation and/or IL-8 induction (cagA, cagζ, cagε, cagZ, and cagß), or deficient in genes encoding two peptidoglycan hydrolases (slt and cagγ). H. pylori-induced AGS cell HKα promoter activities, translocated CagA, and IL-8 secretion were measured by luminometry, immunoblotting, and ELISA, respectively. Human gastric biopsy acid secretion was measured by microphysiometry. Taken together, the data showed that HKα repression is independent of IL-8 expression, and that CagA translocation together with H. pylori transglycosylases encoded by slt and cagγ participate in NF-κB-dependent HKα repression and acid inhibition. The findings are significant because H. pylori factors other than CagA and IL-8 secretion are now implicated in transient hypochlorhydria which facilitates gastric colonization and potential triggering of epithelial progression to neoplasia.

A rare case of watery diarrhea, hypokalemia and achlorhydria syndrome caused by pheochromocytoma.

BACKGROUND: A rare syndrome of watery diarrhea, hypokalemia and achlorhydria (WDHA) is usually caused by pancreatic endocrine tumors that secrete excessive vasoactive intestinal polypeptide (VIP). Here we report a rare case of WDHA caused by a pheochromocytoma. CASE PRESENTATION: A 45-year old male presented with persistent and progressive watery diarrhea for half a year, and was treated with dialysis due to azotemia, hypokalemia, hypercalcemia and metabolic acidosis. A right adrenal mass was found by ultrasonography, and Positron Emission Tomography-Computed Tomography (PET-CT) showed the tumor was hyper-metabolic. Levels of plasma normetanephrine (NMN) and serum chromogranin A (CgA) were significantly elevated. Immunohistochemistry analysis of the adrenal tumor was strongly positive for CgA, synaptophysin and VIP. The patient fully recovered from WDHA syndrome soon after surgery, as reflected in that diarrhea stopped, levels of plasma NMN, serum CgA, and electrolytes returned to normal thus no dialysis was needed. The patient remained disease free in a 12-months follow-up period. CONCLUSION: We report an extremely rare case of pheochromocytoma causing WDHA syndrome and uremia, which the patient completely recovered from after tumor resection.

Parietal Cell Dysfunction: A Rare Cause of Gastric Neuroendocrine Neoplasm with Achlorhydria and Extreme Hypergastrinemia.

A 69-year-old woman with multiple neuroendocrine neoplasms (NENs) was referred to our hospital. Although she had extreme hypergastrinemia (11,675 pg/mL), no findings that indicated types I to III gastric NENs were found. Although gastric corpus atrophy was suspected on conventional white-light imaging, findings on magnifying endoscopy with narrow-band imaging indicated no severe atrophy. A biopsy from the background fundic gland mucosa revealed no atrophic changes, parietal cells with vacuolated cytoplasm and negative findings for H+K+-ATPase. Thus, this case was diagnosed as multiple NENs with parietal cell dysfunction. Neither progression nor metastasis has been confirmed during two-year follow-up.

Common Pitfalls in the Management of Patients with Micronutrient Deficiency: Keep in Mind the Stomach.

Micronutrient deficiencies are relatively common, in particular iron and cobalamin deficiency, and may potentially lead to life-threatening clinical consequences when not promptly recognized and treated, especially in elderly patients. The stomach plays an important role in the homeostasis of some important hematopoietic micronutrients like iron and cobalamin, and probably in others equally important such as ascorbic acid, calcium, and magnesium. A key role is played by the corpus oxyntic mucosa composed of parietal cells whose main function is gastric acid secretion and intrinsic factor production. Gastric acid secretion is necessary for the digestion and absorption of cobalamin and the absorption of iron, calcium, and probably magnesium, and is also essential for the absorption, secretion, and activation of ascorbic acid. Several pathological conditions such as Helicobacter pylori-related gastritis, corpus atrophic gastritis, as well as antisecretory drugs, and gastric surgery may interfere with the normal functioning of gastric oxyntic mucosa and micronutrients homeostasis. Investigation of the stomach by gastroscopy plus biopsies should always be considered in the management of patients with micronutrient deficiencies. The current review focuses on the physiological and pathophysiological aspects of gastric acid secretion and the role of the stomach in iron, cobalamin, calcium, and magnesium deficiency and ascorbate homeostasis.

[Verner-Morrison syndrome: a case study]. / Verner-Morrison-szindróma egy esete.

