Non-criteria Antiphospholipid Antibodies: a narrative review.

The 2006 Revised Sapporo Classification Criteria for Definite Antiphospholipid Syndrome included as laboratory criteria the tests for antiphospholipid antibodies whose accuracy was regarded as satisfactory according to the evidence available at that time. In practice, however, the sensitivity and specificity of these "criteria" of antiphospholipid antibodies are sometimes insufficient for identifying or ruling out antiphospholipid syndrome. It has been studied whether the accuracy of the laboratory diagnosis of the syndrome could be improved by testing for non-criteria antiphospholipid antibodies. In this work, we review evidence on the clinical associations and diagnostic value of the most commonly studied non-criteria antibodies, namely: antiphosphatidylethanolamine, anti-annexin A5, anti-prothrombin, anti-phosphatidylserine/prothrombin complex, IgA anticardiolipin, and IgG anti-domain I of the ß2 glycoprotein antibodies.

Non-criteria Antiphospholipid Antibodies: a narrative review

SUMMARY The 2006 Revised Sapporo Classification Criteria for Definite Antiphospholipid Syndrome included as laboratory criteria the tests for antiphospholipid antibodies whose accuracy was regarded as satisfactory according to the evidence available at that time. In practice, however, the sensitivity and specificity of these "criteria" of antiphospholipid antibodies are sometimes insufficient for identifying or ruling out antiphospholipid syndrome. It has been studied whether the accuracy of the laboratory diagnosis of the syndrome could be improved by testing for non-criteria antiphospholipid antibodies. In this work, we review evidence on the clinical associations and diagnostic value of the most commonly studied non-criteria antibodies, namely: antiphosphatidylethanolamine, anti-annexin A5, anti-prothrombin, anti-phosphatidylserine/prothrombin complex, IgA anticardiolipin, and IgG anti-domain I of the β2 glycoprotein antibodies.

RESUMO A classificação de Sapporo revisada para a síndrome antifosfolipídica definida de 2006 incluiu como critérios laboratoriais aqueles testes para anticorpos antifosfolípides cuja acurácia era considerada satisfatória de acordo com a evidência então disponível. Porém, na prática, a sensibilidade e especificidade desses anticorpos antifosfolípides "critério" são por vezes insuficientes para identificar ou descartar a síndrome antifosfolípide. Tem-se estudado se a acurácia do diagnóstico laboratorial da síndrome poderia ser melhorada por meio da testagem de anticorpos antifosfolípides não critério. Neste trabalho revisamos a evidência a respeito das associações clínicas e valor diagnóstico dos anticorpos não critério mais estudados, nomeadamente: anticorpos antifosfatidiletanolamina, antianexina A5, antiprotrombina, anticomplexo fosfatidilserina/protrombina, IgA anticardiolipina e IgG antidomínio I da anti-β2 glicoproteína I.

Antiphospholipid Syndrome Committee of the Brazilian Society of Rheumatology position statement on the use of direct oral anticoagulants (DOACs) in antiphospholipid syndrome (APS).

BACKGROUND: The term Direct Oral Anticoagulants (DOACs) refers to a group of drugs that inhibit factor Xa or thrombin. Even though their use for treating different thrombotic or prothrombotic conditions is increasing recently, there is no compelling evidence indicating that those medications are safe in all antiphospholipid syndrome (APS) patients. METHODOLOGY: To address this issue, specialists from the Antiphospholipid Syndrome Committee of the Brazilian Society of Rheumatology performed a comprehensive review of the literature regarding DOACs use in APS to answer the three following questions: (1) potential mechanisms of action of these drugs that could be relevant to APS pathogenesis, (2) DOACs interference on lupus anticoagulant testing, and (3) the efficacy of DOACs in APS. POSITION STATEMENT: After critically reviewing the relevant evidence, the authors formulated 8 Position Statements about DOACs use in APS. CONCLUSION: DOACs should not be routinely used in APS patients, especially in those with a high-risk profile (triple positivity to aPL, arterial thrombosis, and recurrent thrombotic events). In addition, DOACs interferes with LA testing, leading to false-positive results in patients investigating APS.

Real world experience of patients with amyotrophic lateral sclerosis (ALS) in the treatment of spasticity using tetrahydrocannabinol:cannabidiol (THC:CBD).