Verner and Morrison described a syndrome of watery diarrhea, hypokalemia, and achlorhydria (WDHA) in 1958. VIPomas producing high amounts of vasoactive intestinal peptide (VIP) commonly originate from the pancreas. Typical symptoms play a momentous role in the diagnosis of VIPoma. Diarrhea may persist for years before the diagnosis. Morbidity from untreated WDHA syndrome is associated with long-standing dehydration and with electrolyte and acid-base metabolism disorders, which may cause chronic renal failure. Assessment of specific marker (VIP) offers high sensitivity in establishing the diagnosis. Imaging modalities include endoscopic ultrasonography, computed tomography and magnetic resonance imaging, and particularly, scintigraphy with somatostatin analogues. Treatment options include resection of the tumor, chemotherapy or the reduction of symptoms with somatostatin analogues. Early diagnosis and management may affect survival of patients favorably. VIPoma cases may be associated with multiple endocrine neoplasia type 1.

Increased mortality in prostate carcinoma and smoking-related disease after parietal cell vagotomy: a long-term follow-up study.

OBJECTIVE: There is an increased risk of gastrointestinal carcinoma and smoking-related diseases after partial gastrectomy for peptic ulcer disease. The purpose of this study was to evaluate long-term cancer incidence and mortality after parietal cell vagotomy (PCV), a surgical method with a low rate of side effects, but creating hypochlorhydria in the stomach mimicking long-term treatment with antisecretory drugs. MATERIAL AND METHODS: Data on 383 ulcer patients operated on with PCV during 1971-80 at Lund University Hospital were compared with the national registers for cause of death and cancer incidence for selected diagnoses. Median follow-up was 28 years and 31 years, respectively. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated. RESULTS: An increased incidence of cancer in the respiratory organs (SIR 1.97, 95% CI: 1.08-3.31) and prostate carcinoma (SIR 1.85, 95% CI: 1.22-2.69) was found, and among men also an increased mortality in prostate carcinoma (SMR 3.85, 95% CI: 1.41-8.38) and chronic respiratory disease (SMR 2.76, 95% CI: 1.01-6.02). Overall mortality was similar to that of the background population and no increased risk of gastrointestinal malignancies was observed. CONCLUSIONS: Patients with peptic ulcer operated on with PCV have a long-term increased risk of smoking-related diseases, but PCV does not seem to increase the risk of gastrointestinal carcinoma. An increased risk of, and mortality in prostate carcinoma was found, a cancer previously not found to be related to smoking. This might be the result of surgery-induced hypochlorhydria, which warrants further investigation in patients on long-term proton-pump inhibitors.

Tumor with watery diarrhoea, hypokalaemia in a 3-year-old girl.

Watery diarrhoea, hypokalaemia and achlorhydria (WDHA) syndrome was caused by vasoactive intestinal polypeptide (VIP)-producing tumour. A 3-year-old Chinese girl with watery diarrhoea, abdominal distension and hypokalaemia due to a thoracic paraspinal VIP-secreting ganglioneuroma is reported. The girl coughed, fevering up to 39 degrees C after a flu-like episode. She had eight to ten abundant stools daily which is not improved by dietary treatment, resulting in an important weight loss. She weighed 6.8 kg (nl P50 at 6 months of age) and is 76 cm (nl P50 at 9 months of age) in height. Blood electrolytes showed 129 mmol/L sodium, 2.42 mmol/L potassium, 94 mmol/L chloride and 18.6 mmol/L bicarbonate; urinary catecholamines were normal. Computed tomography scan evidenced a left side paravertebral mass of 4 x 6 cm in the lower thoracic region leading to the blood determination of vasoactive intestinal polypeptide which amounted 830 pmol/L(normal < 25 pmol/L). Surgical removal showed a ganglioneuroma of 160 g and was associated with disappearance of the diarrhoea and normalization of VIP level below 20 pmol/L. Review of the 63 reported cases in children with WDHA showed that many of the cases presented with non-treatable watery diarrhoea, hypokalaemia. Achlorhydria is not necessarily part of the WDHA syndrome. The male to female ratio is 1:1.5. Ganglioneuroblastoma and ganglioneuroma are the commonest tumours. Location of the tumour is variable: abdomen, chest or neck. Abdominal distension, flushing, episodic hypertension and colonic dilatation, constipation and ataxia were the other associated features. Surgical resection is the treatment of choice of VIP-producing tumours.