BACKGROUND: Treatment of spasticity poses a major challenge in amyotrophic lateral sclerosis (ALS) patient management. Delta-9-tetrahydrocannabinol (THC):cannabidiol (CBD) oromucosal spray (THC:CBD), approved for the treatment of spasticity in multiple sclerosis, serves as a complementary off-label treatment option in ALS-related spasticity. However, few structured data are available on THC:CBD in the treatment of spasticity in ALS. METHOD: A retrospective mono-centric cohort study was realised in 32 patients that meet the following criteria: 1) diagnosis of ALS, 2) ALS-related spasticity; 3) treatment with THC:CBD. Spasticity was rated using the Numeric Rating Scale (NRS). Patient's experience with THC:CBD was assessed using the net promoter score (NPS) and treatment satisfaction questionnaire for medication (TSMQ-9) as captured through telephone survey or online assessment. RESULTS: The mean dose THC:CBD were 5.5 daily actuations (range < 1 to 20). Three subgroups of patients were identified: 1) high-dose daily use (≥ 7 daily actuations, 34%, n = 11), 2) low-dose daily use (< 7 daily actuations, 50%, n = 16), 3) infrequent use (< 1 daily actuation, 16%, n = 5). Overall NPS was + 4.9 (values above 0 express a positive recommendation to fellow patients). Remarkably, patients with moderate to severe spasticity (NRS ≥ 4) reported a high recommendation rate (NPS: + 29) in contrast to patients with mild spasticity (NRS < 4; NPS: - 44). For the three main domains of TSQM-9 high mean satisfaction levels were found (maximum value 100): effectiveness 70.5 (±22.3), convenience 76.6 (±23.3) and global satisfaction 75.0 (±24.7). CONCLUSION: THC:CBD is used in a wide dose range suggesting that the drug was applied on the basis of individual patients' needs and preferences. Contributing to this notion, moderate to severe spasticity was associated with an elevated number of daily THC:CBD actuations and stronger recommendation rate (NPS) as compared to patients with mild spasticity. Overall, treatment satisfaction (TSQM-9) was high. The results suggest that THC:CBD may serve as a valuable addition in the spectrum of symptomatic therapy in ALS. However, prospective studies and head-to-head comparisons to other spasticity medications are of interest to further explore the effectiveness of THC:CBD in the management of spasticity, and other ALS-related symptoms.

Patient-Reported Outcome of Physical Therapy in Amyotrophic Lateral Sclerosis: Observational Online Study.

BACKGROUND: Physical therapy is an essential component of multidisciplinary treatment in amyotrophic lateral sclerosis (ALS). However, the meaning of physical therapy beside preservation of muscular strength and functional maintenance is not fully understood. OBJECTIVE: The purpose of this study was to examine patients' perception of physical therapy during symptom progression using an internet assessment approach. METHODS: A prospective, longitudinal, observational study was performed. Recruitment took place in an ALS center in Berlin, Germany. Online self-assessment was established on a case management platform over 6 months. Participants self-assessed the progression of the disease with the ALS Functional Rating Scale-Revised (ALSFRS-R) and tracked the efficacy of targeted physical therapy using Measure Yourself Medical Outcome Profile (MYMOP). We used the net promoter score (NPS) to inquire into recommendation levels of physical therapy. RESULTS: Forty-five participants with ALS were included in the study. Twenty-seven (60.0%) started the online assessment. The mean duration of physical therapy sessions per week was 142.7 minutes (SD 60.4) with a mean frequency of 2.9 (SD 1.2) per week. As defined by MYMOP input, the most concerning symptoms were reported in the legs (62.2%), arms (31.1%), and less frequently in the torso (6.7%). As expected for a progressive disease, there was a functional decline of 3 points in the ALSFRS-R at the end of the observation period (n=20). Furthermore, the MYMOP showed a significant loss of 0.8 in the composite score, 0.9 in the activity score and 0.8 in the targeted symptom. In spite of functional decline, the recommendation for physical therapy jumped from a baseline value of 20 NPS points to a very high 50 points at the end of study (P=.05). CONCLUSIONS: Physical therapy is perceived as an important treatment method by patients with ALS. Despite functional deterioration, patients are satisfied with physical therapy and recommend this intervention. The results also underline how the meaning of physical therapy changes throughout the disease. Physical therapy in ALS has to be regarded as a supportive and palliative health care intervention beyond functional outcome parameters.

Implementing Motor Unit Number Index (MUNIX) in a large clinical trial: Real world experience from 27 centres.