Hypokalemic rhabdomyolysis due to watery diarrhea, hypokalemia, achlorhydria (WDHA) syndrome caused by vipoma.

Mild hypokalemia is common and encountered in a multitude of diseases, but severe hypokalemia leading to rhabdomyolysis is relatively rare. The watery diarrhea, hypokalemia, achlorhydria (WDHA) syndrome caused by vasoactive intestinal polypeptide (VIP)-producing tumors, is an extremely rare cause of hypokalemic rhabdomyolysis and the literature is limited to one case report. We report a second case of an adult who presented with rhabdomyolysis due to severe hypokalemia. Further evaluation revealed that he had a VIP-producing pancreatic neuroendocrine tumor (NET), which was the cause of his hypokalemic rhabdomyolysis. Although rare in occurrence, a high index of suspicion is of paramount importance for establishing the correct diagnosis and treatment.

Obesity, bariatric surgery, and iron deficiency: true, true, true and related.

Morbid obesity is a health problem that has been shown to be refractory to diet, exercise, and medical treatment. Surgeries designed to promote weight loss, termed bariatric surgery and typically involving a gastric bypass procedure, have recently been implemented to treat obesity with high success rates. However, long-term sequelae can result in micronutrient deficiencies. This review will focus on iron deficiency and its association with obesity and bariatric surgery. Iron deficiency develops after gastric bypass for several reasons including intolerance for red meat, diminished gastric acid secretion, and exclusion of the duodenum from the alimentary tract. Menstruating women, pregnant women, and adolescents may be particularly predisposed toward developing iron deficiency and microcytic anemias after bypass surgery. Preoperative assessment of patients should include a complete hematological work-up, including measurement of iron stores. Postoperatively, oral iron prophylaxis and vitamin C in addition to a multivitamin should be prescribed for bypass patients, especially for vulnerable populations. Once iron deficiency has developed, it may prove refractory to oral treatment, and require parenteral iron, blood transfusions, or surgical interventions. Bariatric surgery patients require lifelong follow-up of hematological and iron parameters since iron deficiency and anemia may develop years after surgery.

Proton pump inhibitors in cirrhosis: tradition or evidence based practice?

Proton pump inhibitors (PPI) are very effective in inhibiting acid secretion and are extensively used in many acid related diseases. They are also often used in patients with cirrhosis sometimes in the absence of a specific acid related disease, with the aim of preventing peptic complications in patients with variceal or hypertensive gastropathic bleeding receiving multidrug treatment. Contradicting reports support their use in cirrhosis and evidence of their efficacy in this condition is poor. Moreover there are convincing papers suggesting that acid secretion is reduced in patients with liver cirrhosis. With regard to Helicobacter pylori (H pylori) infection, its prevalence in patients with cirrhosis is largely variable among different studies, and it seems that H pylori eradication does not prevent gastro-duodenal ulcer formation and bleeding. With regard to the prevention and treatment of oesophageal complications after banding or sclerotherapy of oesophageal varices, there is little evidence for a protective role of PPI. Moreover, due to liver metabolism of PPI, the dose of most available PPIs should be reduced in cirrhotics. In conclusion, the use of this class of drugs seems more habit related than evidence-based eventually leading to an increase in health costs.

Clinical manifestations of chronic atrophic gastritis.

Although the actual prevalence of chronic atrophic gastritis is unknown and it is probable that this entity goes largely underdiagnosed, patients in whom diagnosis is established usually present advanced stages of disease. Destruction of parietal cells, either autoimmune-driven or as a consequence of Helicobacter pylori infection, determines reduction or abolition of acid secretion. Hypo/achloridia causes an increase in serum gastrin levels, with an increased risk of the development of neuroendocrine tumors. Microcytic, hypochromic anemia frequently precedes the development of megaloblastic, vitamin B12-associated anemia. Moreover, vitamin B12 deficiency,may cause elevation of homocysteine, with an increase in the cardiovascular risk, and may be associated with neurological manifestations, mainly characterized by spinal cord demyelination and atrophy, with ensuing sensory-motor abnormalities. Gastrointestinal manifestations seem to be associated with non-acid reflux and tend to be non-specific.

HIV related hypochlorhydria does not appear to respond to anti-retroviral therapy in Zambian adults: a case control study.