OBJECTIVE: Motor Unit Number Index (MUNIX) is a quantitative neurophysiological method that reflects loss of motor neurons in Amyotrophic Lateral Sclerosis (ALS) in longitudinal studies. It has been utilized in one natural history ALS study and one drug trial (Biogen USA) after training and qualification of raters. METHODS: Prior to testing patients, evaluators had to submit test-retest data of 4 healthy volunteers. Twenty-seven centres with 36 raters measured MUNIX in 4 sets of 6 different muscles twice. Coefficient of variation of all measurements had to be <20% to pass the qualification process. MUNIX COV of the first attempt, number of repeated measurements and muscle specific COV were evaluated. RESULTS: COV varied considerably between raters. Mean COV of all raters at the first measurements was 12.9% ±â€¯13.5 (median 8.7%). Need of repetitions ranged from 0 to 43 (mean 10.7 ±â€¯9.1, median 8). Biceps and first dorsal interosseus muscles showed highest repetition rates. MUNIX variability correlated considerably with variability of compound muscle action potential. CONCLUSION: MUNIX revealed generally good reliability, but was rater dependent and ongoing support for raters was needed. SIGNIFICANCE: MUNIX can be implemented in large clinical trials as an outcome measure after training and a qualification process.

Provision of assistive technology devices among people with ALS in Germany: a platform-case management approach.

OBJECTIVE: The procurement of assistive technology devices (ATD) is an essential component of managed care in ALS. The objective was to analyze the standards of care for ATD and to identify challenges in the provision process. METHODS: A cohort study design was used. We investigated the provision of 11,364 ATD in 1494 patients with ALS at 12 ALS centers in Germany over four years. Participants were patients that entered a case management program for ATD including systematic assessment of ATD on a digital management platform. RESULTS: Wheelchairs (requested in 65% of patients), orthoses (52%), bathroom adaptations (49%), and communication devices (46%) were the most needed ATD. There was a wide range in the number of indicated ATD per patient: 1 to 4 ATD per patient in 45% of patients, 5 to 20 ATD in 48%, and >20 ATD in 7% of patients. Seventy percent of all requested ATD were effectively delivered. However, an alarming failure rate during procurement was found in ATD that are crucial for ALS patients such as powered wheelchairs (52%), communication devices (39%), or orthoses (21%). Leading causes for not providing ATD were the refusal by health insurances, the decision by patients, and the death of the patient before delivery of the device. CONCLUSIONS: The need for ATD was highly prevalent among ALS patients. Failed or protracted provision posed substantial barriers to ATD procurement. Targeted national strategies and the incorporation of ATD indication criteria in international ALS treatment guidelines are urgently needed to overcome these barriers.

Update on antiphospholipid antibody syndrome / Atualização da síndrome do anticorpo antifosfolípide

Summary Antiphospholipid syndrome (APS) is an autoimmune disease characterized by antiphospholipid antibodies (aPL) associated with thrombosis and/or pregnancy morbidity. Most APS events are directly related to thrombotic events, which may affect small, medium or large vessels. Other clinical features like thrombocytopenia, nephropathy, cardiac valve disease, cognitive dysfunction and skin ulcers (called non-criteria manifestations) add significant morbidity to this syndrome and represent clinical situations that are challenging. APS was initially described in patients with systemic lupus erythematosus (SLE) but it can occur in patients without any other autoimmune disease. Despite the autoimmune nature of this syndrome, APS treatment is still based on anticoagulation and antiplatelet therapy.

Resumo A síndrome antifosfolipídide (APS) é uma doença autoimune caracterizada por tromboses e morbidade gestacional associadas à positividade de antiphospholipid antibodies (aPL). A maioria das manifestações da APS está diretamente relacionada aos eventos trombóticos, que podem afetar pequenos, médios ou grandes vasos. Outras manifestações como trombocitopenia, nefropatia, valvulopatia, disfunção cognitiva e úlceras cutâneas (chamadas de manifestações não critérios) agregam significativa morbidade e muitas vezes são refratárias ao tratamento convencional. Embora tenha sido inicialmente descrita em pacientes com lúpus eritematoso sistêmico (LES), a síndrome antifosfolípide também pode ocorrer em pacientes sem outras doenças autoimunes associadas. Apesar do caráter autoimune dessa síndrome, o tratamento da APS ainda é baseado na anticoagulação e na antiagregação plaquetária.