INTRODUCTION: Human Immunodeficiency Virus (HIV) infection is associated with hypochlorhydria but the mechanism is unknown. The objective of this study was to determine effects of anti-retroviral therapy (ART) on gastric physiology as measured by validated markers. METHODS: We studied HIV infected individuals who were either ART-naïve or on treatment with undetectable viral loads. We measured H.pylori IgG antibodies, pepsinogen (PG) 1 and 2 levels and fasting gastrin-17 using Biohit GastroPanel®. Gastric antral biopsies and juice were obtained for histology and pH respectively. Also included were historical data from HIV negative participants (n = 72) in a previous study, for reference. RESULTS: We enrolled 84 HIV positive individuals with a median age 42 years (IQR 37-40 years). 55(66%) were female, 32(38%) were ART naïve, and 52(62%) were on ART. Hypochlorhydria (pH>4) was present in 48(57%) of the HIV positive and 18(25%) of the HIV negative individuals (OR 4: 95% CI 1.9-8.5, P<0.001) with no significant effect of ART (OR 0.9: 95% CI 0.3-2.3, P = 0.82). Hypochlorhydria was not associated with the serological detection of corpus atrophy using low PG 1:2 ratio (OR 2.1: 95% CI 0.5-10.2, P = 0.37) or GastroPanel® algorithm, (OR 0.7: 95% CI 0.01-60.1, P = 1.0). ART reduced the frequency of low PG 1:2 ratio (P = 0.001), but not the histological detection in the antrum of atrophy or non-atrophic gastritis. CONCLUSION: ART use is associated with reduced serological evidence of corpus atrophy but has no effect on fasting pH, supporting earlier data that suggest that the mechanism of HIV-associated hypochlorhydria is multifactorial.

Watery diarrhea, hypokalemia and achlorhydria syndrome due to an adrenal pheochromocytoma.

Watery diarrhea, hypokalemia and achlorhydria (WDHA) syndrome caused by vasoactive intestinal polypeptide (VIP) -producing tumor only rarely occurs in patients with nonpancreatic disease. A 49-year-old woman was referred for evaluation of a right adrenal tumor incidentally diagnosed by abdominal ultrasound during the investigation of chronic watery diarrhea. Laboratory findings showed hypokalemia and excessive production of VIP and catecholamines. After surgical resection of the tumor, diarrhea subsided and both electrolytes and affected hormone levels normalized. Immunohistochemical examination confirmed a diagnosis of pheochromocytoma, which contained VIP-positive ganglion-like cells. We herein present the clinical and histogenetic implications of this rare clinical entity, with literature review.

Vipoma of the pancreas: observations on the diarhrhea and circulatory disturbances.

A patient with a vipoma of the pancreas and persistently elevated blood levels of vasoactive intestinal polypeptide (VIP) had watery diarrhea, hypokalemia, and achlorhydria (WDHA syndrome). In the untreated state, the diarrhea was never profuse. Fecal volumes ranged from 0.16 to 1.24 L/day. Attempts to correct the dehydration by fluid and electrolyte loading resulted in a massive increase in fecal water and electrolyte loss. Prednisone cured the diarrhea and was associated with a decrease in plasma VIP levels. The patient had a marked circulatory disturbance with systemic arterial hypotension and cutaneous vasodilation that caused a subnormal body temperature. Removal of the tumor led to a dramatic change in the patient's circulation. Generalized vasodilation with systemic venous and arterial hypotension gave away to vasoconstriction with severe venous and arterial hypertension. Central venous pressure rose from -4.4 to +4.0 cm H2O and arterial pressure rose from 80/55 to 195/110 mm Hg. These changes might explain the unexpected and sometimes fatal heart failure that has complicated the removal of these tumors from some patients.

Is achlorhydria a cause of iron deficiency anemia?

We re-evaluated the old hypothesis that gastritis-induced achlorhydria is a cause of iron deficiency anemia (IDA) in humans. First, we analyzed the currently available research on the association between achlorhydria and IDA. When gastric acid secretion was measured after maximal stimulation, the frequency of achlorhydria (or severe hypochlorhydria) was 44% in patients with idiopathic IDA and 1.8% in healthy controls. In some patients with pernicious anemia, presumed achlorhydria preceded the development of IDA in time. However, we found no credible evidence that IDA caused gastritis or that IDA preceded the development of achlorhydria. Thus, correlational results favor achlorhydria as the causal factor in the association between achlorhydria and IDA. Second, we sought to determine whether gastritis and achlorhydria cause negative iron balance. When biosynthetic methods were used to isotopically label iron in food, achlorhydric patients were found to have severe malabsorption of nonheme iron, which persisted after the development of IDA. In 1 study, achlorhydria reduced the normal increase in heme-iron absorption from hemoglobin in response to iron deficiency. After an injection of isotopic iron into normal men, the physiologic loss of iron from the body was found to be 1 mg/d. Patients with chronic gastritis had excess fecal loss of isotopically tagged plasma iron. Calculations based on these results indicate that the absorption of iron from a typical Western diet by achlorhydric patients would be less than physiologic iron losses, creating a negative iron balance that could not be overcome by the adaptive increase in duodenal iron absorptive capacity that occurs in response to iron deficiency. The combination of results from these correlational and pathophysiologic studies supports the hypothesis that gastritis-induced achlorhydria can be an independent cause of IDA.

Helicobacter pylori, HIV and Gastric Hypochlorhydria in the Malawian Population.

BACKGROUND: HIV and Helicobacter pylori are common chronic infections in sub-Saharan Africa. Both conditions can predispose to gastric hypochlorhydria that may be a risk factor for enteric infections and reduced drug absorption. We have investigated to what extent HIV and H. pylori infections are associated with hypochlorhydria in a Malawian cohort of patients undergoing endoscopy. METHODS: 104 sequential symptomatic adults referred for gastroscopy at Queen Elizabeth Central Hospital, Blantyre, Malawi, had blood taken for rapid HIV testing and fasting serum gastrin analysis. Gastric fluid was aspirated for pH testing, and gastric biopsies were taken. RESULTS: After 9/104 HIV-infected patients who were already established on anti-retroviral therapy were excluded, 17/95 (25.0%) were seropositive for untreated HIV, and 68/95 (71.6%) patients were H. pylori positive by histology. Hypochlorhydria (fasting gastric pH>4.0) was present in 55.8% (53/95) of patients. H. pylori infection was significantly associated with hypochlorhydria (OR 2.91, [1.02-7.75], p=0.046). While single infection with HIV was not significantly independently associated with hypochlorhydria. H. pylori and HIV co-infection was more strongly associated with hypochlorhydria (OR 6.25, [1.33-29.43], p=0.020) than either infection alone, suggesting an additive effect of co-infection. HIV infection was associated with higher serum gastrin levels (91.3 pM vs. 53.1 pM, p=0.040), while H. pylori infection was not (63.1 pM vs. 55.1 pM, p=0.610). Irrespective of H. pylori and HIV status, most patients (>90%) exhibited pangastritis. Only three patients had histological evidence of gastric atrophy, of which only one was HIV-infected. CONCLUSION: H. pylori infection was associated with fasting hypochlorhydria, while HIV was not independently associated. HIV and H. pylori co-infection, however, was more strongly associated with hypochlorhydria than H. pylori infection alone. The mechanism of this apparent additive effect between HIV and H. pylori remains unclear, but appears to be related to chronic pangastritis rather than gastric atrophy, and associated with hypergastrinaemia in HIV-infected individuals.

Interrelationships between the B-vitamins in B12-deficiency neuromyelopathy. A possible malabsorption-malnutrition syndrome.

Five patients presenting clinically with a form B12-deficiency neuromyelopathy, with cord involvement in all and proximal muscle weakness in two of them, were investigated for their neurologic, hematologic and vitamin status. Megaloblastosis and achlorhydria were present in all, and impaired absorption of 57Co vitamin B12 and of D-xylose was detected in four. Total cyanide extracted vitamin B12 (A) was lowered in all cases and noncyanide extractable (B) in four of the five, being zero in three. All five responded to injections of hydroxocobalamin. In two patients sequential estimations showed that both A and B, especially the latter, rose steeply initially, normalizing at 50% of A after some weeks. Moiety B is suggested to be physiologically the more active and dissociable form of vitamin B12. Markedly elevated initial serum folate levels, and their subsequent fall under treatment with B12, indicated the operation of the "methyltetrahydrofolate trap". Blood levels of thiamin, nicotinic acid and pantothenic acid were within normal limits. However, serum riboflavin (B2) total vitamin B6 and pyridoxal were reduced in all where tested. Vitamin B6 deficiency could have resulted from its own malabsorption and have contributed to be B12 deficiency. Vitamin B2 and B6 levels also corrected themselves on B12 therapy. The B-vitamin deficiencies in our patients probably resulted from intestinal malabsorption, with a possible factor of malnutrition consequent to their strictly vegetarian diet.