A importância de reconhecer a síndrome antifosfolípide na medicina vascular / The importance of recognizing antiphospholipid syndrome in vascular medicine

A síndrome antifosfolipíde (SAF) é uma doença autoimune sistêmica caracterizada por trombose arterial ou venosa recorrente e/ou morbidade gestacional e pela presença dos anticorpos antifosfolipídeos, podendo apresentar outras manifestações vasculares, como microangiopatia, arteriopatia crônica e SAF catastrófica. Determinados testes laboratoriais para a síndrome (por exemplo, o anticoagulante lúpico) podem sofrer interferência do uso de medicações anticoagulantes, dificultando o diagnóstico. A fisiopatologia da SAF é complexa, sendo enumerados no texto diversos mecanismos patogênicos relacionados à coagulação, ao endotélio e às plaquetas. Por fim, discutimos o tratamento da SAF de acordo com a presença e o tipo de manifestações clínicas, o uso dos anticoagulantes orais diretos e o manejo perioperatório de pacientes com SAF

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by recurrent arterial or venous thrombosis and/or gestational morbidity and by the presence of antiphospholipid antibodies. It can also cause other vascular manifestations such as microangiopathy, chronic arteriopathy and catastrophic APS (CAPS). Certain laboratory tests for the syndrome (for example, the lupus anticoagulant test) can be affected by the use of anticoagulant agents, making diagnosis more difficult. The pathophysiology of APS is complex, and several mechanisms of pathogenesis related to coagulation, endothelium, and platelets are discussed in this article. We conclude by discussing treatment of APS according to the presence and type of clinical manifestations, use of direct oral anticoagulants (DOAs), and perioperative management of patients with APS

[Comparison of Different Mechanical Insufflator-Exsufflator Systems by Measurement of the Peak Exspiratory Flow (PEF)]. / Vergleich verschiedener mechanischer Hustenhilfen durch Messung der exspiratorischen Spitzenflüsse.

Background The management of pulmonary secretion in patients with respiratory muscle weakness using mechanical insufflator-exsufflator systems (MIE) is an established treatment option. There are significant differences in the efficiency of different devices in practical use. The intention of this study was to evaluate the peak exspiratory flow (PEF) values of different devices with and without use of equipment. Methods PEFs of ten MIE were investigated in vitro using different equipment. Results The efficiency of the devices showed significant differences. The use of two bacterial filters showed a significant reduction of 13 % compared to one filter, the use of a catheter mount revealed a significant reduction of 10 %, with an elbow connector additionally 15 %. With a commonly used equipment (1800 mm tube, one filter, catheter tube with elbow) there was a difference of 58 % between the devices Nippy (2,86 l/s) and Pulsar (1,2 l/s). Conclusion There are significant differences in PEF of different MIE and use of different equipment. That could be of therapeutic relevance. Further studies are needed to investigate the clinical relevance of these findings. Recommendations for the use of devices and equipment are necessary to ensure the efficacy of the elimination of pulmonary mucus.

Clinical characteristics and course of dying in patients with amyotrophic lateral sclerosis withdrawing from long-term ventilation.

Non-invasive ventilation (NIV) or tracheotomy with invasive ventilation (TIV) are treatment options in ALS. However, a proportion of patients receiving long-term ventilation decide to have it withdrawn. The objective of this study was to analyse the clinical characteristics and palliative approaches in ALS patients withdrawing from long-term ventilation (WLTV). In a cohort study, two different palliative concepts in WLTV were studied: (1) augmented symptom control (ASC; sedation not intended) in patients with ventilator-free tolerance; (2) continuous deep sedation (CDS; sedation intended) in patients without ventilator-free tolerance. Results showed that WLTV was realised in 49 ALS patients (NIV = 13; TIV = 36). Mean daily ventilation was 23.4 h. The ALS Functional Rating Scale (ALSFRS-R) was low (5.6 of 48). Forty-one per cent of patients (n = 20) presented with ophthalmoplegia. ASC was performed in 20 patients, CDS in 29 patients. The mean time to death following disconnection was 32 (0.3-164) h during ASC and 0.3 (0.2-0.6) h in CDS. In conclusion, a low ALSFRS-R, high incidence of ophthalmoplegia and extended ventilator dependency were found before WLTV. The presence or absence of ventilator-free tolerance determined the approach to the management of symptoms, the setting for immediate end-of-life care and the course of dying in WLTV.

Update on antiphospholipid antibody syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by antiphospholipid antibodies (aPL) associated with thrombosis and/or pregnancy morbidity. Most APS events are directly related to thrombotic events, which may affect small, medium or large vessels. Other clinical features like thrombocytopenia, nephropathy, cardiac valve disease, cognitive dysfunction and skin ulcers (called non-criteria manifestations) add significant morbidity to this syndrome and represent clinical situations that are challenging. APS was initially described in patients with systemic lupus erythematosus (SLE) but it can occur in patients without any other autoimmune disease. Despite the autoimmune nature of this syndrome, APS treatment is still based on anticoagulation and antiplatelet therapy.

Update on Biologic Therapies for Systemic Lupus Erythematosus.

Systemic lupus erythematosus (SLE) is a chronic multisystemic autoimmune disease driven by genetic, hormonal, and environmental factors. Despite the advances in diagnostic and therapeutic approaches in the last decades, SLE still leads to significant morbidity and increased mortality. Although a cure for SLE is still unknown, treatment is required to control acute disease exacerbation episodes (flares), decrease the frequency and severity of subsequent lupus flares, address comorbidities, and prevent end-organ damage. While conventional SLE pharmacotherapy may exhibit suboptimal efficacy and substantial toxicity, a growing knowledge of the disease pathogenesis enabled the research on novel therapeutic agents directed at specific disease-related targets. In this paper, we review the recent progress in the clinical investigation of biologic agents targeting B cells, T cells, cytokines, innate immunity, and other immunologic or inflammatory pathways. Although many investigational agents exhibited insufficient efficacy or inadequate safety in clinical trials, one of them, belimumab, fulfilled the efficacy and safety regulatory requirements and was approved for the treatment of SLE in Europe and the USA, which confirms that, despite all difficulties, advances in this field are possible.

Dry entrapment of enzymes by epoxy or polyester resins hardened on different solid supports.

Embedding of enzymes was performed with epoxy or polyester resin by mixing in a dried enzyme preparation before polymerization was started. This fast and low-cost immobilization method produced enzymatically active layers on different solid supports. As model enzymes the well-characterized Thermomyces lanuginosus lipase and a new threonine aldolase from Ashbya gossypii were used. It was shown that T. lanuginosus lipase recombinantly expressed in Aspergillus oryzae is a monomeric enzyme with a molecular mass of 34kDa, while A. gossypii threonine aldolase expressed in Escherichia coli is a pyridoxal-5'-phosphate binding homotetramer with a mass of 180kDa. The enzymes were used freeze dried, in four different preparations: freely diffusing, adsorbed on octyl sepharose, as well as cross-linked enzyme aggregates or as suspensions in organic solvent. They were mixed with standard two-component resins and prepared as layers on solid supports made of different materials e.g. metal, glass, polyester. Polymerization led to encapsulated enzyme preparations showing activities comparable to literature values.

Guidelines for the treatment of antiphospholipid syndrome.

The antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by arterial and venous thrombosis, gestational morbidity and presence of elevated and persistently positive serum titers of antiphospholipid antibodies. The treatment of APS is still controversial, because any therapeutic decision potentially faces the risk of an insufficient or excessive antithrombotic coverage associated with anticoagulation and its major adverse effects. This guideline was elaborated from nine relevant clinical questions related to the treatment of APS by the Committee of Vasculopathies of the Brazilian Society of Rheumatology. Thus, this study aimed at establishing a guideline that included the most relevant and controversial questions in APS treatment, based on the best scientific evidence available. The questions were structured by use of the PICO (patient, intervention or indicator, comparison and outcome) process, enabling the generation of search strategies for evidence in the major primary scientific databases (MEDLINE/PubMed, Embase, Lilacs, Scielo, Cochrane Library, Premedline via OVID). A manual search for evidence and theses was also conducted (BDTD and IBICT). The evidence retrieved was selected based on critical assessment by using discriminatory instruments (scores) according to the category of the therapeutic question (JADAD scale for randomized clinical trials and Newcastle-Ottawa scale for non-randomized studies). After defining the potential studies to support the recommendations, they were selected according to level of evidence and grade of recommendation, according to the Oxford classification.

Diretrizes para o tratamento da síndrome do anticorpo antifosfolipídeo / Guidelines for the treatment of antiphospholipid syndrome

A síndrome do anticorpo antifosfolipídeo (SAF) é uma doença sistêmica autoimune caracterizada por trombose arterial e venosa, morbidade gestacional e presença de níveis séricos de anticorpos antifosfolipídeos elevados e persistentemente positivos. O tratamento da SAF ainda é sujeito a controvérsias, já que qualquer decisão terapêutica potencialmente irá confrontar-se com o risco de uma cobertura antitrombótica insuficiente ou com o risco excessivo associado à anticoagulação e seus principais efeitos adversos. Esta diretriz foi elaborada a partir de nove questões clínicas relevantes e relacionadas ao tratamento da SAF pela Comissão de Vasculopatias da Sociedade Brasileira de Reumatologia. O objetivo deste trabalho foi criar uma diretriz que incluísse as questões mais relevantes e controversas no tratamento da SAF, com base na melhor evidência científica disponível. As questões foram estruturadas por meio do P.I.C.O. (paciente, intervenção ou indicador, comparação e outcome/desfecho), o que possibilitou a geração de estratégias de busca da evidência nas principais bases primárias de informação científica (MEDLINE/Pubmed, Embase, Lilacs/Scielo, Cochrane Library, Premedline via OVID). Também realizou-se busca manual da evidência e de teses (BDTD e IBICT). A evidência recuperada foi selecionada a partir da avaliação crítica, utilizando instrumentos (escores) discriminatórios de acordo com a categoria da questão terapêutica (JADAD para ensaios clínicos randomizados e New Castle Ottawa Scale para estudos não randomizados). Após definir os estudos potenciais para sustento das recomendações, eles foram selecionados pela força da evidência e pelo grau de recomendação, segundo a classificação de Oxford.

The antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by arterial and venous thrombosis, gestational morbidity and presence of elevated and persistently positive serum titers of antiphospholipid antibodies. The treatment of APS is still controversial, because any therapeutic decision potentially faces the risk of an insufficient or excessive antithrombotic coverage associated with anticoagulation and its major adverse effects. This guideline was elaborated from nine relevant clinical questions related to the treatment of APS by the Committee of Vasculopathies of the Brazilian Society of Rheumatology. Thus, this study aimed at establishing a guideline that included the most relevant and controversial questions in APS treatment, based on the best scientific evidence available. The questions were structured by use of the PICO (patient, intervention or indicator, comparison and outcome) process, enabling the generation of search strategies for evidence in the major primary scientific databases (MEDLINE/PubMed, Embase, Lilacs, Scielo, Cochrane Library, Premedline via OVID). A manual search for evidence and theses was also conducted (BDTD and IBICT). The evidence retrieved was selected based on critical assessment by using discriminatory instruments (scores) according to the category of the therapeutic question (JADAD scale for randomized clinical trials and Newcastle-Ottawa scale for non-randomized studies). After defining the potential studies to support the recommendations, they were selected according to level of evidence and grade of recommendation, according to the Oxford classification.

Growth stress triggers riboflavin overproduction in Ashbya gossypii.

The filamentous fungus Ashbya gossypii is used for riboflavin biosynthesis on an industrial scale, but even the wild type displays overproduction. Because riboflavin overproduction was known to start at the transition between growth and stationary phase, it was suspected that overproduction was induced at low growth rates. However, chemostatic cultivations performed at different growth rates did not result in any detectable riboflavin formation. In this study, we report that it was not the final growth rate that triggered riboflavin overproduction but a decline in growth rate. Therefore, continuous fermenter cultivations with dilution rate shifts were performed. Peaks of riboflavin overproduction were observed in the wild type and in a RIB3placZ reporter strain after downshifts in dilution rate. Accumulation of riboflavin correlated with an increased expression of lacZ reporter activity. The step size of the downshifts corresponded to the peak size of riboflavin formation and reporter activity. Expression of further RIB genes encoding riboflavin biosynthetic enzymes was analyzed by RT-PCR. RIB mRNA levels of the ribulose-5-phosphate branch of the divided riboflavin biosynthesis pathway (RIB3, RIB4, and RIB5) were found to increase in the riboflavin production phase, whereas the RIB2 and RIB7 mRNA levels belonging to the GTP branch remained constant. We propose that a decline in growth rate triggers the increased expression of RIB3, RIB4, and RIB5 resulting in riboflavin overproduction. Because although a reduction in oxygen supply, temperature increase or decrease, or salt stress did affect growth, but neither did lead to riboflavin overproduction nor did induce RIB3 reporter expression, we conclude that declining nutrition must be the stress stimulus. Because about half of the cells in the hyphae of Ashbya gossypii did not accumulate riboflavin, the regulatory response on the cellular level can be estimated to be at least twice as great in comparison to what we detected as overall signals.